pg_hint_plan.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pg_hint_plan.c
   4  *                hinting on how to execute a query for PostgreSQL
   5  *
   6  * Copyright (c) 2012-2020, NIPPON TELEGRAPH AND TELEPHONE CORPORATION
   7  *
   8  *-------------------------------------------------------------------------
   9  */
  10 #include <string.h>
  11
  12 #include "postgres.h"
  13 #include "catalog/pg_collation.h"
  14 #include "catalog/pg_index.h"
  15 #include "commands/prepare.h"
  16 #include "mb/pg_wchar.h"
  17 #include "miscadmin.h"
  18 #include "nodes/nodeFuncs.h"
  19 #include "nodes/params.h"
  20 #include "nodes/relation.h"
  21 #include "optimizer/clauses.h"
  22 #include "optimizer/cost.h"
  23 #include "optimizer/geqo.h"
  24 #include "optimizer/joininfo.h"
  25 #include "optimizer/pathnode.h"
  26 #include "optimizer/paths.h"
  27 #include "optimizer/plancat.h"
  28 #include "optimizer/planner.h"
  29 #include "optimizer/prep.h"
  30 #include "optimizer/restrictinfo.h"
  31 #include "parser/analyze.h"
  32 #include "parser/parsetree.h"
  33 #include "parser/scansup.h"
  34 #include "partitioning/partbounds.h"
  35 #include "tcop/utility.h"
  36 #include "utils/builtins.h"
  37 #include "utils/lsyscache.h"
  38 #include "utils/memutils.h"
  39 #include "utils/rel.h"
  40 #include "utils/snapmgr.h"
  41 #include "utils/syscache.h"
  42 #include "utils/resowner.h"
  43
  44 #include "catalog/pg_class.h"
  45
  46 #include "executor/spi.h"
  47 #include "catalog/pg_type.h"
  48
  49 #include "plpgsql.h"
  50
  51 /* partially copied from pg_stat_statements */
  52 #include "normalize_query.h"
  53
  54 /* PostgreSQL */
  55 #include "access/htup_details.h"
  56
  57 #ifdef PG_MODULE_MAGIC
  58 PG_MODULE_MAGIC;
  59 #endif
  60
  61 #define BLOCK_COMMENT_START             "/*"
  62 #define BLOCK_COMMENT_END               "*/"
  63 #define HINT_COMMENT_KEYWORD    "+"
  64 #define HINT_START                              BLOCK_COMMENT_START HINT_COMMENT_KEYWORD
  65 #define HINT_END                                BLOCK_COMMENT_END
  66
  67 /* hint keywords */
  68 #define HINT_SEQSCAN                    "SeqScan"
  69 #define HINT_INDEXSCAN                  "IndexScan"
  70 #define HINT_INDEXSCANREGEXP    "IndexScanRegexp"
  71 #define HINT_BITMAPSCAN                 "BitmapScan"
  72 #define HINT_BITMAPSCANREGEXP   "BitmapScanRegexp"
  73 #define HINT_TIDSCAN                    "TidScan"
  74 #define HINT_NOSEQSCAN                  "NoSeqScan"
  75 #define HINT_NOINDEXSCAN                "NoIndexScan"
  76 #define HINT_NOBITMAPSCAN               "NoBitmapScan"
  77 #define HINT_NOTIDSCAN                  "NoTidScan"
  78 #define HINT_INDEXONLYSCAN              "IndexOnlyScan"
  79 #define HINT_INDEXONLYSCANREGEXP        "IndexOnlyScanRegexp"
  80 #define HINT_NOINDEXONLYSCAN    "NoIndexOnlyScan"
  81 #define HINT_PARALLEL                   "Parallel"
  82
  83 #define HINT_NESTLOOP                   "NestLoop"
  84 #define HINT_MERGEJOIN                  "MergeJoin"
  85 #define HINT_HASHJOIN                   "HashJoin"
  86 #define HINT_NONESTLOOP                 "NoNestLoop"
  87 #define HINT_NOMERGEJOIN                "NoMergeJoin"
  88 #define HINT_NOHASHJOIN                 "NoHashJoin"
  89 #define HINT_LEADING                    "Leading"
  90 #define HINT_SET                                "Set"
  91 #define HINT_ROWS                               "Rows"
  92
  93 #define HINT_ARRAY_DEFAULT_INITSIZE 8
  94
  95 #define hint_ereport(str, detail) hint_parse_ereport(str, detail)
  96 #define hint_parse_ereport(str, detail) \
  97         do { \
  98                 ereport(pg_hint_plan_parse_message_level,               \
  99                         (errmsg("pg_hint_plan: hint syntax error at or near \"%s\"", (str)), \
 100                          errdetail detail)); \
 101         } while(0)
 102
 103 #define skip_space(str) \
 104         while (isspace(*str)) \
 105                 str++;
 106
 107 enum
 108 {
 109         ENABLE_SEQSCAN = 0x01,
 110         ENABLE_INDEXSCAN = 0x02,
 111         ENABLE_BITMAPSCAN = 0x04,
 112         ENABLE_TIDSCAN = 0x08,
 113         ENABLE_INDEXONLYSCAN = 0x10
 114 } SCAN_TYPE_BITS;
 115
 116 enum
 117 {
 118         ENABLE_NESTLOOP = 0x01,
 119         ENABLE_MERGEJOIN = 0x02,
 120         ENABLE_HASHJOIN = 0x04
 121 } JOIN_TYPE_BITS;
 122
 123 #define ENABLE_ALL_SCAN (ENABLE_SEQSCAN | ENABLE_INDEXSCAN | \
 124                                                  ENABLE_BITMAPSCAN | ENABLE_TIDSCAN | \
 125                                                  ENABLE_INDEXONLYSCAN)
 126 #define ENABLE_ALL_JOIN (ENABLE_NESTLOOP | ENABLE_MERGEJOIN | ENABLE_HASHJOIN)
 127 #define DISABLE_ALL_SCAN 0
 128 #define DISABLE_ALL_JOIN 0
 129
 130 /* hint keyword of enum type*/
 131 typedef enum HintKeyword
 132 {
 133         HINT_KEYWORD_SEQSCAN,
 134         HINT_KEYWORD_INDEXSCAN,
 135         HINT_KEYWORD_INDEXSCANREGEXP,
 136         HINT_KEYWORD_BITMAPSCAN,
 137         HINT_KEYWORD_BITMAPSCANREGEXP,
 138         HINT_KEYWORD_TIDSCAN,
 139         HINT_KEYWORD_NOSEQSCAN,
 140         HINT_KEYWORD_NOINDEXSCAN,
 141         HINT_KEYWORD_NOBITMAPSCAN,
 142         HINT_KEYWORD_NOTIDSCAN,
 143         HINT_KEYWORD_INDEXONLYSCAN,
 144         HINT_KEYWORD_INDEXONLYSCANREGEXP,
 145         HINT_KEYWORD_NOINDEXONLYSCAN,
 146
 147         HINT_KEYWORD_NESTLOOP,
 148         HINT_KEYWORD_MERGEJOIN,
 149         HINT_KEYWORD_HASHJOIN,
 150         HINT_KEYWORD_NONESTLOOP,
 151         HINT_KEYWORD_NOMERGEJOIN,
 152         HINT_KEYWORD_NOHASHJOIN,
 153
 154         HINT_KEYWORD_LEADING,
 155         HINT_KEYWORD_SET,
 156         HINT_KEYWORD_ROWS,
 157         HINT_KEYWORD_PARALLEL,
 158
 159         HINT_KEYWORD_UNRECOGNIZED
 160 } HintKeyword;
 161
 162 #define SCAN_HINT_ACCEPTS_INDEX_NAMES(kw) \
 163         (kw == HINT_KEYWORD_INDEXSCAN ||                        \
 164          kw == HINT_KEYWORD_INDEXSCANREGEXP ||          \
 165          kw == HINT_KEYWORD_INDEXONLYSCAN ||            \
 166          kw == HINT_KEYWORD_INDEXONLYSCANREGEXP ||      \
 167          kw == HINT_KEYWORD_BITMAPSCAN ||                               \
 168          kw == HINT_KEYWORD_BITMAPSCANREGEXP)
 169
 170
 171 typedef struct Hint Hint;
 172 typedef struct HintState HintState;
 173
 174 typedef Hint *(*HintCreateFunction) (const char *hint_str,
 175                                                                          const char *keyword,
 176                                                                          HintKeyword hint_keyword);
 177 typedef void (*HintDeleteFunction) (Hint *hint);
 178 typedef void (*HintDescFunction) (Hint *hint, StringInfo buf, bool nolf);
 179 typedef int (*HintCmpFunction) (const Hint *a, const Hint *b);
 180 typedef const char *(*HintParseFunction) (Hint *hint, HintState *hstate,
 181                                                                                   Query *parse, const char *str);
 182
 183 /* hint types */
 184 #define NUM_HINT_TYPE   6
 185 typedef enum HintType
 186 {
 187         HINT_TYPE_SCAN_METHOD,
 188         HINT_TYPE_JOIN_METHOD,
 189         HINT_TYPE_LEADING,
 190         HINT_TYPE_SET,
 191         HINT_TYPE_ROWS,
 192         HINT_TYPE_PARALLEL
 193 } HintType;
 194
 195 typedef enum HintTypeBitmap
 196 {
 197         HINT_BM_SCAN_METHOD = 1,
 198         HINT_BM_PARALLEL = 2
 199 } HintTypeBitmap;
 200
 201 static const char *HintTypeName[] = {
 202         "scan method",
 203         "join method",
 204         "leading",
 205         "set",
 206         "rows",
 207         "parallel"
 208 };
 209
 210 /* hint status */
 211 typedef enum HintStatus
 212 {
 213         HINT_STATE_NOTUSED = 0,         /* specified relation not used in query */
 214         HINT_STATE_USED,                        /* hint is used */
 215         HINT_STATE_DUPLICATION,         /* specified hint duplication */
 216         HINT_STATE_ERROR                        /* execute error (parse error does not include
 217                                                                  * it) */
 218 } HintStatus;
 219
 220 #define hint_state_enabled(hint) ((hint)->base.state == HINT_STATE_NOTUSED || \
 221                                                                   (hint)->base.state == HINT_STATE_USED)
 222
 223 static unsigned int qno = 0;
 224 static unsigned int msgqno = 0;
 225 static char qnostr[32];
 226 static const char *current_hint_str = NULL;
 227
 228 /*
 229  * However we usually take a hint stirng in post_parse_analyze_hook, we still
 230  * need to do so in planner_hook when client starts query execution from the
 231  * bind message on a prepared query. This variable prevent duplicate and
 232  * sometimes harmful hint string retrieval.
 233  */
 234 static bool current_hint_retrieved = false;
 235
 236 /* common data for all hints. */
 237 struct Hint
 238 {
 239         const char                 *hint_str;           /* must not do pfree */
 240         const char                 *keyword;            /* must not do pfree */
 241         HintKeyword                     hint_keyword;
 242         HintType                        type;
 243         HintStatus                      state;
 244         HintDeleteFunction      delete_func;
 245         HintDescFunction        desc_func;
 246         HintCmpFunction         cmp_func;
 247         HintParseFunction       parse_func;
 248 };
 249
 250 /* scan method hints */
 251 typedef struct ScanMethodHint
 252 {
 253         Hint                    base;
 254         char               *relname;
 255         List               *indexnames;
 256         bool                    regexp;
 257         unsigned char   enforce_mask;
 258 } ScanMethodHint;
 259
 260 typedef struct ParentIndexInfo
 261 {
 262         bool            indisunique;
 263         Oid                     method;
 264         List       *column_names;
 265         char       *expression_str;
 266         Oid                *indcollation;
 267         Oid                *opclass;
 268         int16      *indoption;
 269         char       *indpred_str;
 270 } ParentIndexInfo;
 271
 272 /* join method hints */
 273 typedef struct JoinMethodHint
 274 {
 275         Hint                    base;
 276         int                             nrels;
 277         int                             inner_nrels;
 278         char              **relnames;
 279         unsigned char   enforce_mask;
 280         Relids                  joinrelids;
 281         Relids                  inner_joinrelids;
 282 } JoinMethodHint;
 283
 284 /* join order hints */
 285 typedef struct OuterInnerRels
 286 {
 287         char   *relation;
 288         List   *outer_inner_pair;
 289 } OuterInnerRels;
 290
 291 typedef struct LeadingHint
 292 {
 293         Hint                    base;
 294         List               *relations;  /* relation names specified in Leading hint */
 295         OuterInnerRels *outer_inner;
 296 } LeadingHint;
 297
 298 /* change a run-time parameter hints */
 299 typedef struct SetHint
 300 {
 301         Hint    base;
 302         char   *name;                           /* name of variable */
 303         char   *value;
 304         List   *words;
 305 } SetHint;
 306
 307 /* rows hints */
 308 typedef enum RowsValueType {
 309         RVT_ABSOLUTE,           /* Rows(... #1000) */
 310         RVT_ADD,                        /* Rows(... +1000) */
 311         RVT_SUB,                        /* Rows(... -1000) */
 312         RVT_MULTI,                      /* Rows(... *1.2) */
 313 } RowsValueType;
 314 typedef struct RowsHint
 315 {
 316         Hint                    base;
 317         int                             nrels;
 318         int                             inner_nrels;
 319         char              **relnames;
 320         Relids                  joinrelids;
 321         Relids                  inner_joinrelids;
 322         char               *rows_str;
 323         RowsValueType   value_type;
 324         double                  rows;
 325 } RowsHint;
 326
 327 /* parallel hints */
 328 typedef struct ParallelHint
 329 {
 330         Hint                    base;
 331         char               *relname;
 332         char               *nworkers_str;       /* original string of nworkers */
 333         int                             nworkers;               /* num of workers specified by Worker */
 334         bool                    force_parallel; /* force parallel scan */
 335 } ParallelHint;
 336
 337 /*
 338  * Describes a context of hint processing.
 339  */
 340 struct HintState
 341 {
 342         char               *hint_str;                   /* original hint string */
 343
 344         /* all hint */
 345         int                             nall_hints;                     /* # of valid all hints */
 346         int                             max_all_hints;          /* # of slots for all hints */
 347         Hint              **all_hints;                  /* parsed all hints */
 348
 349         /* # of each hints */
 350         int                             num_hints[NUM_HINT_TYPE];
 351
 352         /* for scan method hints */
 353         ScanMethodHint **scan_hints;            /* parsed scan hints */
 354
 355         /* Initial values of parameters  */
 356         int                             init_scan_mask;         /* enable_* mask */
 357         int                             init_nworkers;          /* max_parallel_workers_per_gather */
 358         /* min_parallel_table_scan_size*/
 359         int                             init_min_para_tablescan_size;
 360         /* min_parallel_index_scan_size*/
 361         int                             init_min_para_indexscan_size;
 362         double                  init_paratup_cost;      /* parallel_tuple_cost */
 363         double                  init_parasetup_cost;/* parallel_setup_cost */
 364
 365         PlannerInfo        *current_root;               /* PlannerInfo for the followings */
 366         Index                   parent_relid;           /* inherit parent of table relid */
 367         ScanMethodHint *parent_scan_hint;       /* scan hint for the parent */
 368         ParallelHint   *parent_parallel_hint; /* parallel hint for the parent */
 369         List               *parent_index_infos; /* list of parent table's index */
 370
 371         JoinMethodHint **join_hints;            /* parsed join hints */
 372         int                             init_join_mask;         /* initial value join parameter */
 373         List              **join_hint_level;
 374         LeadingHint       **leading_hint;               /* parsed Leading hints */
 375         SetHint           **set_hints;                  /* parsed Set hints */
 376         GucContext              context;                        /* which GUC parameters can we set? */
 377         RowsHint          **rows_hints;                 /* parsed Rows hints */
 378         ParallelHint  **parallel_hints;         /* parsed Parallel hints */
 379 };
 380
 381 /*
 382  * Describes a hint parser module which is bound with particular hint keyword.
 383  */
 384 typedef struct HintParser
 385 {
 386         char                       *keyword;
 387         HintCreateFunction      create_func;
 388         HintKeyword                     hint_keyword;
 389 } HintParser;
 390
 391 /* Module callbacks */
 392 void            _PG_init(void);
 393 void            _PG_fini(void);
 394
 395 static void push_hint(HintState *hstate);
 396 static void pop_hint(void);
 397
 398 static void pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query);
 399 static void pg_hint_plan_ProcessUtility(PlannedStmt *pstmt,
 400                                         const char *queryString,
 401                                         ProcessUtilityContext context,
 402                                         ParamListInfo params, QueryEnvironment *queryEnv,
 403                                         DestReceiver *dest, char *completionTag);
 404 static PlannedStmt *pg_hint_plan_planner(Query *parse, int cursorOptions,
 405                                                                                  ParamListInfo boundParams);
 406 static RelOptInfo *pg_hint_plan_join_search(PlannerInfo *root,
 407                                                                                         int levels_needed,
 408                                                                                         List *initial_rels);
 409
 410 /* Scan method hint callbacks */
 411 static Hint *ScanMethodHintCreate(const char *hint_str, const char *keyword,
 412                                                                   HintKeyword hint_keyword);
 413 static void ScanMethodHintDelete(ScanMethodHint *hint);
 414 static void ScanMethodHintDesc(ScanMethodHint *hint, StringInfo buf, bool nolf);
 415 static int ScanMethodHintCmp(const ScanMethodHint *a, const ScanMethodHint *b);
 416 static const char *ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate,
 417                                                                            Query *parse, const char *str);
 418
 419 /* Join method hint callbacks */
 420 static Hint *JoinMethodHintCreate(const char *hint_str, const char *keyword,
 421                                                                   HintKeyword hint_keyword);
 422 static void JoinMethodHintDelete(JoinMethodHint *hint);
 423 static void JoinMethodHintDesc(JoinMethodHint *hint, StringInfo buf, bool nolf);
 424 static int JoinMethodHintCmp(const JoinMethodHint *a, const JoinMethodHint *b);
 425 static const char *JoinMethodHintParse(JoinMethodHint *hint, HintState *hstate,
 426                                                                            Query *parse, const char *str);
 427
 428 /* Leading hint callbacks */
 429 static Hint *LeadingHintCreate(const char *hint_str, const char *keyword,
 430                                                            HintKeyword hint_keyword);
 431 static void LeadingHintDelete(LeadingHint *hint);
 432 static void LeadingHintDesc(LeadingHint *hint, StringInfo buf, bool nolf);
 433 static int LeadingHintCmp(const LeadingHint *a, const LeadingHint *b);
 434 static const char *LeadingHintParse(LeadingHint *hint, HintState *hstate,
 435                                                                         Query *parse, const char *str);
 436
 437 /* Set hint callbacks */
 438 static Hint *SetHintCreate(const char *hint_str, const char *keyword,
 439                                                    HintKeyword hint_keyword);
 440 static void SetHintDelete(SetHint *hint);
 441 static void SetHintDesc(SetHint *hint, StringInfo buf, bool nolf);
 442 static int SetHintCmp(const SetHint *a, const SetHint *b);
 443 static const char *SetHintParse(SetHint *hint, HintState *hstate, Query *parse,
 444                                                                 const char *str);
 445
 446 /* Rows hint callbacks */
 447 static Hint *RowsHintCreate(const char *hint_str, const char *keyword,
 448                                                         HintKeyword hint_keyword);
 449 static void RowsHintDelete(RowsHint *hint);
 450 static void RowsHintDesc(RowsHint *hint, StringInfo buf, bool nolf);
 451 static int RowsHintCmp(const RowsHint *a, const RowsHint *b);
 452 static const char *RowsHintParse(RowsHint *hint, HintState *hstate,
 453                                                                  Query *parse, const char *str);
 454
 455 /* Parallel hint callbacks */
 456 static Hint *ParallelHintCreate(const char *hint_str, const char *keyword,
 457                                                                 HintKeyword hint_keyword);
 458 static void ParallelHintDelete(ParallelHint *hint);
 459 static void ParallelHintDesc(ParallelHint *hint, StringInfo buf, bool nolf);
 460 static int ParallelHintCmp(const ParallelHint *a, const ParallelHint *b);
 461 static const char *ParallelHintParse(ParallelHint *hint, HintState *hstate,
 462                                                                          Query *parse, const char *str);
 463
 464 static void quote_value(StringInfo buf, const char *value);
 465
 466 static const char *parse_quoted_value(const char *str, char **word,
 467                                                                           bool truncate);
 468
 469 RelOptInfo *pg_hint_plan_standard_join_search(PlannerInfo *root,
 470                                                                                           int levels_needed,
 471                                                                                           List *initial_rels);
 472 void pg_hint_plan_join_search_one_level(PlannerInfo *root, int level);
 473 void pg_hint_plan_set_rel_pathlist(PlannerInfo * root, RelOptInfo *rel,
 474                                                                    Index rti, RangeTblEntry *rte);
 475 static void create_plain_partial_paths(PlannerInfo *root,
 476                                                                                                         RelOptInfo *rel);
 477 static void make_rels_by_clause_joins(PlannerInfo *root, RelOptInfo *old_rel,
 478                                                                           ListCell *other_rels);
 479 static void make_rels_by_clauseless_joins(PlannerInfo *root,
 480                                                                                   RelOptInfo *old_rel,
 481                                                                                   ListCell *other_rels);
 482 static bool has_join_restriction(PlannerInfo *root, RelOptInfo *rel);
 483 static void set_plain_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
 484                                                                    RangeTblEntry *rte);
 485 static void set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
 486                                                                         Index rti, RangeTblEntry *rte);
 487 RelOptInfo *pg_hint_plan_make_join_rel(PlannerInfo *root, RelOptInfo *rel1,
 488                                                                            RelOptInfo *rel2);
 489
 490 static void pg_hint_plan_plpgsql_stmt_beg(PLpgSQL_execstate *estate,
 491                                                                                   PLpgSQL_stmt *stmt);
 492 static void pg_hint_plan_plpgsql_stmt_end(PLpgSQL_execstate *estate,
 493                                                                                   PLpgSQL_stmt *stmt);
 494 static void plpgsql_query_erase_callback(ResourceReleasePhase phase,
 495                                                                                  bool isCommit,
 496                                                                                  bool isTopLevel,
 497                                                                                  void *arg);
 498 static int set_config_option_noerror(const char *name, const char *value,
 499                                                   GucContext context, GucSource source,
 500                                                   GucAction action, bool changeVal, int elevel);
 501 static void setup_scan_method_enforcement(ScanMethodHint *scanhint,
 502                                                                                   HintState *state);
 503 static int set_config_int32_option(const char *name, int32 value,
 504                                                                         GucContext context);
 505 static int set_config_double_option(const char *name, double value,
 506                                                                         GucContext context);
 507
 508 /* GUC variables */
 509 static bool     pg_hint_plan_enable_hint = true;
 510 static int debug_level = 0;
 511 static int      pg_hint_plan_parse_message_level = INFO;
 512 static int      pg_hint_plan_debug_message_level = LOG;
 513 /* Default is off, to keep backward compatibility. */
 514 static bool     pg_hint_plan_enable_hint_table = false;
 515
 516 static int plpgsql_recurse_level = 0;           /* PLpgSQL recursion level            */
 517 static int recurse_level = 0;           /* recursion level incl. direct SPI calls */
 518 static int hint_inhibit_level = 0;                      /* Inhibit hinting if this is above 0 */
 519                                                                                         /* (This could not be above 1)        */
 520 static int max_hint_nworkers = -1;              /* Maximum nworkers of Workers hints */
 521
 522 static const struct config_enum_entry parse_messages_level_options[] = {
 523         {"debug", DEBUG2, true},
 524         {"debug5", DEBUG5, false},
 525         {"debug4", DEBUG4, false},
 526         {"debug3", DEBUG3, false},
 527         {"debug2", DEBUG2, false},
 528         {"debug1", DEBUG1, false},
 529         {"log", LOG, false},
 530         {"info", INFO, false},
 531         {"notice", NOTICE, false},
 532         {"warning", WARNING, false},
 533         {"error", ERROR, false},
 534         /*
 535          * {"fatal", FATAL, true},
 536          * {"panic", PANIC, true},
 537          */
 538         {NULL, 0, false}
 539 };
 540
 541 static const struct config_enum_entry parse_debug_level_options[] = {
 542         {"off", 0, false},
 543         {"on", 1, false},
 544         {"detailed", 2, false},
 545         {"verbose", 3, false},
 546         {"0", 0, true},
 547         {"1", 1, true},
 548         {"2", 2, true},
 549         {"3", 3, true},
 550         {"no", 0, true},
 551         {"yes", 1, true},
 552         {"false", 0, true},
 553         {"true", 1, true},
 554         {NULL, 0, false}
 555 };
 556
 557 /* Saved hook values in case of unload */
 558 static post_parse_analyze_hook_type prev_post_parse_analyze_hook = NULL;
 559 static planner_hook_type prev_planner = NULL;
 560 static join_search_hook_type prev_join_search = NULL;
 561 static set_rel_pathlist_hook_type prev_set_rel_pathlist = NULL;
 562 static ProcessUtility_hook_type prev_ProcessUtility_hook = NULL;
 563
 564 /* Hold reference to currently active hint */
 565 static HintState *current_hint_state = NULL;
 566
 567 /*
 568  * List of hint contexts.  We treat the head of the list as the Top of the
 569  * context stack, so current_hint_state always points the first element of this
 570  * list.
 571  */
 572 static List *HintStateStack = NIL;
 573
 574 static const HintParser parsers[] = {
 575         {HINT_SEQSCAN, ScanMethodHintCreate, HINT_KEYWORD_SEQSCAN},
 576         {HINT_INDEXSCAN, ScanMethodHintCreate, HINT_KEYWORD_INDEXSCAN},
 577         {HINT_INDEXSCANREGEXP, ScanMethodHintCreate, HINT_KEYWORD_INDEXSCANREGEXP},
 578         {HINT_BITMAPSCAN, ScanMethodHintCreate, HINT_KEYWORD_BITMAPSCAN},
 579         {HINT_BITMAPSCANREGEXP, ScanMethodHintCreate,
 580          HINT_KEYWORD_BITMAPSCANREGEXP},
 581         {HINT_TIDSCAN, ScanMethodHintCreate, HINT_KEYWORD_TIDSCAN},
 582         {HINT_NOSEQSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOSEQSCAN},
 583         {HINT_NOINDEXSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOINDEXSCAN},
 584         {HINT_NOBITMAPSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOBITMAPSCAN},
 585         {HINT_NOTIDSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOTIDSCAN},
 586         {HINT_INDEXONLYSCAN, ScanMethodHintCreate, HINT_KEYWORD_INDEXONLYSCAN},
 587         {HINT_INDEXONLYSCANREGEXP, ScanMethodHintCreate,
 588          HINT_KEYWORD_INDEXONLYSCANREGEXP},
 589         {HINT_NOINDEXONLYSCAN, ScanMethodHintCreate, HINT_KEYWORD_NOINDEXONLYSCAN},
 590
 591         {HINT_NESTLOOP, JoinMethodHintCreate, HINT_KEYWORD_NESTLOOP},
 592         {HINT_MERGEJOIN, JoinMethodHintCreate, HINT_KEYWORD_MERGEJOIN},
 593         {HINT_HASHJOIN, JoinMethodHintCreate, HINT_KEYWORD_HASHJOIN},
 594         {HINT_NONESTLOOP, JoinMethodHintCreate, HINT_KEYWORD_NONESTLOOP},
 595         {HINT_NOMERGEJOIN, JoinMethodHintCreate, HINT_KEYWORD_NOMERGEJOIN},
 596         {HINT_NOHASHJOIN, JoinMethodHintCreate, HINT_KEYWORD_NOHASHJOIN},
 597
 598         {HINT_LEADING, LeadingHintCreate, HINT_KEYWORD_LEADING},
 599         {HINT_SET, SetHintCreate, HINT_KEYWORD_SET},
 600         {HINT_ROWS, RowsHintCreate, HINT_KEYWORD_ROWS},
 601         {HINT_PARALLEL, ParallelHintCreate, HINT_KEYWORD_PARALLEL},
 602
 603         {NULL, NULL, HINT_KEYWORD_UNRECOGNIZED}
 604 };
 605
 606 PLpgSQL_plugin  plugin_funcs = {
 607         NULL,
 608         NULL,
 609         NULL,
 610         pg_hint_plan_plpgsql_stmt_beg,
 611         pg_hint_plan_plpgsql_stmt_end,
 612         NULL,
 613         NULL,
 614 };
 615
 616 /*
 617  * Module load callbacks
 618  */
 619 void
 620 _PG_init(void)
 621 {
 622         PLpgSQL_plugin  **var_ptr;
 623
 624         /* Define custom GUC variables. */
 625         DefineCustomBoolVariable("pg_hint_plan.enable_hint",
 626                          "Force planner to use plans specified in the hint comment preceding to the query.",
 627                                                          NULL,
 628                                                          &pg_hint_plan_enable_hint,
 629                                                          true,
 630                                                      PGC_USERSET,
 631                                                          0,
 632                                                          NULL,
 633                                                          NULL,
 634                                                          NULL);
 635
 636         DefineCustomEnumVariable("pg_hint_plan.debug_print",
 637                                                          "Logs results of hint parsing.",
 638                                                          NULL,
 639                                                          &debug_level,
 640                                                          false,
 641                                                          parse_debug_level_options,
 642                                                          PGC_USERSET,
 643                                                          0,
 644                                                          NULL,
 645                                                          NULL,
 646                                                          NULL);
 647
 648         DefineCustomEnumVariable("pg_hint_plan.parse_messages",
 649                                                          "Message level of parse errors.",
 650                                                          NULL,
 651                                                          &pg_hint_plan_parse_message_level,
 652                                                          INFO,
 653                                                          parse_messages_level_options,
 654                                                          PGC_USERSET,
 655                                                          0,
 656                                                          NULL,
 657                                                          NULL,
 658                                                          NULL);
 659
 660         DefineCustomEnumVariable("pg_hint_plan.message_level",
 661                                                          "Message level of debug messages.",
 662                                                          NULL,
 663                                                          &pg_hint_plan_debug_message_level,
 664                                                          LOG,
 665                                                          parse_messages_level_options,
 666                                                          PGC_USERSET,
 667                                                          0,
 668                                                          NULL,
 669                                                          NULL,
 670                                                          NULL);
 671
 672         DefineCustomBoolVariable("pg_hint_plan.enable_hint_table",
 673                                                          "Let pg_hint_plan look up the hint table.",
 674                                                          NULL,
 675                                                          &pg_hint_plan_enable_hint_table,
 676                                                          false,
 677                                                          PGC_USERSET,
 678                                                          0,
 679                                                          NULL,
 680                                                          NULL,
 681                                                          NULL);
 682
 683         /* Install hooks. */
 684         prev_post_parse_analyze_hook = post_parse_analyze_hook;
 685         post_parse_analyze_hook = pg_hint_plan_post_parse_analyze;
 686         prev_planner = planner_hook;
 687         planner_hook = pg_hint_plan_planner;
 688         prev_join_search = join_search_hook;
 689         join_search_hook = pg_hint_plan_join_search;
 690         prev_set_rel_pathlist = set_rel_pathlist_hook;
 691         set_rel_pathlist_hook = pg_hint_plan_set_rel_pathlist;
 692         prev_ProcessUtility_hook = ProcessUtility_hook;
 693         ProcessUtility_hook = pg_hint_plan_ProcessUtility;
 694
 695         /* setup PL/pgSQL plugin hook */
 696         var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
 697         *var_ptr = &plugin_funcs;
 698
 699         RegisterResourceReleaseCallback(plpgsql_query_erase_callback, NULL);
 700 }
 701
 702 /*
 703  * Module unload callback
 704  * XXX never called
 705  */
 706 void
 707 _PG_fini(void)
 708 {
 709         PLpgSQL_plugin  **var_ptr;
 710
 711         /* Uninstall hooks. */
 712         post_parse_analyze_hook = prev_post_parse_analyze_hook;
 713         planner_hook = prev_planner;
 714         join_search_hook = prev_join_search;
 715         set_rel_pathlist_hook = prev_set_rel_pathlist;
 716         ProcessUtility_hook = prev_ProcessUtility_hook;
 717
 718         /* uninstall PL/pgSQL plugin hook */
 719         var_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
 720         *var_ptr = NULL;
 721 }
 722
 723 /*
 724  * create and delete functions the hint object
 725  */
 726
 727 static Hint *
 728 ScanMethodHintCreate(const char *hint_str, const char *keyword,
 729                                          HintKeyword hint_keyword)
 730 {
 731         ScanMethodHint *hint;
 732
 733         hint = palloc(sizeof(ScanMethodHint));
 734         hint->base.hint_str = hint_str;
 735         hint->base.keyword = keyword;
 736         hint->base.hint_keyword = hint_keyword;
 737         hint->base.type = HINT_TYPE_SCAN_METHOD;
 738         hint->base.state = HINT_STATE_NOTUSED;
 739         hint->base.delete_func = (HintDeleteFunction) ScanMethodHintDelete;
 740         hint->base.desc_func = (HintDescFunction) ScanMethodHintDesc;
 741         hint->base.cmp_func = (HintCmpFunction) ScanMethodHintCmp;
 742         hint->base.parse_func = (HintParseFunction) ScanMethodHintParse;
 743         hint->relname = NULL;
 744         hint->indexnames = NIL;
 745         hint->regexp = false;
 746         hint->enforce_mask = 0;
 747
 748         return (Hint *) hint;
 749 }
 750
 751 static void
 752 ScanMethodHintDelete(ScanMethodHint *hint)
 753 {
 754         if (!hint)
 755                 return;
 756
 757         if (hint->relname)
 758                 pfree(hint->relname);
 759         list_free_deep(hint->indexnames);
 760         pfree(hint);
 761 }
 762
 763 static Hint *
 764 JoinMethodHintCreate(const char *hint_str, const char *keyword,
 765                                          HintKeyword hint_keyword)
 766 {
 767         JoinMethodHint *hint;
 768
 769         hint = palloc(sizeof(JoinMethodHint));
 770         hint->base.hint_str = hint_str;
 771         hint->base.keyword = keyword;
 772         hint->base.hint_keyword = hint_keyword;
 773         hint->base.type = HINT_TYPE_JOIN_METHOD;
 774         hint->base.state = HINT_STATE_NOTUSED;
 775         hint->base.delete_func = (HintDeleteFunction) JoinMethodHintDelete;
 776         hint->base.desc_func = (HintDescFunction) JoinMethodHintDesc;
 777         hint->base.cmp_func = (HintCmpFunction) JoinMethodHintCmp;
 778         hint->base.parse_func = (HintParseFunction) JoinMethodHintParse;
 779         hint->nrels = 0;
 780         hint->inner_nrels = 0;
 781         hint->relnames = NULL;
 782         hint->enforce_mask = 0;
 783         hint->joinrelids = NULL;
 784         hint->inner_joinrelids = NULL;
 785
 786         return (Hint *) hint;
 787 }
 788
 789 static void
 790 JoinMethodHintDelete(JoinMethodHint *hint)
 791 {
 792         if (!hint)
 793                 return;
 794
 795         if (hint->relnames)
 796         {
 797                 int     i;
 798
 799                 for (i = 0; i < hint->nrels; i++)
 800                         pfree(hint->relnames[i]);
 801                 pfree(hint->relnames);
 802         }
 803
 804         bms_free(hint->joinrelids);
 805         bms_free(hint->inner_joinrelids);
 806         pfree(hint);
 807 }
 808
 809 static Hint *
 810 LeadingHintCreate(const char *hint_str, const char *keyword,
 811                                   HintKeyword hint_keyword)
 812 {
 813         LeadingHint        *hint;
 814
 815         hint = palloc(sizeof(LeadingHint));
 816         hint->base.hint_str = hint_str;
 817         hint->base.keyword = keyword;
 818         hint->base.hint_keyword = hint_keyword;
 819         hint->base.type = HINT_TYPE_LEADING;
 820         hint->base.state = HINT_STATE_NOTUSED;
 821         hint->base.delete_func = (HintDeleteFunction)LeadingHintDelete;
 822         hint->base.desc_func = (HintDescFunction) LeadingHintDesc;
 823         hint->base.cmp_func = (HintCmpFunction) LeadingHintCmp;
 824         hint->base.parse_func = (HintParseFunction) LeadingHintParse;
 825         hint->relations = NIL;
 826         hint->outer_inner = NULL;
 827
 828         return (Hint *) hint;
 829 }
 830
 831 static void
 832 LeadingHintDelete(LeadingHint *hint)
 833 {
 834         if (!hint)
 835                 return;
 836
 837         list_free_deep(hint->relations);
 838         if (hint->outer_inner)
 839                 pfree(hint->outer_inner);
 840         pfree(hint);
 841 }
 842
 843 static Hint *
 844 SetHintCreate(const char *hint_str, const char *keyword,
 845                           HintKeyword hint_keyword)
 846 {
 847         SetHint    *hint;
 848
 849         hint = palloc(sizeof(SetHint));
 850         hint->base.hint_str = hint_str;
 851         hint->base.keyword = keyword;
 852         hint->base.hint_keyword = hint_keyword;
 853         hint->base.type = HINT_TYPE_SET;
 854         hint->base.state = HINT_STATE_NOTUSED;
 855         hint->base.delete_func = (HintDeleteFunction) SetHintDelete;
 856         hint->base.desc_func = (HintDescFunction) SetHintDesc;
 857         hint->base.cmp_func = (HintCmpFunction) SetHintCmp;
 858         hint->base.parse_func = (HintParseFunction) SetHintParse;
 859         hint->name = NULL;
 860         hint->value = NULL;
 861         hint->words = NIL;
 862
 863         return (Hint *) hint;
 864 }
 865
 866 static void
 867 SetHintDelete(SetHint *hint)
 868 {
 869         if (!hint)
 870                 return;
 871
 872         if (hint->name)
 873                 pfree(hint->name);
 874         if (hint->value)
 875                 pfree(hint->value);
 876         if (hint->words)
 877                 list_free(hint->words);
 878         pfree(hint);
 879 }
 880
 881 static Hint *
 882 RowsHintCreate(const char *hint_str, const char *keyword,
 883                            HintKeyword hint_keyword)
 884 {
 885         RowsHint *hint;
 886
 887         hint = palloc(sizeof(RowsHint));
 888         hint->base.hint_str = hint_str;
 889         hint->base.keyword = keyword;
 890         hint->base.hint_keyword = hint_keyword;
 891         hint->base.type = HINT_TYPE_ROWS;
 892         hint->base.state = HINT_STATE_NOTUSED;
 893         hint->base.delete_func = (HintDeleteFunction) RowsHintDelete;
 894         hint->base.desc_func = (HintDescFunction) RowsHintDesc;
 895         hint->base.cmp_func = (HintCmpFunction) RowsHintCmp;
 896         hint->base.parse_func = (HintParseFunction) RowsHintParse;
 897         hint->nrels = 0;
 898         hint->inner_nrels = 0;
 899         hint->relnames = NULL;
 900         hint->joinrelids = NULL;
 901         hint->inner_joinrelids = NULL;
 902         hint->rows_str = NULL;
 903         hint->value_type = RVT_ABSOLUTE;
 904         hint->rows = 0;
 905
 906         return (Hint *) hint;
 907 }
 908
 909 static void
 910 RowsHintDelete(RowsHint *hint)
 911 {
 912         if (!hint)
 913                 return;
 914
 915         if (hint->relnames)
 916         {
 917                 int     i;
 918
 919                 for (i = 0; i < hint->nrels; i++)
 920                         pfree(hint->relnames[i]);
 921                 pfree(hint->relnames);
 922         }
 923
 924         bms_free(hint->joinrelids);
 925         bms_free(hint->inner_joinrelids);
 926         pfree(hint);
 927 }
 928
 929 static Hint *
 930 ParallelHintCreate(const char *hint_str, const char *keyword,
 931                                   HintKeyword hint_keyword)
 932 {
 933         ParallelHint *hint;
 934
 935         hint = palloc(sizeof(ParallelHint));
 936         hint->base.hint_str = hint_str;
 937         hint->base.keyword = keyword;
 938         hint->base.hint_keyword = hint_keyword;
 939         hint->base.type = HINT_TYPE_PARALLEL;
 940         hint->base.state = HINT_STATE_NOTUSED;
 941         hint->base.delete_func = (HintDeleteFunction) ParallelHintDelete;
 942         hint->base.desc_func = (HintDescFunction) ParallelHintDesc;
 943         hint->base.cmp_func = (HintCmpFunction) ParallelHintCmp;
 944         hint->base.parse_func = (HintParseFunction) ParallelHintParse;
 945         hint->relname = NULL;
 946         hint->nworkers = 0;
 947         hint->nworkers_str = "0";
 948
 949         return (Hint *) hint;
 950 }
 951
 952 static void
 953 ParallelHintDelete(ParallelHint *hint)
 954 {
 955         if (!hint)
 956                 return;
 957
 958         if (hint->relname)
 959                 pfree(hint->relname);
 960         pfree(hint);
 961 }
 962
 963
 964 static HintState *
 965 HintStateCreate(void)
 966 {
 967         HintState   *hstate;
 968
 969         hstate = palloc(sizeof(HintState));
 970         hstate->hint_str = NULL;
 971         hstate->nall_hints = 0;
 972         hstate->max_all_hints = 0;
 973         hstate->all_hints = NULL;
 974         memset(hstate->num_hints, 0, sizeof(hstate->num_hints));
 975         hstate->scan_hints = NULL;
 976         hstate->init_scan_mask = 0;
 977         hstate->init_nworkers = 0;
 978         hstate->init_min_para_tablescan_size = 0;
 979         hstate->init_min_para_indexscan_size = 0;
 980         hstate->init_paratup_cost = 0;
 981         hstate->init_parasetup_cost = 0;
 982         hstate->current_root = NULL;
 983         hstate->parent_relid = 0;
 984         hstate->parent_scan_hint = NULL;
 985         hstate->parent_parallel_hint = NULL;
 986         hstate->parent_index_infos = NIL;
 987         hstate->join_hints = NULL;
 988         hstate->init_join_mask = 0;
 989         hstate->join_hint_level = NULL;
 990         hstate->leading_hint = NULL;
 991         hstate->context = superuser() ? PGC_SUSET : PGC_USERSET;
 992         hstate->set_hints = NULL;
 993         hstate->rows_hints = NULL;
 994         hstate->parallel_hints = NULL;
 995
 996         return hstate;
 997 }
 998
 999 static void
1000 HintStateDelete(HintState *hstate)
1001 {
1002         int                     i;
1003
1004         if (!hstate)
1005                 return;
1006
1007         if (hstate->hint_str)
1008                 pfree(hstate->hint_str);
1009
1010         for (i = 0; i < hstate->num_hints[HINT_TYPE_SCAN_METHOD]; i++)
1011                 hstate->all_hints[i]->delete_func(hstate->all_hints[i]);
1012         if (hstate->all_hints)
1013                 pfree(hstate->all_hints);
1014         if (hstate->parent_index_infos)
1015                 list_free(hstate->parent_index_infos);
1016 }
1017
1018 /*
1019  * Copy given value into buf, with quoting with '"' if necessary.
1020  */
1021 static void
1022 quote_value(StringInfo buf, const char *value)
1023 {
1024         bool            need_quote = false;
1025         const char *str;
1026
1027         for (str = value; *str != '\0'; str++)
1028         {
1029                 if (isspace(*str) || *str == '(' || *str == ')' || *str == '"')
1030                 {
1031                         need_quote = true;
1032                         appendStringInfoCharMacro(buf, '"');
1033                         break;
1034                 }
1035         }
1036
1037         for (str = value; *str != '\0'; str++)
1038         {
1039                 if (*str == '"')
1040                         appendStringInfoCharMacro(buf, '"');
1041
1042                 appendStringInfoCharMacro(buf, *str);
1043         }
1044
1045         if (need_quote)
1046                 appendStringInfoCharMacro(buf, '"');
1047 }
1048
1049 static void
1050 ScanMethodHintDesc(ScanMethodHint *hint, StringInfo buf, bool nolf)
1051 {
1052         ListCell   *l;
1053
1054         appendStringInfo(buf, "%s(", hint->base.keyword);
1055         if (hint->relname != NULL)
1056         {
1057                 quote_value(buf, hint->relname);
1058                 foreach(l, hint->indexnames)
1059                 {
1060                         appendStringInfoCharMacro(buf, ' ');
1061                         quote_value(buf, (char *) lfirst(l));
1062                 }
1063         }
1064         appendStringInfoString(buf, ")");
1065         if (!nolf)
1066                 appendStringInfoChar(buf, '\n');
1067 }
1068
1069 static void
1070 JoinMethodHintDesc(JoinMethodHint *hint, StringInfo buf, bool nolf)
1071 {
1072         int     i;
1073
1074         appendStringInfo(buf, "%s(", hint->base.keyword);
1075         if (hint->relnames != NULL)
1076         {
1077                 quote_value(buf, hint->relnames[0]);
1078                 for (i = 1; i < hint->nrels; i++)
1079                 {
1080                         appendStringInfoCharMacro(buf, ' ');
1081                         quote_value(buf, hint->relnames[i]);
1082                 }
1083         }
1084         appendStringInfoString(buf, ")");
1085         if (!nolf)
1086                 appendStringInfoChar(buf, '\n');
1087 }
1088
1089 static void
1090 OuterInnerDesc(OuterInnerRels *outer_inner, StringInfo buf)
1091 {
1092         if (outer_inner->relation == NULL)
1093         {
1094                 bool            is_first;
1095                 ListCell   *l;
1096
1097                 is_first = true;
1098
1099                 appendStringInfoCharMacro(buf, '(');
1100                 foreach(l, outer_inner->outer_inner_pair)
1101                 {
1102                         if (is_first)
1103                                 is_first = false;
1104                         else
1105                                 appendStringInfoCharMacro(buf, ' ');
1106
1107                         OuterInnerDesc(lfirst(l), buf);
1108                 }
1109
1110                 appendStringInfoCharMacro(buf, ')');
1111         }
1112         else
1113                 quote_value(buf, outer_inner->relation);
1114 }
1115
1116 static void
1117 LeadingHintDesc(LeadingHint *hint, StringInfo buf, bool nolf)
1118 {
1119         appendStringInfo(buf, "%s(", HINT_LEADING);
1120         if (hint->outer_inner == NULL)
1121         {
1122                 ListCell   *l;
1123                 bool            is_first;
1124
1125                 is_first = true;
1126
1127                 foreach(l, hint->relations)
1128                 {
1129                         if (is_first)
1130                                 is_first = false;
1131                         else
1132                                 appendStringInfoCharMacro(buf, ' ');
1133
1134                         quote_value(buf, (char *) lfirst(l));
1135                 }
1136         }
1137         else
1138                 OuterInnerDesc(hint->outer_inner, buf);
1139
1140         appendStringInfoString(buf, ")");
1141         if (!nolf)
1142                 appendStringInfoChar(buf, '\n');
1143 }
1144
1145 static void
1146 SetHintDesc(SetHint *hint, StringInfo buf, bool nolf)
1147 {
1148         bool            is_first = true;
1149         ListCell   *l;
1150
1151         appendStringInfo(buf, "%s(", HINT_SET);
1152         foreach(l, hint->words)
1153         {
1154                 if (is_first)
1155                         is_first = false;
1156                 else
1157                         appendStringInfoCharMacro(buf, ' ');
1158
1159                 quote_value(buf, (char *) lfirst(l));
1160         }
1161         appendStringInfo(buf, ")");
1162         if (!nolf)
1163                 appendStringInfoChar(buf, '\n');
1164 }
1165
1166 static void
1167 RowsHintDesc(RowsHint *hint, StringInfo buf, bool nolf)
1168 {
1169         int     i;
1170
1171         appendStringInfo(buf, "%s(", hint->base.keyword);
1172         if (hint->relnames != NULL)
1173         {
1174                 quote_value(buf, hint->relnames[0]);
1175                 for (i = 1; i < hint->nrels; i++)
1176                 {
1177                         appendStringInfoCharMacro(buf, ' ');
1178                         quote_value(buf, hint->relnames[i]);
1179                 }
1180         }
1181         if (hint->rows_str != NULL)
1182                 appendStringInfo(buf, " %s", hint->rows_str);
1183         appendStringInfoString(buf, ")");
1184         if (!nolf)
1185                 appendStringInfoChar(buf, '\n');
1186 }
1187
1188 static void
1189 ParallelHintDesc(ParallelHint *hint, StringInfo buf, bool nolf)
1190 {
1191         appendStringInfo(buf, "%s(", hint->base.keyword);
1192         if (hint->relname != NULL)
1193         {
1194                 quote_value(buf, hint->relname);
1195
1196                 /* number of workers  */
1197                 appendStringInfoCharMacro(buf, ' ');
1198                 quote_value(buf, hint->nworkers_str);
1199                 /* application mode of num of workers */
1200                 appendStringInfoCharMacro(buf, ' ');
1201                 appendStringInfoString(buf,
1202                                                            (hint->force_parallel ? "hard" : "soft"));
1203         }
1204         appendStringInfoString(buf, ")");
1205         if (!nolf)
1206                 appendStringInfoChar(buf, '\n');
1207 }
1208
1209 /*
1210  * Append string which represents all hints in a given state to buf, with
1211  * preceding title with them.
1212  */
1213 static void
1214 desc_hint_in_state(HintState *hstate, StringInfo buf, const char *title,
1215                                    HintStatus state, bool nolf)
1216 {
1217         int     i, nshown;
1218
1219         appendStringInfo(buf, "%s:", title);
1220         if (!nolf)
1221                 appendStringInfoChar(buf, '\n');
1222
1223         nshown = 0;
1224         for (i = 0; i < hstate->nall_hints; i++)
1225         {
1226                 if (hstate->all_hints[i]->state != state)
1227                         continue;
1228
1229                 hstate->all_hints[i]->desc_func(hstate->all_hints[i], buf, nolf);
1230                 nshown++;
1231         }
1232
1233         if (nolf && nshown == 0)
1234                 appendStringInfoString(buf, "(none)");
1235 }
1236
1237 /*
1238  * Dump contents of given hstate to server log with log level LOG.
1239  */
1240 static void
1241 HintStateDump(HintState *hstate)
1242 {
1243         StringInfoData  buf;
1244
1245         if (!hstate)
1246         {
1247                 elog(pg_hint_plan_debug_message_level, "pg_hint_plan:\nno hint");
1248                 return;
1249         }
1250
1251         initStringInfo(&buf);
1252
1253         appendStringInfoString(&buf, "pg_hint_plan:\n");
1254         desc_hint_in_state(hstate, &buf, "used hint", HINT_STATE_USED, false);
1255         desc_hint_in_state(hstate, &buf, "not used hint", HINT_STATE_NOTUSED, false);
1256         desc_hint_in_state(hstate, &buf, "duplication hint", HINT_STATE_DUPLICATION, false);
1257         desc_hint_in_state(hstate, &buf, "error hint", HINT_STATE_ERROR, false);
1258
1259         ereport(pg_hint_plan_debug_message_level,
1260                         (errmsg ("%s", buf.data)));
1261
1262         pfree(buf.data);
1263 }
1264
1265 static void
1266 HintStateDump2(HintState *hstate)
1267 {
1268         StringInfoData  buf;
1269
1270         if (!hstate)
1271         {
1272                 elog(pg_hint_plan_debug_message_level,
1273                          "pg_hint_plan%s: HintStateDump: no hint", qnostr);
1274                 return;
1275         }
1276
1277         initStringInfo(&buf);
1278         appendStringInfo(&buf, "pg_hint_plan%s: HintStateDump: ", qnostr);
1279         desc_hint_in_state(hstate, &buf, "{used hints", HINT_STATE_USED, true);
1280         desc_hint_in_state(hstate, &buf, "}, {not used hints", HINT_STATE_NOTUSED, true);
1281         desc_hint_in_state(hstate, &buf, "}, {duplicate hints", HINT_STATE_DUPLICATION, true);
1282         desc_hint_in_state(hstate, &buf, "}, {error hints", HINT_STATE_ERROR, true);
1283         appendStringInfoChar(&buf, '}');
1284
1285         ereport(pg_hint_plan_debug_message_level,
1286                         (errmsg("%s", buf.data),
1287                          errhidestmt(true),
1288                          errhidecontext(true)));
1289
1290         pfree(buf.data);
1291 }
1292
1293 /*
1294  * compare functions
1295  */
1296
1297 static int
1298 RelnameCmp(const void *a, const void *b)
1299 {
1300         const char *relnamea = *((const char **) a);
1301         const char *relnameb = *((const char **) b);
1302
1303         return strcmp(relnamea, relnameb);
1304 }
1305
1306 static int
1307 ScanMethodHintCmp(const ScanMethodHint *a, const ScanMethodHint *b)
1308 {
1309         return RelnameCmp(&a->relname, &b->relname);
1310 }
1311
1312 static int
1313 JoinMethodHintCmp(const JoinMethodHint *a, const JoinMethodHint *b)
1314 {
1315         int     i;
1316
1317         if (a->nrels != b->nrels)
1318                 return a->nrels - b->nrels;
1319
1320         for (i = 0; i < a->nrels; i++)
1321         {
1322                 int     result;
1323                 if ((result = RelnameCmp(&a->relnames[i], &b->relnames[i])) != 0)
1324                         return result;
1325         }
1326
1327         return 0;
1328 }
1329
1330 static int
1331 LeadingHintCmp(const LeadingHint *a, const LeadingHint *b)
1332 {
1333         return 0;
1334 }
1335
1336 static int
1337 SetHintCmp(const SetHint *a, const SetHint *b)
1338 {
1339         return strcmp(a->name, b->name);
1340 }
1341
1342 static int
1343 RowsHintCmp(const RowsHint *a, const RowsHint *b)
1344 {
1345         int     i;
1346
1347         if (a->nrels != b->nrels)
1348                 return a->nrels - b->nrels;
1349
1350         for (i = 0; i < a->nrels; i++)
1351         {
1352                 int     result;
1353                 if ((result = RelnameCmp(&a->relnames[i], &b->relnames[i])) != 0)
1354                         return result;
1355         }
1356
1357         return 0;
1358 }
1359
1360 static int
1361 ParallelHintCmp(const ParallelHint *a, const ParallelHint *b)
1362 {
1363         return RelnameCmp(&a->relname, &b->relname);
1364 }
1365
1366 static int
1367 HintCmp(const void *a, const void *b)
1368 {
1369         const Hint *hinta = *((const Hint **) a);
1370         const Hint *hintb = *((const Hint **) b);
1371
1372         if (hinta->type != hintb->type)
1373                 return hinta->type - hintb->type;
1374         if (hinta->state == HINT_STATE_ERROR)
1375                 return -1;
1376         if (hintb->state == HINT_STATE_ERROR)
1377                 return 1;
1378         return hinta->cmp_func(hinta, hintb);
1379 }
1380
1381 /*
1382  * Returns byte offset of hint b from hint a.  If hint a was specified before
1383  * b, positive value is returned.
1384  */
1385 static int
1386 HintCmpWithPos(const void *a, const void *b)
1387 {
1388         const Hint *hinta = *((const Hint **) a);
1389         const Hint *hintb = *((const Hint **) b);
1390         int             result;
1391
1392         result = HintCmp(a, b);
1393         if (result == 0)
1394                 result = hinta->hint_str - hintb->hint_str;
1395
1396         return result;
1397 }
1398
1399 /*
1400  * parse functions
1401  */
1402 static const char *
1403 parse_keyword(const char *str, StringInfo buf)
1404 {
1405         skip_space(str);
1406
1407         while (!isspace(*str) && *str != '(' && *str != '\0')
1408                 appendStringInfoCharMacro(buf, *str++);
1409
1410         return str;
1411 }
1412
1413 static const char *
1414 skip_parenthesis(const char *str, char parenthesis)
1415 {
1416         skip_space(str);
1417
1418         if (*str != parenthesis)
1419         {
1420                 if (parenthesis == '(')
1421                         hint_ereport(str, ("Opening parenthesis is necessary."));
1422                 else if (parenthesis == ')')
1423                         hint_ereport(str, ("Closing parenthesis is necessary."));
1424
1425                 return NULL;
1426         }
1427
1428         str++;
1429
1430         return str;
1431 }
1432
1433 /*
1434  * Parse a token from str, and store malloc'd copy into word.  A token can be
1435  * quoted with '"'.  Return value is pointer to unparsed portion of original
1436  * string, or NULL if an error occurred.
1437  *
1438  * Parsed token is truncated within NAMEDATALEN-1 bytes, when truncate is true.
1439  */
1440 static const char *
1441 parse_quoted_value(const char *str, char **word, bool truncate)
1442 {
1443         StringInfoData  buf;
1444         bool                    in_quote;
1445
1446         /* Skip leading spaces. */
1447         skip_space(str);
1448
1449         initStringInfo(&buf);
1450         if (*str == '"')
1451         {
1452                 str++;
1453                 in_quote = true;
1454         }
1455         else
1456                 in_quote = false;
1457
1458         while (true)
1459         {
1460                 if (in_quote)
1461                 {
1462                         /* Double quotation must be closed. */
1463                         if (*str == '\0')
1464                         {
1465                                 pfree(buf.data);
1466                                 hint_ereport(str, ("Unterminated quoted string."));
1467                                 return NULL;
1468                         }
1469
1470                         /*
1471                          * Skip escaped double quotation.
1472                          *
1473                          * We don't allow slash-asterisk and asterisk-slash (delimiters of
1474                          * block comments) to be an object name, so users must specify
1475                          * alias for such object names.
1476                          *
1477                          * Those special names can be allowed if we care escaped slashes
1478                          * and asterisks, but we don't.
1479                          */
1480                         if (*str == '"')
1481                         {
1482                                 str++;
1483                                 if (*str != '"')
1484                                         break;
1485                         }
1486                 }
1487                 else if (isspace(*str) || *str == '(' || *str == ')' || *str == '"' ||
1488                                  *str == '\0')
1489                         break;
1490
1491                 appendStringInfoCharMacro(&buf, *str++);
1492         }
1493
1494         if (buf.len == 0)
1495         {
1496                 hint_ereport(str, ("Zero-length delimited string."));
1497
1498                 pfree(buf.data);
1499
1500                 return NULL;
1501         }
1502
1503         /* Truncate name if it's too long */
1504         if (truncate)
1505                 truncate_identifier(buf.data, strlen(buf.data), true);
1506
1507         *word = buf.data;
1508
1509         return str;
1510 }
1511
1512 static OuterInnerRels *
1513 OuterInnerRelsCreate(char *name, List *outer_inner_list)
1514 {
1515         OuterInnerRels *outer_inner;
1516
1517         outer_inner = palloc(sizeof(OuterInnerRels));
1518         outer_inner->relation = name;
1519         outer_inner->outer_inner_pair = outer_inner_list;
1520
1521         return outer_inner;
1522 }
1523
1524 static const char *
1525 parse_parentheses_Leading_in(const char *str, OuterInnerRels **outer_inner)
1526 {
1527         List   *outer_inner_pair = NIL;
1528
1529         if ((str = skip_parenthesis(str, '(')) == NULL)
1530                 return NULL;
1531
1532         skip_space(str);
1533
1534         /* Store words in parentheses into outer_inner_list. */
1535         while(*str != ')' && *str != '\0')
1536         {
1537                 OuterInnerRels *outer_inner_rels;
1538
1539                 if (*str == '(')
1540                 {
1541                         str = parse_parentheses_Leading_in(str, &outer_inner_rels);
1542                         if (str == NULL)
1543                                 break;
1544                 }
1545                 else
1546                 {
1547                         char   *name;
1548
1549                         if ((str = parse_quoted_value(str, &name, true)) == NULL)
1550                                 break;
1551                         else
1552                                 outer_inner_rels = OuterInnerRelsCreate(name, NIL);
1553                 }
1554
1555                 outer_inner_pair = lappend(outer_inner_pair, outer_inner_rels);
1556                 skip_space(str);
1557         }
1558
1559         if (str == NULL ||
1560                 (str = skip_parenthesis(str, ')')) == NULL)
1561         {
1562                 list_free(outer_inner_pair);
1563                 return NULL;
1564         }
1565
1566         *outer_inner = OuterInnerRelsCreate(NULL, outer_inner_pair);
1567
1568         return str;
1569 }
1570
1571 static const char *
1572 parse_parentheses_Leading(const char *str, List **name_list,
1573         OuterInnerRels **outer_inner)
1574 {
1575         char   *name;
1576         bool    truncate = true;
1577
1578         if ((str = skip_parenthesis(str, '(')) == NULL)
1579                 return NULL;
1580
1581         skip_space(str);
1582         if (*str =='(')
1583         {
1584                 if ((str = parse_parentheses_Leading_in(str, outer_inner)) == NULL)
1585                         return NULL;
1586         }
1587         else
1588         {
1589                 /* Store words in parentheses into name_list. */
1590                 while(*str != ')' && *str != '\0')
1591                 {
1592                         if ((str = parse_quoted_value(str, &name, truncate)) == NULL)
1593                         {
1594                                 list_free(*name_list);
1595                                 return NULL;
1596                         }
1597
1598                         *name_list = lappend(*name_list, name);
1599                         skip_space(str);
1600                 }
1601         }
1602
1603         if ((str = skip_parenthesis(str, ')')) == NULL)
1604                 return NULL;
1605         return str;
1606 }
1607
1608 static const char *
1609 parse_parentheses(const char *str, List **name_list, HintKeyword keyword)
1610 {
1611         char   *name;
1612         bool    truncate = true;
1613
1614         if ((str = skip_parenthesis(str, '(')) == NULL)
1615                 return NULL;
1616
1617         skip_space(str);
1618
1619         /* Store words in parentheses into name_list. */
1620         while(*str != ')' && *str != '\0')
1621         {
1622                 if ((str = parse_quoted_value(str, &name, truncate)) == NULL)
1623                 {
1624                         list_free(*name_list);
1625                         return NULL;
1626                 }
1627
1628                 *name_list = lappend(*name_list, name);
1629                 skip_space(str);
1630
1631                 if (keyword == HINT_KEYWORD_INDEXSCANREGEXP ||
1632                         keyword == HINT_KEYWORD_INDEXONLYSCANREGEXP ||
1633                         keyword == HINT_KEYWORD_BITMAPSCANREGEXP ||
1634                         keyword == HINT_KEYWORD_SET)
1635                 {
1636                         truncate = false;
1637                 }
1638         }
1639
1640         if ((str = skip_parenthesis(str, ')')) == NULL)
1641                 return NULL;
1642         return str;
1643 }
1644
1645 static void
1646 parse_hints(HintState *hstate, Query *parse, const char *str)
1647 {
1648         StringInfoData  buf;
1649         char               *head;
1650
1651         initStringInfo(&buf);
1652         while (*str != '\0')
1653         {
1654                 const HintParser *parser;
1655
1656                 /* in error message, we output the comment including the keyword. */
1657                 head = (char *) str;
1658
1659                 /* parse only the keyword of the hint. */
1660                 resetStringInfo(&buf);
1661                 str = parse_keyword(str, &buf);
1662
1663                 for (parser = parsers; parser->keyword != NULL; parser++)
1664                 {
1665                         char   *keyword = parser->keyword;
1666                         Hint   *hint;
1667
1668                         if (pg_strcasecmp(buf.data, keyword) != 0)
1669                                 continue;
1670
1671                         hint = parser->create_func(head, keyword, parser->hint_keyword);
1672
1673                         /* parser of each hint does parse in a parenthesis. */
1674                         if ((str = hint->parse_func(hint, hstate, parse, str)) == NULL)
1675                         {
1676                                 hint->delete_func(hint);
1677                                 pfree(buf.data);
1678                                 return;
1679                         }
1680
1681                         /*
1682                          * Add hint information into all_hints array.  If we don't have
1683                          * enough space, double the array.
1684                          */
1685                         if (hstate->nall_hints == 0)
1686                         {
1687                                 hstate->max_all_hints = HINT_ARRAY_DEFAULT_INITSIZE;
1688                                 hstate->all_hints = (Hint **)
1689                                         palloc(sizeof(Hint *) * hstate->max_all_hints);
1690                         }
1691                         else if (hstate->nall_hints == hstate->max_all_hints)
1692                         {
1693                                 hstate->max_all_hints *= 2;
1694                                 hstate->all_hints = (Hint **)
1695                                         repalloc(hstate->all_hints,
1696                                                          sizeof(Hint *) * hstate->max_all_hints);
1697                         }
1698
1699                         hstate->all_hints[hstate->nall_hints] = hint;
1700                         hstate->nall_hints++;
1701
1702                         skip_space(str);
1703
1704                         break;
1705                 }
1706
1707                 if (parser->keyword == NULL)
1708                 {
1709                         hint_ereport(head,
1710                                                  ("Unrecognized hint keyword \"%s\".", buf.data));
1711                         pfree(buf.data);
1712                         return;
1713                 }
1714         }
1715
1716         pfree(buf.data);
1717 }
1718
1719
1720 /*
1721  * Get hints from table by client-supplied query string and application name.
1722  */
1723 static const char *
1724 get_hints_from_table(const char *client_query, const char *client_application)
1725 {
1726         const char *search_query =
1727                 "SELECT hints "
1728                 "  FROM hint_plan.hints "
1729                 " WHERE norm_query_string = $1 "
1730                 "   AND ( application_name = $2 "
1731                 "    OR application_name = '' ) "
1732                 " ORDER BY application_name DESC";
1733         static SPIPlanPtr plan = NULL;
1734         char   *hints = NULL;
1735         Oid             argtypes[2] = { TEXTOID, TEXTOID };
1736         Datum   values[2];
1737         char    nulls[2] = {' ', ' '};
1738         text   *qry;
1739         text   *app;
1740
1741         PG_TRY();
1742         {
1743                 bool snapshot_set = false;
1744
1745                 hint_inhibit_level++;
1746
1747                 if (!ActiveSnapshotSet())
1748                 {
1749                         PushActiveSnapshot(GetTransactionSnapshot());
1750                         snapshot_set = true;
1751                 }
1752
1753                 SPI_connect();
1754
1755                 if (plan == NULL)
1756                 {
1757                         SPIPlanPtr      p;
1758                         p = SPI_prepare(search_query, 2, argtypes);
1759                         plan = SPI_saveplan(p);
1760                         SPI_freeplan(p);
1761                 }
1762
1763                 qry = cstring_to_text(client_query);
1764                 app = cstring_to_text(client_application);
1765                 values[0] = PointerGetDatum(qry);
1766                 values[1] = PointerGetDatum(app);
1767
1768                 SPI_execute_plan(plan, values, nulls, true, 1);
1769
1770                 if (SPI_processed > 0)
1771                 {
1772                         char    *buf;
1773
1774                         hints = SPI_getvalue(SPI_tuptable->vals[0],
1775                                                                  SPI_tuptable->tupdesc, 1);
1776                         /*
1777                          * Here we use SPI_palloc to ensure that hints string is valid even
1778                          * after SPI_finish call.  We can't use simple palloc because it
1779                          * allocates memory in SPI's context and that context is deleted in
1780                          * SPI_finish.
1781                          */
1782                         buf = SPI_palloc(strlen(hints) + 1);
1783                         strcpy(buf, hints);
1784                         hints = buf;
1785                 }
1786
1787                 SPI_finish();
1788
1789                 if (snapshot_set)
1790                         PopActiveSnapshot();
1791
1792                 hint_inhibit_level--;
1793         }
1794         PG_CATCH();
1795         {
1796                 hint_inhibit_level--;
1797                 PG_RE_THROW();
1798         }
1799         PG_END_TRY();
1800
1801         return hints;
1802 }
1803
1804 /*
1805  * Get client-supplied query string. Addtion to that the jumbled query is
1806  * supplied if the caller requested. From the restriction of JumbleQuery, some
1807  * kind of query needs special amendments. Reutrns NULL if this query doesn't
1808  * change the current hint. This function returns NULL also when something
1809  * wrong has happend and let the caller continue using the current hints.
1810  */
1811 static const char *
1812 get_query_string(ParseState *pstate, Query *query, Query **jumblequery)
1813 {
1814         const char *p = debug_query_string;
1815
1816         /*
1817          * If debug_query_string is set, it is the top level statement. But in some
1818          * cases we reach here with debug_query_string set NULL for example in the
1819          * case of DESCRIBE message handling or EXECUTE command. We may still see a
1820          * candidate top-level query in pstate in the case.
1821          */
1822         if (pstate && pstate->p_sourcetext)
1823                 p = pstate->p_sourcetext;
1824
1825         /* We don't see a query string, return NULL */
1826         if (!p)
1827                 return NULL;
1828
1829         if (jumblequery != NULL)
1830                 *jumblequery = query;
1831
1832         if (query->commandType == CMD_UTILITY)
1833         {
1834                 Query *target_query = (Query *)query->utilityStmt;
1835
1836                 /*
1837                  * Some CMD_UTILITY statements have a subquery that we can hint on.
1838                  * Since EXPLAIN can be placed before other kind of utility statements
1839                  * and EXECUTE can be contained other kind of utility statements, these
1840                  * conditions are not mutually exclusive and should be considered in
1841                  * this order.
1842                  */
1843                 if (IsA(target_query, ExplainStmt))
1844                 {
1845                         ExplainStmt *stmt = (ExplainStmt *)target_query;
1846
1847                         Assert(IsA(stmt->query, Query));
1848                         target_query = (Query *)stmt->query;
1849
1850                         /* strip out the top-level query for further processing */
1851                         if (target_query->commandType == CMD_UTILITY &&
1852                                 target_query->utilityStmt != NULL)
1853                                 target_query = (Query *)target_query->utilityStmt;
1854                 }
1855
1856                 if (IsA(target_query, DeclareCursorStmt))
1857                 {
1858                         DeclareCursorStmt *stmt = (DeclareCursorStmt *)target_query;
1859                         Query *query = (Query *)stmt->query;
1860
1861                         /* the target must be CMD_SELECT in this case */
1862                         Assert(IsA(query, Query) && query->commandType == CMD_SELECT);
1863                         target_query = query;
1864                 }
1865
1866                 if (IsA(target_query, CreateTableAsStmt))
1867                 {
1868                         CreateTableAsStmt  *stmt = (CreateTableAsStmt *) target_query;
1869
1870                         Assert(IsA(stmt->query, Query));
1871                         target_query = (Query *) stmt->query;
1872
1873                         /* strip out the top-level query for further processing */
1874                         if (target_query->commandType == CMD_UTILITY &&
1875                                 target_query->utilityStmt != NULL)
1876                                 target_query = (Query *)target_query->utilityStmt;
1877                 }
1878
1879                 if (IsA(target_query, ExecuteStmt))
1880                 {
1881                         /*
1882                          * Use the prepared query for EXECUTE. The Query for jumble
1883                          * also replaced with the corresponding one.
1884                          */
1885                         ExecuteStmt *stmt = (ExecuteStmt *)target_query;
1886                         PreparedStatement  *entry;
1887
1888                         entry = FetchPreparedStatement(stmt->name, true);
1889
1890                         if (entry->plansource->is_valid)
1891                         {
1892                                 p = entry->plansource->query_string;
1893                                 target_query = (Query *) linitial (entry->plansource->query_list);
1894                         }
1895                         else
1896                         {
1897                                 /* igonre the hint for EXECUTE if invalidated */
1898                                 p = NULL;
1899                                 target_query = NULL;
1900                         }
1901                 }
1902
1903                 /* JumbleQuery accespts only a non-utility Query */
1904                 if (target_query &&
1905                         (!IsA(target_query, Query) ||
1906                          target_query->utilityStmt != NULL))
1907                         target_query = NULL;
1908
1909                 if (jumblequery)
1910                         *jumblequery = target_query;
1911         }
1912         /*
1913          * Return NULL if pstate is not of top-level query.  We don't need this
1914          * when jumble info is not requested or cannot do this when pstate is NULL.
1915          */
1916         else if (!jumblequery && pstate && pstate->p_sourcetext != p &&
1917                          strcmp(pstate->p_sourcetext, p) != 0)
1918                 p = NULL;
1919
1920         return p;
1921 }
1922
1923 /*
1924  * Get hints from the head block comment in client-supplied query string.
1925  */
1926 static const char *
1927 get_hints_from_comment(const char *p)
1928 {
1929         const char *hint_head;
1930         char       *head;
1931         char       *tail;
1932         int                     len;
1933
1934         if (p == NULL)
1935                 return NULL;
1936
1937         /* extract query head comment. */
1938         hint_head = strstr(p, HINT_START);
1939         if (hint_head == NULL)
1940                 return NULL;
1941         for (;p < hint_head; p++)
1942         {
1943                 /*
1944                  * Allow these characters precedes hint comment:
1945                  *   - digits
1946                  *   - alphabets which are in ASCII range
1947                  *   - space, tabs and new-lines
1948                  *   - underscores, for identifier
1949                  *   - commas, for SELECT clause, EXPLAIN and PREPARE
1950                  *   - parentheses, for EXPLAIN and PREPARE
1951                  *
1952                  * Note that we don't use isalpha() nor isalnum() in ctype.h here to
1953                  * avoid behavior which depends on locale setting.
1954                  */
1955                 if (!(*p >= '0' && *p <= '9') &&
1956                         !(*p >= 'A' && *p <= 'Z') &&
1957                         !(*p >= 'a' && *p <= 'z') &&
1958                         !isspace(*p) &&
1959                         *p != '_' &&
1960                         *p != ',' &&
1961                         *p != '(' && *p != ')')
1962                         return NULL;
1963         }
1964
1965         len = strlen(HINT_START);
1966         head = (char *) p;
1967         p += len;
1968         skip_space(p);
1969
1970         /* find hint end keyword. */
1971         if ((tail = strstr(p, HINT_END)) == NULL)
1972         {
1973                 hint_ereport(head, ("Unterminated block comment."));
1974                 return NULL;
1975         }
1976
1977         /* We don't support nested block comments. */
1978         if ((head = strstr(p, BLOCK_COMMENT_START)) != NULL && head < tail)
1979         {
1980                 hint_ereport(head, ("Nested block comments are not supported."));
1981                 return NULL;
1982         }
1983
1984         /* Make a copy of hint. */
1985         len = tail - p;
1986         head = palloc(len + 1);
1987         memcpy(head, p, len);
1988         head[len] = '\0';
1989         p = head;
1990
1991         return p;
1992 }
1993
1994 /*
1995  * Parse hints that got, create hint struct from parse tree and parse hints.
1996  */
1997 static HintState *
1998 create_hintstate(Query *parse, const char *hints)
1999 {
2000         const char *p;
2001         int                     i;
2002         HintState   *hstate;
2003
2004         if (hints == NULL)
2005                 return NULL;
2006
2007         /* -1 means that no Parallel hint is specified. */
2008         max_hint_nworkers = -1;
2009
2010         p = hints;
2011         hstate = HintStateCreate();
2012         hstate->hint_str = (char *) hints;
2013
2014         /* parse each hint. */
2015         parse_hints(hstate, parse, p);
2016
2017         /* When nothing specified a hint, we free HintState and returns NULL. */
2018         if (hstate->nall_hints == 0)
2019         {
2020                 HintStateDelete(hstate);
2021                 return NULL;
2022         }
2023
2024         /* Sort hints in order of original position. */
2025         qsort(hstate->all_hints, hstate->nall_hints, sizeof(Hint *),
2026                   HintCmpWithPos);
2027
2028         /* Count number of hints per hint-type. */
2029         for (i = 0; i < hstate->nall_hints; i++)
2030         {
2031                 Hint   *cur_hint = hstate->all_hints[i];
2032                 hstate->num_hints[cur_hint->type]++;
2033         }
2034
2035         /*
2036          * If an object (or a set of objects) has multiple hints of same hint-type,
2037          * only the last hint is valid and others are ignored in planning.
2038          * Hints except the last are marked as 'duplicated' to remember the order.
2039          */
2040         for (i = 0; i < hstate->nall_hints - 1; i++)
2041         {
2042                 Hint   *cur_hint = hstate->all_hints[i];
2043                 Hint   *next_hint = hstate->all_hints[i + 1];
2044
2045                 /*
2046                  * Leading hint is marked as 'duplicated' in transform_join_hints.
2047                  */
2048                 if (cur_hint->type == HINT_TYPE_LEADING &&
2049                         next_hint->type == HINT_TYPE_LEADING)
2050                         continue;
2051
2052                 /*
2053                  * Note that we need to pass addresses of hint pointers, because
2054                  * HintCmp is designed to sort array of Hint* by qsort.
2055                  */
2056                 if (HintCmp(&cur_hint, &next_hint) == 0)
2057                 {
2058                         hint_ereport(cur_hint->hint_str,
2059                                                  ("Conflict %s hint.", HintTypeName[cur_hint->type]));
2060                         cur_hint->state = HINT_STATE_DUPLICATION;
2061                 }
2062         }
2063
2064         /*
2065          * Make sure that per-type array pointers point proper position in the
2066          * array which consists of all hints.
2067          */
2068         hstate->scan_hints = (ScanMethodHint **) hstate->all_hints;
2069         hstate->join_hints = (JoinMethodHint **) (hstate->scan_hints +
2070                 hstate->num_hints[HINT_TYPE_SCAN_METHOD]);
2071         hstate->leading_hint = (LeadingHint **) (hstate->join_hints +
2072                 hstate->num_hints[HINT_TYPE_JOIN_METHOD]);
2073         hstate->set_hints = (SetHint **) (hstate->leading_hint +
2074                 hstate->num_hints[HINT_TYPE_LEADING]);
2075         hstate->rows_hints = (RowsHint **) (hstate->set_hints +
2076                 hstate->num_hints[HINT_TYPE_SET]);
2077         hstate->parallel_hints = (ParallelHint **) (hstate->rows_hints +
2078                 hstate->num_hints[HINT_TYPE_ROWS]);
2079
2080         return hstate;
2081 }
2082
2083 /*
2084  * Parse inside of parentheses of scan-method hints.
2085  */
2086 static const char *
2087 ScanMethodHintParse(ScanMethodHint *hint, HintState *hstate, Query *parse,
2088                                         const char *str)
2089 {
2090         const char         *keyword = hint->base.keyword;
2091         HintKeyword             hint_keyword = hint->base.hint_keyword;
2092         List               *name_list = NIL;
2093         int                             length;
2094
2095         if ((str = parse_parentheses(str, &name_list, hint_keyword)) == NULL)
2096                 return NULL;
2097
2098         /* Parse relation name and index name(s) if given hint accepts. */
2099         length = list_length(name_list);
2100
2101         /* at least twp parameters required */
2102         if (length < 1)
2103         {
2104                 hint_ereport(str,
2105                                          ("%s hint requires a relation.",  hint->base.keyword));
2106                 hint->base.state = HINT_STATE_ERROR;
2107                 return str;
2108         }
2109
2110         hint->relname = linitial(name_list);
2111         hint->indexnames = list_delete_first(name_list);
2112
2113         /* check whether the hint accepts index name(s) */
2114         if (length > 1 && !SCAN_HINT_ACCEPTS_INDEX_NAMES(hint_keyword))
2115         {
2116                 hint_ereport(str,
2117                                          ("%s hint accepts only one relation.",
2118                                           hint->base.keyword));
2119                 hint->base.state = HINT_STATE_ERROR;
2120                 return str;
2121         }
2122
2123         /* Set a bit for specified hint. */
2124         switch (hint_keyword)
2125         {
2126                 case HINT_KEYWORD_SEQSCAN:
2127                         hint->enforce_mask = ENABLE_SEQSCAN;
2128                         break;
2129                 case HINT_KEYWORD_INDEXSCAN:
2130                         hint->enforce_mask = ENABLE_INDEXSCAN;
2131                         break;
2132                 case HINT_KEYWORD_INDEXSCANREGEXP:
2133                         hint->enforce_mask = ENABLE_INDEXSCAN;
2134                         hint->regexp = true;
2135                         break;
2136                 case HINT_KEYWORD_BITMAPSCAN:
2137                         hint->enforce_mask = ENABLE_BITMAPSCAN;
2138                         break;
2139                 case HINT_KEYWORD_BITMAPSCANREGEXP:
2140                         hint->enforce_mask = ENABLE_BITMAPSCAN;
2141                         hint->regexp = true;
2142                         break;
2143                 case HINT_KEYWORD_TIDSCAN:
2144                         hint->enforce_mask = ENABLE_TIDSCAN;
2145                         break;
2146                 case HINT_KEYWORD_NOSEQSCAN:
2147                         hint->enforce_mask = ENABLE_ALL_SCAN ^ ENABLE_SEQSCAN;
2148                         break;
2149                 case HINT_KEYWORD_NOINDEXSCAN:
2150                         hint->enforce_mask = ENABLE_ALL_SCAN ^ ENABLE_INDEXSCAN;
2151                         break;
2152                 case HINT_KEYWORD_NOBITMAPSCAN:
2153                         hint->enforce_mask = ENABLE_ALL_SCAN ^ ENABLE_BITMAPSCAN;
2154                         break;
2155                 case HINT_KEYWORD_NOTIDSCAN:
2156                         hint->enforce_mask = ENABLE_ALL_SCAN ^ ENABLE_TIDSCAN;
2157                         break;
2158                 case HINT_KEYWORD_INDEXONLYSCAN:
2159                         hint->enforce_mask = ENABLE_INDEXSCAN | ENABLE_INDEXONLYSCAN;
2160                         break;
2161                 case HINT_KEYWORD_INDEXONLYSCANREGEXP:
2162                         hint->enforce_mask = ENABLE_INDEXSCAN | ENABLE_INDEXONLYSCAN;
2163                         hint->regexp = true;
2164                         break;
2165                 case HINT_KEYWORD_NOINDEXONLYSCAN:
2166                         hint->enforce_mask = ENABLE_ALL_SCAN ^ ENABLE_INDEXONLYSCAN;
2167                         break;
2168                 default:
2169                         hint_ereport(str, ("Unrecognized hint keyword \"%s\".", keyword));
2170                         return NULL;
2171                         break;
2172         }
2173
2174         return str;
2175 }
2176
2177 static const char *
2178 JoinMethodHintParse(JoinMethodHint *hint, HintState *hstate, Query *parse,
2179                                         const char *str)
2180 {
2181         const char         *keyword = hint->base.keyword;
2182         HintKeyword             hint_keyword = hint->base.hint_keyword;
2183         List               *name_list = NIL;
2184
2185         if ((str = parse_parentheses(str, &name_list, hint_keyword)) == NULL)
2186                 return NULL;
2187
2188         hint->nrels = list_length(name_list);
2189
2190         if (hint->nrels > 0)
2191         {
2192                 ListCell   *l;
2193                 int                     i = 0;
2194
2195                 /*
2196                  * Transform relation names from list to array to sort them with qsort
2197                  * after.
2198                  */
2199                 hint->relnames = palloc(sizeof(char *) * hint->nrels);
2200                 foreach (l, name_list)
2201                 {
2202                         hint->relnames[i] = lfirst(l);
2203                         i++;
2204                 }
2205         }
2206
2207         list_free(name_list);
2208
2209         /* A join hint requires at least two relations */
2210         if (hint->nrels < 2)
2211         {
2212                 hint_ereport(str,
2213                                          ("%s hint requires at least two relations.",
2214                                           hint->base.keyword));
2215                 hint->base.state = HINT_STATE_ERROR;
2216                 return str;
2217         }
2218
2219         /* Sort hints in alphabetical order of relation names. */
2220         qsort(hint->relnames, hint->nrels, sizeof(char *), RelnameCmp);
2221
2222         switch (hint_keyword)
2223         {
2224                 case HINT_KEYWORD_NESTLOOP:
2225                         hint->enforce_mask = ENABLE_NESTLOOP;
2226                         break;
2227                 case HINT_KEYWORD_MERGEJOIN:
2228                         hint->enforce_mask = ENABLE_MERGEJOIN;
2229                         break;
2230                 case HINT_KEYWORD_HASHJOIN:
2231                         hint->enforce_mask = ENABLE_HASHJOIN;
2232                         break;
2233                 case HINT_KEYWORD_NONESTLOOP:
2234                         hint->enforce_mask = ENABLE_ALL_JOIN ^ ENABLE_NESTLOOP;
2235                         break;
2236                 case HINT_KEYWORD_NOMERGEJOIN:
2237                         hint->enforce_mask = ENABLE_ALL_JOIN ^ ENABLE_MERGEJOIN;
2238                         break;
2239                 case HINT_KEYWORD_NOHASHJOIN:
2240                         hint->enforce_mask = ENABLE_ALL_JOIN ^ ENABLE_HASHJOIN;
2241                         break;
2242                 default:
2243                         hint_ereport(str, ("Unrecognized hint keyword \"%s\".", keyword));
2244                         return NULL;
2245                         break;
2246         }
2247
2248         return str;
2249 }
2250
2251 static bool
2252 OuterInnerPairCheck(OuterInnerRels *outer_inner)
2253 {
2254         ListCell *l;
2255         if (outer_inner->outer_inner_pair == NIL)
2256         {
2257                 if (outer_inner->relation)
2258                         return true;
2259                 else
2260                         return false;
2261         }
2262
2263         if (list_length(outer_inner->outer_inner_pair) == 2)
2264         {
2265                 foreach(l, outer_inner->outer_inner_pair)
2266                 {
2267                         if (!OuterInnerPairCheck(lfirst(l)))
2268                                 return false;
2269                 }
2270         }
2271         else
2272                 return false;
2273
2274         return true;
2275 }
2276
2277 static List *
2278 OuterInnerList(OuterInnerRels *outer_inner)
2279 {
2280         List               *outer_inner_list = NIL;
2281         ListCell           *l;
2282         OuterInnerRels *outer_inner_rels;
2283
2284         foreach(l, outer_inner->outer_inner_pair)
2285         {
2286                 outer_inner_rels = (OuterInnerRels *)(lfirst(l));
2287
2288                 if (outer_inner_rels->relation != NULL)
2289                         outer_inner_list = lappend(outer_inner_list,
2290                                                                            outer_inner_rels->relation);
2291                 else
2292                         outer_inner_list = list_concat(outer_inner_list,
2293                                                                                    OuterInnerList(outer_inner_rels));
2294         }
2295         return outer_inner_list;
2296 }
2297
2298 static const char *
2299 LeadingHintParse(LeadingHint *hint, HintState *hstate, Query *parse,
2300                                  const char *str)
2301 {
2302         List               *name_list = NIL;
2303         OuterInnerRels *outer_inner = NULL;
2304
2305         if ((str = parse_parentheses_Leading(str, &name_list, &outer_inner)) ==
2306                 NULL)
2307                 return NULL;
2308
2309         if (outer_inner != NULL)
2310                 name_list = OuterInnerList(outer_inner);
2311
2312         hint->relations = name_list;
2313         hint->outer_inner = outer_inner;
2314
2315         /* A Leading hint requires at least two relations */
2316         if ( hint->outer_inner == NULL && list_length(hint->relations) < 2)
2317         {
2318                 hint_ereport(hint->base.hint_str,
2319                                          ("%s hint requires at least two relations.",
2320                                           HINT_LEADING));
2321                 hint->base.state = HINT_STATE_ERROR;
2322         }
2323         else if (hint->outer_inner != NULL &&
2324                          !OuterInnerPairCheck(hint->outer_inner))
2325         {
2326                 hint_ereport(hint->base.hint_str,
2327                                          ("%s hint requires two sets of relations when parentheses nests.",
2328                                           HINT_LEADING));
2329                 hint->base.state = HINT_STATE_ERROR;
2330         }
2331
2332         return str;
2333 }
2334
2335 static const char *
2336 SetHintParse(SetHint *hint, HintState *hstate, Query *parse, const char *str)
2337 {
2338         List   *name_list = NIL;
2339
2340         if ((str = parse_parentheses(str, &name_list, hint->base.hint_keyword))
2341                 == NULL)
2342                 return NULL;
2343
2344         hint->words = name_list;
2345
2346         /* We need both name and value to set GUC parameter. */
2347         if (list_length(name_list) == 2)
2348         {
2349                 hint->name = linitial(name_list);
2350                 hint->value = lsecond(name_list);
2351         }
2352         else
2353         {
2354                 hint_ereport(hint->base.hint_str,
2355                                          ("%s hint requires name and value of GUC parameter.",
2356                                           HINT_SET));
2357                 hint->base.state = HINT_STATE_ERROR;
2358         }
2359
2360         return str;
2361 }
2362
2363 static const char *
2364 RowsHintParse(RowsHint *hint, HintState *hstate, Query *parse,
2365                           const char *str)
2366 {
2367         HintKeyword             hint_keyword = hint->base.hint_keyword;
2368         List               *name_list = NIL;
2369         char               *rows_str;
2370         char               *end_ptr;
2371         ListCell   *l;
2372         int                     i = 0;
2373
2374         if ((str = parse_parentheses(str, &name_list, hint_keyword)) == NULL)
2375                 return NULL;
2376
2377         /* Last element must be rows specification */
2378         hint->nrels = list_length(name_list) - 1;
2379
2380         if (hint->nrels < 1)
2381         {
2382                 hint_ereport(str,
2383                                          ("%s hint needs at least one relation followed by one correction term.",
2384                                           hint->base.keyword));
2385                 hint->base.state = HINT_STATE_ERROR;
2386
2387                 return str;
2388         }
2389
2390
2391         /*
2392          * Transform relation names from list to array to sort them with qsort
2393          * after.
2394          */
2395         hint->relnames = palloc(sizeof(char *) * hint->nrels);
2396         foreach (l, name_list)
2397         {
2398                 if (hint->nrels <= i)
2399                         break;
2400                 hint->relnames[i] = lfirst(l);
2401                 i++;
2402         }
2403
2404         /* Retieve rows estimation */
2405         rows_str = list_nth(name_list, hint->nrels);
2406         hint->rows_str = rows_str;              /* store as-is for error logging */
2407         if (rows_str[0] == '#')
2408         {
2409                 hint->value_type = RVT_ABSOLUTE;
2410                 rows_str++;
2411         }
2412         else if (rows_str[0] == '+')
2413         {
2414                 hint->value_type = RVT_ADD;
2415                 rows_str++;
2416         }
2417         else if (rows_str[0] == '-')
2418         {
2419                 hint->value_type = RVT_SUB;
2420                 rows_str++;
2421         }
2422         else if (rows_str[0] == '*')
2423         {
2424                 hint->value_type = RVT_MULTI;
2425                 rows_str++;
2426         }
2427         else
2428         {
2429                 hint_ereport(rows_str, ("Unrecognized rows value type notation."));
2430                 hint->base.state = HINT_STATE_ERROR;
2431                 return str;
2432         }
2433         hint->rows = strtod(rows_str, &end_ptr);
2434         if (*end_ptr)
2435         {
2436                 hint_ereport(rows_str,
2437                                          ("%s hint requires valid number as rows estimation.",
2438                                           hint->base.keyword));
2439                 hint->base.state = HINT_STATE_ERROR;
2440                 return str;
2441         }
2442
2443         /* A join hint requires at least two relations */
2444         if (hint->nrels < 2)
2445         {
2446                 hint_ereport(str,
2447                                          ("%s hint requires at least two relations.",
2448                                           hint->base.keyword));
2449                 hint->base.state = HINT_STATE_ERROR;
2450                 return str;
2451         }
2452
2453         list_free(name_list);
2454
2455         /* Sort relnames in alphabetical order. */
2456         qsort(hint->relnames, hint->nrels, sizeof(char *), RelnameCmp);
2457
2458         return str;
2459 }
2460
2461 static const char *
2462 ParallelHintParse(ParallelHint *hint, HintState *hstate, Query *parse,
2463                                   const char *str)
2464 {
2465         HintKeyword             hint_keyword = hint->base.hint_keyword;
2466         List               *name_list = NIL;
2467         int                             length;
2468         char   *end_ptr;
2469         int             nworkers;
2470         bool    force_parallel = false;
2471
2472         if ((str = parse_parentheses(str, &name_list, hint_keyword)) == NULL)
2473                 return NULL;
2474
2475         /* Parse relation name and index name(s) if given hint accepts. */
2476         length = list_length(name_list);
2477
2478         if (length < 2 || length > 3)
2479         {
2480                 hint_ereport(")",
2481                                          ("wrong number of arguments (%d): %s",
2482                                           length,  hint->base.keyword));
2483                 hint->base.state = HINT_STATE_ERROR;
2484                 return str;
2485         }
2486
2487         hint->relname = linitial(name_list);
2488
2489         /* The second parameter is number of workers */
2490         hint->nworkers_str = list_nth(name_list, 1);
2491         nworkers = strtod(hint->nworkers_str, &end_ptr);
2492         if (*end_ptr || nworkers < 0 || nworkers > max_worker_processes)
2493         {
2494                 if (*end_ptr)
2495                         hint_ereport(hint->nworkers_str,
2496                                                  ("number of workers must be a number: %s",
2497                                                   hint->base.keyword));
2498                 else if (nworkers < 0)
2499                         hint_ereport(hint->nworkers_str,
2500                                                  ("number of workers must be positive: %s",
2501                                                   hint->base.keyword));
2502                 else if (nworkers > max_worker_processes)
2503                         hint_ereport(hint->nworkers_str,
2504                                                  ("number of workers = %d is larger than max_worker_processes(%d): %s",
2505                                                   nworkers, max_worker_processes, hint->base.keyword));
2506
2507                 hint->base.state = HINT_STATE_ERROR;
2508         }
2509
2510         hint->nworkers = nworkers;
2511
2512         /* optional third parameter is specified */
2513         if (length == 3)
2514         {
2515                 const char *modeparam = (const char *)list_nth(name_list, 2);
2516                 if (pg_strcasecmp(modeparam, "hard") == 0)
2517                         force_parallel = true;
2518                 else if (pg_strcasecmp(modeparam, "soft") != 0)
2519                 {
2520                         hint_ereport(modeparam,
2521                                                  ("enforcement must be soft or hard: %s",
2522                                                          hint->base.keyword));
2523                         hint->base.state = HINT_STATE_ERROR;
2524                 }
2525         }
2526
2527         hint->force_parallel = force_parallel;
2528
2529         if (hint->base.state != HINT_STATE_ERROR &&
2530                 nworkers > max_hint_nworkers)
2531                 max_hint_nworkers = nworkers;
2532
2533         return str;
2534 }
2535
2536 /*
2537  * set GUC parameter functions
2538  */
2539
2540 static int
2541 get_current_scan_mask()
2542 {
2543         int mask = 0;
2544
2545         if (enable_seqscan)
2546                 mask |= ENABLE_SEQSCAN;
2547         if (enable_indexscan)
2548                 mask |= ENABLE_INDEXSCAN;
2549         if (enable_bitmapscan)
2550                 mask |= ENABLE_BITMAPSCAN;
2551         if (enable_tidscan)
2552                 mask |= ENABLE_TIDSCAN;
2553         if (enable_indexonlyscan)
2554                 mask |= ENABLE_INDEXONLYSCAN;
2555
2556         return mask;
2557 }
2558
2559 static int
2560 get_current_join_mask()
2561 {
2562         int mask = 0;
2563
2564         if (enable_nestloop)
2565                 mask |= ENABLE_NESTLOOP;
2566         if (enable_mergejoin)
2567                 mask |= ENABLE_MERGEJOIN;
2568         if (enable_hashjoin)
2569                 mask |= ENABLE_HASHJOIN;
2570
2571         return mask;
2572 }
2573
2574 /*
2575  * Sets GUC prameters without throwing exception. Reutrns false if something
2576  * wrong.
2577  */
2578 static int
2579 set_config_option_noerror(const char *name, const char *value,
2580                                                   GucContext context, GucSource source,
2581                                                   GucAction action, bool changeVal, int elevel)
2582 {
2583         int                             result = 0;
2584         MemoryContext   ccxt = CurrentMemoryContext;
2585
2586         PG_TRY();
2587         {
2588                 result = set_config_option(name, value, context, source,
2589                                                                    action, changeVal, 0, false);
2590         }
2591         PG_CATCH();
2592         {
2593                 ErrorData          *errdata;
2594
2595                 /* Save error info */
2596                 MemoryContextSwitchTo(ccxt);
2597                 errdata = CopyErrorData();
2598                 FlushErrorState();
2599
2600                 ereport(elevel,
2601                                 (errcode(errdata->sqlerrcode),
2602                                  errmsg("%s", errdata->message),
2603                                  errdata->detail ? errdetail("%s", errdata->detail) : 0,
2604                                  errdata->hint ? errhint("%s", errdata->hint) : 0));
2605                 msgqno = qno;
2606                 FreeErrorData(errdata);
2607         }
2608         PG_END_TRY();
2609
2610         return result;
2611 }
2612
2613 /*
2614  * Sets GUC parameter of int32 type without throwing exceptions. Returns false
2615  * if something wrong.
2616  */
2617 static int
2618 set_config_int32_option(const char *name, int32 value, GucContext context)
2619 {
2620         char buf[16];   /* enough for int32 */
2621
2622         if (snprintf(buf, 16, "%d", value) < 0)
2623         {
2624                 ereport(pg_hint_plan_parse_message_level,
2625                                 (errmsg ("Failed to convert integer to string: %d", value)));
2626                 return false;
2627         }
2628
2629         return
2630                 set_config_option_noerror(name, buf, context,
2631                                                                   PGC_S_SESSION, GUC_ACTION_SAVE, true,
2632                                                                   pg_hint_plan_parse_message_level);
2633 }
2634
2635 /*
2636  * Sets GUC parameter of double type without throwing exceptions. Returns false
2637  * if something wrong.
2638  */
2639 static int
2640 set_config_double_option(const char *name, double value, GucContext context)
2641 {
2642         char *buf = float8out_internal(value);
2643         int       result;
2644
2645         result = set_config_option_noerror(name, buf, context,
2646                                                                            PGC_S_SESSION, GUC_ACTION_SAVE, true,
2647                                                                            pg_hint_plan_parse_message_level);
2648         pfree(buf);
2649         return result;
2650 }
2651
2652 /* setup scan method enforcement according to given options */
2653 static void
2654 setup_guc_enforcement(SetHint **options, int noptions, GucContext context)
2655 {
2656         int     i;
2657
2658         for (i = 0; i < noptions; i++)
2659         {
2660                 SetHint    *hint = options[i];
2661                 int                     result;
2662
2663                 if (!hint_state_enabled(hint))
2664                         continue;
2665
2666                 result = set_config_option_noerror(hint->name, hint->value, context,
2667                                                                                    PGC_S_SESSION, GUC_ACTION_SAVE, true,
2668                                                                                    pg_hint_plan_parse_message_level);
2669                 if (result != 0)
2670                         hint->base.state = HINT_STATE_USED;
2671                 else
2672                         hint->base.state = HINT_STATE_ERROR;
2673         }
2674
2675         return;
2676 }
2677
2678 /*
2679  * Setup parallel execution environment.
2680  *
2681  * If hint is not NULL, set up using it, elsewise reset to initial environment.
2682  */
2683 static void
2684 setup_parallel_plan_enforcement(ParallelHint *hint, HintState *state)
2685 {
2686         if (hint)
2687         {
2688                 hint->base.state = HINT_STATE_USED;
2689                 set_config_int32_option("max_parallel_workers_per_gather",
2690                                                                 hint->nworkers, state->context);
2691         }
2692         else
2693                 set_config_int32_option("max_parallel_workers_per_gather",
2694                                                                 state->init_nworkers, state->context);
2695
2696         /* force means that enforce parallel as far as possible */
2697         if (hint && hint->force_parallel && hint->nworkers > 0)
2698         {
2699                 set_config_double_option("parallel_tuple_cost", 0.0, state->context);
2700                 set_config_double_option("parallel_setup_cost", 0.0, state->context);
2701                 set_config_int32_option("min_parallel_table_scan_size", 0,
2702                                                                 state->context);
2703                 set_config_int32_option("min_parallel_index_scan_size", 0,
2704                                                                 state->context);
2705         }
2706         else
2707         {
2708                 set_config_double_option("parallel_tuple_cost",
2709                                                                 state->init_paratup_cost, state->context);
2710                 set_config_double_option("parallel_setup_cost",
2711                                                                 state->init_parasetup_cost, state->context);
2712                 set_config_int32_option("min_parallel_table_scan_size",
2713                                                                 state->init_min_para_tablescan_size,
2714                                                                 state->context);
2715                 set_config_int32_option("min_parallel_index_scan_size",
2716                                                                 state->init_min_para_indexscan_size,
2717                                                                 state->context);
2718         }
2719 }
2720
2721 #define SET_CONFIG_OPTION(name, type_bits) \
2722         set_config_option_noerror((name), \
2723                 (mask & (type_bits)) ? "true" : "false", \
2724                 context, PGC_S_SESSION, GUC_ACTION_SAVE, true, ERROR)
2725
2726
2727 /*
2728  * Setup GUC environment to enforce scan methods. If scanhint is NULL, reset
2729  * GUCs to the saved state in state.
2730  */
2731 static void
2732 setup_scan_method_enforcement(ScanMethodHint *scanhint, HintState *state)
2733 {
2734         unsigned char   enforce_mask = state->init_scan_mask;
2735         GucContext              context = state->context;
2736         unsigned char   mask;
2737
2738         if (scanhint)
2739         {
2740                 enforce_mask = scanhint->enforce_mask;
2741                 scanhint->base.state = HINT_STATE_USED;
2742         }
2743
2744         if (enforce_mask == ENABLE_SEQSCAN || enforce_mask == ENABLE_INDEXSCAN ||
2745                 enforce_mask == ENABLE_BITMAPSCAN || enforce_mask == ENABLE_TIDSCAN
2746                 || enforce_mask == (ENABLE_INDEXSCAN | ENABLE_INDEXONLYSCAN)
2747                 )
2748                 mask = enforce_mask;
2749         else
2750                 mask = enforce_mask & current_hint_state->init_scan_mask;
2751
2752         SET_CONFIG_OPTION("enable_seqscan", ENABLE_SEQSCAN);
2753         SET_CONFIG_OPTION("enable_indexscan", ENABLE_INDEXSCAN);
2754         SET_CONFIG_OPTION("enable_bitmapscan", ENABLE_BITMAPSCAN);
2755         SET_CONFIG_OPTION("enable_tidscan", ENABLE_TIDSCAN);
2756         SET_CONFIG_OPTION("enable_indexonlyscan", ENABLE_INDEXONLYSCAN);
2757 }
2758
2759 static void
2760 set_join_config_options(unsigned char enforce_mask, GucContext context)
2761 {
2762         unsigned char   mask;
2763
2764         if (enforce_mask == ENABLE_NESTLOOP || enforce_mask == ENABLE_MERGEJOIN ||
2765                 enforce_mask == ENABLE_HASHJOIN)
2766                 mask = enforce_mask;
2767         else
2768                 mask = enforce_mask & current_hint_state->init_join_mask;
2769
2770         SET_CONFIG_OPTION("enable_nestloop", ENABLE_NESTLOOP);
2771         SET_CONFIG_OPTION("enable_mergejoin", ENABLE_MERGEJOIN);
2772         SET_CONFIG_OPTION("enable_hashjoin", ENABLE_HASHJOIN);
2773 }
2774
2775 /*
2776  * Push a hint into hint stack which is implemented with List struct.  Head of
2777  * list is top of stack.
2778  */
2779 static void
2780 push_hint(HintState *hstate)
2781 {
2782         /* Prepend new hint to the list means pushing to stack. */
2783         HintStateStack = lcons(hstate, HintStateStack);
2784
2785         /* Pushed hint is the one which should be used hereafter. */
2786         current_hint_state = hstate;
2787 }
2788
2789 /* Pop a hint from hint stack.  Popped hint is automatically discarded. */
2790 static void
2791 pop_hint(void)
2792 {
2793         /* Hint stack must not be empty. */
2794         if(HintStateStack == NIL)
2795                 elog(ERROR, "hint stack is empty");
2796
2797         /*
2798          * Take a hint at the head from the list, and free it.  Switch
2799          * current_hint_state to point new head (NULL if the list is empty).
2800          */
2801         HintStateStack = list_delete_first(HintStateStack);
2802         HintStateDelete(current_hint_state);
2803         if(HintStateStack == NIL)
2804                 current_hint_state = NULL;
2805         else
2806                 current_hint_state = (HintState *) lfirst(list_head(HintStateStack));
2807 }
2808
2809 /*
2810  * Retrieve and store hint string from given query or from the hint table.
2811  */
2812 static void
2813 get_current_hint_string(ParseState *pstate, Query *query)
2814 {
2815         const char *query_str;
2816         MemoryContext   oldcontext;
2817
2818         /* do nothing under hint table search */
2819         if (hint_inhibit_level > 0)
2820                 return;
2821
2822         /* We alredy have one, don't parse it again. */
2823         if (current_hint_retrieved)
2824                 return;
2825
2826         /* Don't parse the current query hereafter */
2827         current_hint_retrieved = true;
2828
2829         if (!pg_hint_plan_enable_hint)
2830         {
2831                 if (current_hint_str)
2832                 {
2833                         pfree((void *)current_hint_str);
2834                         current_hint_str = NULL;
2835                 }
2836                 return;
2837         }
2838
2839         /* increment the query number */
2840         qnostr[0] = 0;
2841         if (debug_level > 1)
2842                 snprintf(qnostr, sizeof(qnostr), "[qno=0x%x]", qno++);
2843         qno++;
2844
2845         /* search the hint table for a hint if requested */
2846         if (pg_hint_plan_enable_hint_table)
2847         {
2848                 int                             query_len;
2849                 pgssJumbleState jstate;
2850                 Query              *jumblequery;
2851                 char               *normalized_query = NULL;
2852
2853                 query_str = get_query_string(pstate, query, &jumblequery);
2854
2855                 /* If this query is not for hint, just return */
2856                 if (!query_str)
2857                         return;
2858
2859                 /* clear the previous hint string */
2860                 if (current_hint_str)
2861                 {
2862                         pfree((void *)current_hint_str);
2863                         current_hint_str = NULL;
2864                 }
2865
2866                 if (jumblequery)
2867                 {
2868                         /*
2869                          * XXX: normalization code is copied from pg_stat_statements.c.
2870                          * Make sure to keep up-to-date with it.
2871                          */
2872                         jstate.jumble = (unsigned char *) palloc(JUMBLE_SIZE);
2873                         jstate.jumble_len = 0;
2874                         jstate.clocations_buf_size = 32;
2875                         jstate.clocations = (pgssLocationLen *)
2876                                 palloc(jstate.clocations_buf_size * sizeof(pgssLocationLen));
2877                         jstate.clocations_count = 0;
2878
2879                         JumbleQuery(&jstate, jumblequery);
2880
2881                         /*
2882                          * Normalize the query string by replacing constants with '?'
2883                          */
2884                         /*
2885                          * Search hint string which is stored keyed by query string
2886                          * and application name.  The query string is normalized to allow
2887                          * fuzzy matching.
2888                          *
2889                          * Adding 1 byte to query_len ensures that the returned string has
2890                          * a terminating NULL.
2891                          */
2892                         query_len = strlen(query_str) + 1;
2893                         normalized_query =
2894                                 generate_normalized_query(&jstate, query_str, 0, &query_len,
2895                                                                                   GetDatabaseEncoding());
2896
2897                         /*
2898                          * find a hint for the normalized query. the result should be in
2899                          * TopMemoryContext
2900                          */
2901                         oldcontext = MemoryContextSwitchTo(TopMemoryContext);
2902                         current_hint_str =
2903                                 get_hints_from_table(normalized_query, application_name);
2904                         MemoryContextSwitchTo(oldcontext);
2905
2906                         if (debug_level > 1)
2907                         {
2908                                 if (current_hint_str)
2909                                         ereport(pg_hint_plan_debug_message_level,
2910                                                         (errmsg("pg_hint_plan[qno=0x%x]: "
2911                                                                         "post_parse_analyze_hook: "
2912                                                                         "hints from table: \"%s\": "
2913                                                                         "normalized_query=\"%s\", "
2914                                                                         "application name =\"%s\"",
2915                                                                         qno, current_hint_str,
2916                                                                         normalized_query, application_name),
2917                                                          errhidestmt(msgqno != qno),
2918                                                          errhidecontext(msgqno != qno)));
2919                                 else
2920                                         ereport(pg_hint_plan_debug_message_level,
2921                                                         (errmsg("pg_hint_plan[qno=0x%x]: "
2922                                                                         "no match found in table:  "
2923                                                                         "application name = \"%s\", "
2924                                                                         "normalized_query=\"%s\"",
2925                                                                         qno, application_name,
2926                                                                         normalized_query),
2927                                                          errhidestmt(msgqno != qno),
2928                                                          errhidecontext(msgqno != qno)));
2929
2930                                 msgqno = qno;
2931                         }
2932                 }
2933
2934                 /* retrun if we have hint here */
2935                 if (current_hint_str)
2936                         return;
2937         }
2938         else
2939                 query_str = get_query_string(pstate, query, NULL);
2940
2941         if (query_str)
2942         {
2943                 /*
2944                  * get hints from the comment. However we may have the same query
2945                  * string with the previous call, but the extra comparison seems no
2946                  * use..
2947                  */
2948                 if (current_hint_str)
2949                         pfree((void *)current_hint_str);
2950
2951                 oldcontext = MemoryContextSwitchTo(TopMemoryContext);
2952                 current_hint_str = get_hints_from_comment(query_str);
2953                 MemoryContextSwitchTo(oldcontext);
2954         }
2955         else
2956         {
2957                 /*
2958                  * Failed to get query. We would be in fetching invalidated
2959                  * plancache. Try the next chance.
2960                  */
2961                 current_hint_retrieved = false;
2962         }
2963
2964         if (debug_level > 1)
2965         {
2966                 if (debug_level == 1 && query_str && debug_query_string &&
2967                         strcmp(query_str, debug_query_string))
2968                         ereport(pg_hint_plan_debug_message_level,
2969                                         (errmsg("hints in comment=\"%s\"",
2970                                                         current_hint_str ? current_hint_str : "(none)"),
2971                                          errhidestmt(msgqno != qno),
2972                                          errhidecontext(msgqno != qno)));
2973                 else
2974                         ereport(pg_hint_plan_debug_message_level,
2975                                         (errmsg("hints in comment=\"%s\", query=\"%s\", debug_query_string=\"%s\"",
2976                                                         current_hint_str ? current_hint_str : "(none)",
2977                                                         query_str ? query_str : "(none)",
2978                                                         debug_query_string ? debug_query_string : "(none)"),
2979                                          errhidestmt(msgqno != qno),
2980                                          errhidecontext(msgqno != qno)));
2981                 msgqno = qno;
2982         }
2983 }
2984
2985 /*
2986  * Retrieve hint string from the current query.
2987  */
2988 static void
2989 pg_hint_plan_post_parse_analyze(ParseState *pstate, Query *query)
2990 {
2991         if (prev_post_parse_analyze_hook)
2992                 prev_post_parse_analyze_hook(pstate, query);
2993
2994         /* always retrieve hint from the top-level query string */
2995         if (plpgsql_recurse_level == 0)
2996                 current_hint_retrieved = false;
2997
2998         get_current_hint_string(pstate, query);
2999 }
3000
3001 /*
3002  * We need to reset current_hint_retrieved flag always when a command execution
3003  * is finished. This is true even for a pure utility command that doesn't
3004  * involve planning phase.
3005  */
3006 static void
3007 pg_hint_plan_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
3008                                         ProcessUtilityContext context,
3009                                         ParamListInfo params, QueryEnvironment *queryEnv,
3010                                         DestReceiver *dest, char *completionTag)
3011 {
3012         if (prev_ProcessUtility_hook)
3013                 prev_ProcessUtility_hook(pstmt, queryString, context, params, queryEnv,
3014                                                                  dest, completionTag);
3015         else
3016                 standard_ProcessUtility(pstmt, queryString, context, params, queryEnv,
3017                                                                  dest, completionTag);
3018
3019         if (plpgsql_recurse_level == 0)
3020                 current_hint_retrieved = false;
3021 }
3022
3023 /*
3024  * Read and set up hint information
3025  */
3026 static PlannedStmt *
3027 pg_hint_plan_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
3028 {
3029         int                             save_nestlevel;
3030         PlannedStmt        *result;
3031         HintState          *hstate;
3032         const char         *prev_hint_str = NULL;
3033
3034         /*
3035          * Use standard planner if pg_hint_plan is disabled or current nesting
3036          * depth is nesting depth of SPI calls. Other hook functions try to change
3037          * plan with current_hint_state if any, so set it to NULL.
3038          */
3039         if (!pg_hint_plan_enable_hint || hint_inhibit_level > 0)
3040         {
3041                 if (debug_level > 1)
3042                         ereport(pg_hint_plan_debug_message_level,
3043                                         (errmsg ("pg_hint_plan%s: planner: enable_hint=%d,"
3044                                                          " hint_inhibit_level=%d",
3045                                                          qnostr, pg_hint_plan_enable_hint,
3046                                                          hint_inhibit_level),
3047                                          errhidestmt(msgqno != qno)));
3048                 msgqno = qno;
3049
3050                 goto standard_planner_proc;
3051         }
3052
3053         /*
3054          * Support for nested plpgsql functions. This is quite ugly but this is the
3055          * only point I could find where I can get the query string.
3056          */
3057         if (plpgsql_recurse_level > 0 &&
3058                 error_context_stack && error_context_stack->arg)
3059         {
3060                 MemoryContext oldcontext;
3061
3062                 oldcontext = MemoryContextSwitchTo(TopMemoryContext);
3063                 current_hint_str =
3064                         get_hints_from_comment((char *)error_context_stack->arg);
3065                 MemoryContextSwitchTo(oldcontext);
3066         }
3067
3068         /*
3069          * Query execution in extended protocol can be started without the analyze
3070          * phase. In the case retrieve hint string here.
3071          */
3072         if (!current_hint_str)
3073                 get_current_hint_string(NULL, parse);
3074
3075         /* No hint, go the normal way */
3076         if (!current_hint_str)
3077                 goto standard_planner_proc;
3078
3079         /* parse the hint into hint state struct */
3080         hstate = create_hintstate(parse, pstrdup(current_hint_str));
3081
3082         /* run standard planner if the statement has not valid hint */
3083         if (!hstate)
3084                 goto standard_planner_proc;
3085
3086         /*
3087          * Push new hint struct to the hint stack to disable previous hint context.
3088          */
3089         push_hint(hstate);
3090
3091         /*  Set scan enforcement here. */
3092         save_nestlevel = NewGUCNestLevel();
3093
3094         /* Apply Set hints, then save it as the initial state  */
3095         setup_guc_enforcement(current_hint_state->set_hints,
3096                                                    current_hint_state->num_hints[HINT_TYPE_SET],
3097                                                    current_hint_state->context);
3098
3099         current_hint_state->init_scan_mask = get_current_scan_mask();
3100         current_hint_state->init_join_mask = get_current_join_mask();
3101         current_hint_state->init_min_para_tablescan_size =
3102                 min_parallel_table_scan_size;
3103         current_hint_state->init_min_para_indexscan_size =
3104                 min_parallel_index_scan_size;
3105         current_hint_state->init_paratup_cost = parallel_tuple_cost;
3106         current_hint_state->init_parasetup_cost = parallel_setup_cost;
3107
3108         /*
3109          * max_parallel_workers_per_gather should be non-zero here if Workers hint
3110          * is specified.
3111          */
3112         if (max_hint_nworkers > 0 && max_parallel_workers_per_gather < 1)
3113                 set_config_int32_option("max_parallel_workers_per_gather",
3114                                                                 1, current_hint_state->context);
3115         current_hint_state->init_nworkers = max_parallel_workers_per_gather;
3116
3117         if (debug_level > 1)
3118         {
3119                 ereport(pg_hint_plan_debug_message_level,
3120                                 (errhidestmt(msgqno != qno),
3121                                  errmsg("pg_hint_plan%s: planner", qnostr)));
3122                 msgqno = qno;
3123         }
3124
3125         /*
3126          * The planner call below may replace current_hint_str. Store and restore
3127          * it so that the subsequent planning in the upper level doesn't get
3128          * confused.
3129          */
3130         recurse_level++;
3131         prev_hint_str = current_hint_str;
3132         current_hint_str = NULL;
3133
3134         /*
3135          * Use PG_TRY mechanism to recover GUC parameters and current_hint_state to
3136          * the state when this planner started when error occurred in planner.
3137          */
3138         PG_TRY();
3139         {
3140                 if (prev_planner)
3141                         result = (*prev_planner) (parse, cursorOptions, boundParams);
3142                 else
3143                         result = standard_planner(parse, cursorOptions, boundParams);
3144
3145                 current_hint_str = prev_hint_str;
3146                 recurse_level--;
3147         }
3148         PG_CATCH();
3149         {
3150                 /*
3151                  * Rollback changes of GUC parameters, and pop current hint context
3152                  * from hint stack to rewind the state.
3153                  */
3154                 current_hint_str = prev_hint_str;
3155                 recurse_level--;
3156                 AtEOXact_GUC(true, save_nestlevel);
3157                 pop_hint();
3158                 PG_RE_THROW();
3159         }
3160         PG_END_TRY();
3161
3162
3163         /*
3164          * current_hint_str is useless after planning of the top-level query.
3165          */
3166         if (recurse_level < 1 && current_hint_str)
3167         {
3168                 pfree((void *)current_hint_str);
3169                 current_hint_str = NULL;
3170                 current_hint_retrieved = false;
3171         }
3172
3173         /* Print hint in debug mode. */
3174         if (debug_level == 1)
3175                 HintStateDump(current_hint_state);
3176         else if (debug_level > 1)
3177                 HintStateDump2(current_hint_state);
3178
3179         /*
3180          * Rollback changes of GUC parameters, and pop current hint context from
3181          * hint stack to rewind the state.
3182          */
3183         AtEOXact_GUC(true, save_nestlevel);
3184         pop_hint();
3185
3186         return result;
3187
3188 standard_planner_proc:
3189         if (debug_level > 1)
3190         {
3191                 ereport(pg_hint_plan_debug_message_level,
3192                                 (errhidestmt(msgqno != qno),
3193                                  errmsg("pg_hint_plan%s: planner: no valid hint",
3194                                                 qnostr)));
3195                 msgqno = qno;
3196         }
3197         current_hint_state = NULL;
3198         if (prev_planner)
3199                 result =  (*prev_planner) (parse, cursorOptions, boundParams);
3200         else
3201                 result = standard_planner(parse, cursorOptions, boundParams);
3202
3203         /* The upper-level planner still needs the current hint state */
3204         if (HintStateStack != NIL)
3205                 current_hint_state = (HintState *) lfirst(list_head(HintStateStack));
3206
3207         return result;
3208 }
3209
3210 /*
3211  * Find scan method hint to be applied to the given relation
3212  *
3213  */
3214 static ScanMethodHint *
3215 find_scan_hint(PlannerInfo *root, Index relid)
3216 {
3217         RelOptInfo         *rel;
3218         RangeTblEntry  *rte;
3219         ScanMethodHint  *real_name_hint = NULL;
3220         ScanMethodHint  *alias_hint = NULL;
3221         int                             i;
3222
3223         /* This should not be a join rel */
3224         Assert(relid > 0);
3225         rel = root->simple_rel_array[relid];
3226
3227         /*
3228          * This function is called for any RelOptInfo or its inheritance parent if
3229          * any. If we are called from inheritance planner, the RelOptInfo for the
3230          * parent of target child relation is not set in the planner info.
3231          *
3232          * Otherwise we should check that the reloptinfo is base relation or
3233          * inheritance children.
3234          */
3235         if (rel &&
3236                 rel->reloptkind != RELOPT_BASEREL &&
3237                 rel->reloptkind != RELOPT_OTHER_MEMBER_REL)
3238                 return NULL;
3239
3240         /*
3241          * This is baserel or appendrel children. We can refer to RangeTblEntry.
3242          */
3243         rte = root->simple_rte_array[relid];
3244         Assert(rte);
3245
3246         /* We don't hint on other than relation and foreign tables */
3247         if (rte->rtekind != RTE_RELATION ||
3248                 rte->relkind == RELKIND_FOREIGN_TABLE)
3249                 return NULL;
3250
3251         /* Find scan method hint, which matches given names, from the list. */
3252         for (i = 0; i < current_hint_state->num_hints[HINT_TYPE_SCAN_METHOD]; i++)
3253         {
3254                 ScanMethodHint *hint = current_hint_state->scan_hints[i];
3255
3256                 /* We ignore disabled hints. */
3257                 if (!hint_state_enabled(hint))
3258                         continue;
3259
3260                 if (!alias_hint &&
3261                         RelnameCmp(&rte->eref->aliasname, &hint->relname) == 0)
3262                         alias_hint = hint;
3263
3264                 /* check the real name for appendrel children */
3265                 if (!real_name_hint &&
3266                         rel && rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
3267                 {
3268                         char *realname = get_rel_name(rte->relid);
3269
3270                         if (realname && RelnameCmp(&realname, &hint->relname) == 0)
3271                                 real_name_hint = hint;
3272                 }
3273
3274                 /* No more match expected, break  */
3275                 if(alias_hint && real_name_hint)
3276                         break;
3277         }
3278
3279         /* real name match precedes alias match */
3280         if (real_name_hint)
3281                 return real_name_hint;
3282
3283         return alias_hint;
3284 }
3285
3286 static ParallelHint *
3287 find_parallel_hint(PlannerInfo *root, Index relid)
3288 {
3289         RelOptInfo         *rel;
3290         RangeTblEntry  *rte;
3291         ParallelHint    *real_name_hint = NULL;
3292         ParallelHint    *alias_hint = NULL;
3293         int                             i;
3294
3295         /* This should not be a join rel */
3296         Assert(relid > 0);
3297         rel = root->simple_rel_array[relid];
3298
3299         /*
3300          * Parallel planning is appliable only on base relation, which has
3301          * RelOptInfo.
3302          */
3303         if (!rel)
3304                 return NULL;
3305
3306         /*
3307          * We have set root->glob->parallelModeOK if needed. What we should do here
3308          * is just following the decision of planner.
3309          */
3310         if (!rel->consider_parallel)
3311                 return NULL;
3312
3313         /*
3314          * This is baserel or appendrel children. We can refer to RangeTblEntry.
3315          */
3316         rte = root->simple_rte_array[relid];
3317         Assert(rte);
3318
3319         /* Find parallel method hint, which matches given names, from the list. */
3320         for (i = 0; i < current_hint_state->num_hints[HINT_TYPE_PARALLEL]; i++)
3321         {
3322                 ParallelHint *hint = current_hint_state->parallel_hints[i];
3323
3324                 /* We ignore disabled hints. */
3325                 if (!hint_state_enabled(hint))
3326                         continue;
3327
3328                 if (!alias_hint &&
3329                         RelnameCmp(&rte->eref->aliasname, &hint->relname) == 0)
3330                         alias_hint = hint;
3331
3332                 /* check the real name for appendrel children */
3333                 if (!real_name_hint &&
3334                         rel && rel->reloptkind == RELOPT_OTHER_MEMBER_REL)
3335                 {
3336                         char *realname = get_rel_name(rte->relid);
3337
3338                         if (realname && RelnameCmp(&realname, &hint->relname) == 0)
3339                                 real_name_hint = hint;
3340                 }
3341
3342                 /* No more match expected, break  */
3343                 if(alias_hint && real_name_hint)
3344                         break;
3345         }
3346
3347         /* real name match precedes alias match */
3348         if (real_name_hint)
3349                 return real_name_hint;
3350
3351         return alias_hint;
3352 }
3353
3354 /*
3355  * regexeq
3356  *
3357  * Returns TRUE on match, FALSE on no match.
3358  *
3359  *   s1 --- the data to match against
3360  *   s2 --- the pattern
3361  *
3362  * Because we copy s1 to NameData, make the size of s1 less than NAMEDATALEN.
3363  */
3364 static bool
3365 regexpeq(const char *s1, const char *s2)
3366 {
3367         NameData        name;
3368         text       *regexp;
3369         Datum           result;
3370
3371         strcpy(name.data, s1);
3372         regexp = cstring_to_text(s2);
3373
3374         result = DirectFunctionCall2Coll(nameregexeq,
3375                                                                          DEFAULT_COLLATION_OID,
3376                                                                          NameGetDatum(&name),
3377                                                                          PointerGetDatum(regexp));
3378         return DatumGetBool(result);
3379 }
3380
3381
3382 /* Remove indexes instructed not to use by hint. */
3383 static void
3384 restrict_indexes(PlannerInfo *root, ScanMethodHint *hint, RelOptInfo *rel,
3385                            bool using_parent_hint)
3386 {
3387         ListCell           *cell;
3388         ListCell           *prev;
3389         ListCell           *next;
3390         StringInfoData  buf;
3391         RangeTblEntry  *rte = root->simple_rte_array[rel->relid];
3392         Oid                             relationObjectId = rte->relid;
3393
3394         /*
3395          * We delete all the IndexOptInfo list and prevent you from being usable by
3396          * a scan.
3397          */
3398         if (hint->enforce_mask == ENABLE_SEQSCAN ||
3399                 hint->enforce_mask == ENABLE_TIDSCAN)
3400         {
3401                 list_free_deep(rel->indexlist);
3402                 rel->indexlist = NIL;
3403                 hint->base.state = HINT_STATE_USED;
3404
3405                 return;
3406         }
3407
3408         /*
3409          * When a list of indexes is not specified, we just use all indexes.
3410          */
3411         if (hint->indexnames == NIL)
3412                 return;
3413
3414         /*
3415          * Leaving only an specified index, we delete it from a IndexOptInfo list
3416          * other than it.
3417          */
3418         prev = NULL;
3419         if (debug_level > 0)
3420                 initStringInfo(&buf);
3421
3422         for (cell = list_head(rel->indexlist); cell; cell = next)
3423         {
3424                 IndexOptInfo   *info = (IndexOptInfo *) lfirst(cell);
3425                 char               *indexname = get_rel_name(info->indexoid);
3426                 ListCell           *l;
3427                 bool                    use_index = false;
3428
3429                 next = lnext(cell);
3430
3431                 foreach(l, hint->indexnames)
3432                 {
3433                         char   *hintname = (char *) lfirst(l);
3434                         bool    result;
3435
3436                         if (hint->regexp)
3437                                 result = regexpeq(indexname, hintname);
3438                         else
3439                                 result = RelnameCmp(&indexname, &hintname) == 0;
3440
3441                         if (result)
3442                         {
3443                                 use_index = true;
3444                                 if (debug_level > 0)
3445                                 {
3446                                         appendStringInfoCharMacro(&buf, ' ');
3447                                         quote_value(&buf, indexname);
3448                                 }
3449
3450                                 break;
3451                         }
3452                 }
3453
3454                 /*
3455                  * Apply index restriction of parent hint to children. Since index
3456                  * inheritance is not explicitly described we should search for an
3457                  * children's index with the same definition to that of the parent.
3458                  */
3459                 if (using_parent_hint && !use_index)
3460                 {
3461                         foreach(l, current_hint_state->parent_index_infos)
3462                         {
3463                                 int                                     i;
3464                                 HeapTuple                       ht_idx;
3465                                 ParentIndexInfo    *p_info = (ParentIndexInfo *)lfirst(l);
3466
3467                                 /*
3468                                  * we check the 'same' index by comparing uniqueness, access
3469                                  * method and index key columns.
3470                                  */
3471                                 if (p_info->indisunique != info->unique ||
3472                                         p_info->method != info->relam ||
3473                                         list_length(p_info->column_names) != info->ncolumns)
3474                                         continue;
3475
3476                                 /* Check if index key columns match */
3477                                 for (i = 0; i < info->ncolumns; i++)
3478                                 {
3479                                         char       *c_attname = NULL;
3480                                         char       *p_attname = NULL;
3481
3482                                         p_attname = list_nth(p_info->column_names, i);
3483
3484                                         /*
3485                                          * if both of the key of the same position are expressions,
3486                                          * ignore them for now and check later.
3487                                          */
3488                                         if (info->indexkeys[i] == 0 && !p_attname)
3489                                                 continue;
3490
3491                                         /* deny if one is expression while another is not */
3492                                         if (info->indexkeys[i] == 0 || !p_attname)
3493                                                 break;
3494
3495                                         c_attname = get_attname(relationObjectId,
3496                                                                                         info->indexkeys[i], false);
3497
3498                                         /* deny if any of column attributes don't match */
3499                                         if (strcmp(p_attname, c_attname) != 0 ||
3500                                                 p_info->indcollation[i] != info->indexcollations[i] ||
3501                                                 p_info->opclass[i] != info->opcintype[i]||
3502                                                 ((p_info->indoption[i] & INDOPTION_DESC) != 0)
3503                                                 != info->reverse_sort[i] ||
3504                                                 ((p_info->indoption[i] & INDOPTION_NULLS_FIRST) != 0)
3505                                                 != info->nulls_first[i])
3506                                                 break;
3507                                 }
3508
3509                                 /* deny this if any difference found */
3510                                 if (i != info->ncolumns)
3511                                         continue;
3512
3513                                 /* check on key expressions  */
3514                                 if ((p_info->expression_str && (info->indexprs != NIL)) ||
3515                                         (p_info->indpred_str && (info->indpred != NIL)))
3516                                 {
3517                                         /* fetch the index of this child */
3518                                         ht_idx = SearchSysCache1(INDEXRELID,
3519                                                                                          ObjectIdGetDatum(info->indexoid));
3520
3521                                         /* check expressions if both expressions are available */
3522                                         if (p_info->expression_str &&
3523                                                 !heap_attisnull(ht_idx, Anum_pg_index_indexprs, NULL))
3524                                         {
3525                                                 Datum       exprsDatum;
3526                                                 bool        isnull;
3527                                                 Datum       result;
3528
3529                                                 /*
3530                                                  * to change the expression's parameter of child's
3531                                                  * index to strings
3532                                                  */
3533                                                 exprsDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
3534                                                                                                          Anum_pg_index_indexprs,
3535                                                                                                          &isnull);
3536
3537                                                 result = DirectFunctionCall2(pg_get_expr,
3538                                                                                                          exprsDatum,
3539                                                                                                          ObjectIdGetDatum(
3540                                                                                                                  relationObjectId));
3541
3542                                                 /* deny if expressions don't match */
3543                                                 if (strcmp(p_info->expression_str,
3544                                                                    text_to_cstring(DatumGetTextP(result))) != 0)
3545                                                 {
3546                                                         /* Clean up */
3547                                                         ReleaseSysCache(ht_idx);
3548                                                         continue;
3549                                                 }
3550                                         }
3551
3552                                         /* compare index predicates  */
3553                                         if (p_info->indpred_str &&
3554                                                 !heap_attisnull(ht_idx, Anum_pg_index_indpred, NULL))
3555                                         {
3556                                                 Datum       predDatum;
3557                                                 bool        isnull;
3558                                                 Datum       result;
3559
3560                                                 predDatum = SysCacheGetAttr(INDEXRELID, ht_idx,
3561                                                                                                          Anum_pg_index_indpred,
3562                                                                                                          &isnull);
3563
3564                                                 result = DirectFunctionCall2(pg_get_expr,
3565                                                                                                          predDatum,
3566                                                                                                          ObjectIdGetDatum(
3567                                                                                                                  relationObjectId));
3568
3569                                                 if (strcmp(p_info->indpred_str,
3570                                                                    text_to_cstring(DatumGetTextP(result))) != 0)
3571                                                 {
3572                                                         /* Clean up */
3573                                                         ReleaseSysCache(ht_idx);
3574                                                         continue;
3575                                                 }
3576                                         }
3577
3578                                         /* Clean up */
3579                                         ReleaseSysCache(ht_idx);
3580                                 }
3581                                 else if (p_info->expression_str || (info->indexprs != NIL))
3582                                         continue;
3583                                 else if (p_info->indpred_str || (info->indpred != NIL))
3584                                         continue;
3585
3586                                 use_index = true;
3587
3588                                 /* to log the candidate of index */
3589                                 if (debug_level > 0)
3590                                 {
3591                                         appendStringInfoCharMacro(&buf, ' ');
3592                                         quote_value(&buf, indexname);
3593                                 }
3594
3595                                 break;
3596                         }
3597                 }
3598
3599                 if (!use_index)
3600                         rel->indexlist = list_delete_cell(rel->indexlist, cell, prev);
3601                 else
3602                         prev = cell;
3603
3604                 pfree(indexname);
3605         }
3606
3607         if (debug_level == 1)
3608         {
3609                 StringInfoData  rel_buf;
3610                 char *disprelname = "";
3611
3612                 /*
3613                  * If this hint targetted the parent, use the real name of this
3614                  * child. Otherwise use hint specification.
3615                  */
3616                 if (using_parent_hint)
3617                         disprelname = get_rel_name(rte->relid);
3618                 else
3619                         disprelname = hint->relname;
3620
3621
3622                 initStringInfo(&rel_buf);
3623                 quote_value(&rel_buf, disprelname);
3624
3625                 ereport(pg_hint_plan_debug_message_level,
3626                                 (errmsg("available indexes for %s(%s):%s",
3627                                          hint->base.keyword,
3628                                          rel_buf.data,
3629                                          buf.data)));
3630                 pfree(buf.data);
3631                 pfree(rel_buf.data);
3632         }
3633 }
3634
3635 /*
3636  * Return information of index definition.
3637  */
3638 static ParentIndexInfo *
3639 get_parent_index_info(Oid indexoid, Oid relid)
3640 {
3641         ParentIndexInfo *p_info = palloc(sizeof(ParentIndexInfo));
3642         Relation            indexRelation;
3643         Form_pg_index   index;
3644         char               *attname;
3645         int                             i;
3646
3647         indexRelation = index_open(indexoid, RowExclusiveLock);
3648
3649         index = indexRelation->rd_index;
3650
3651         p_info->indisunique = index->indisunique;
3652         p_info->method = indexRelation->rd_rel->relam;
3653
3654         p_info->column_names = NIL;
3655         p_info->indcollation = (Oid *) palloc(sizeof(Oid) * index->indnatts);
3656         p_info->opclass = (Oid *) palloc(sizeof(Oid) * index->indnatts);
3657         p_info->indoption = (int16 *) palloc(sizeof(Oid) * index->indnatts);
3658
3659         /*
3660          * Collect relation attribute names of index columns for index
3661          * identification, not index attribute names. NULL means expression index
3662          * columns.
3663          */
3664         for (i = 0; i < index->indnatts; i++)
3665         {
3666                 attname = get_attname(relid, index->indkey.values[i], true);
3667                 p_info->column_names = lappend(p_info->column_names, attname);
3668
3669                 p_info->indcollation[i] = indexRelation->rd_indcollation[i];
3670                 p_info->opclass[i] = indexRelation->rd_opcintype[i];
3671                 p_info->indoption[i] = indexRelation->rd_indoption[i];
3672         }
3673
3674         /*
3675          * to check to match the expression's parameter of index with child indexes
3676          */
3677         p_info->expression_str = NULL;
3678         if(!heap_attisnull(indexRelation->rd_indextuple, Anum_pg_index_indexprs,
3679                                            NULL))
3680         {
3681                 Datum       exprsDatum;
3682                 bool            isnull;
3683                 Datum           result;
3684
3685                 exprsDatum = SysCacheGetAttr(INDEXRELID, indexRelation->rd_indextuple,
3686                                                                          Anum_pg_index_indexprs, &isnull);
3687
3688                 result = DirectFunctionCall2(pg_get_expr,
3689                                                                          exprsDatum,
3690                                                                          ObjectIdGetDatum(relid));
3691
3692                 p_info->expression_str = text_to_cstring(DatumGetTextP(result));
3693         }
3694
3695         /*
3696          * to check to match the predicate's parameter of index with child indexes
3697          */
3698         p_info->indpred_str = NULL;
3699         if(!heap_attisnull(indexRelation->rd_indextuple, Anum_pg_index_indpred,
3700                                            NULL))
3701         {
3702                 Datum       predDatum;
3703                 bool            isnull;
3704                 Datum           result;
3705
3706                 predDatum = SysCacheGetAttr(INDEXRELID, indexRelation->rd_indextuple,
3707                                                                          Anum_pg_index_indpred, &isnull);
3708
3709                 result = DirectFunctionCall2(pg_get_expr,
3710                                                                          predDatum,
3711                                                                          ObjectIdGetDatum(relid));
3712
3713                 p_info->indpred_str = text_to_cstring(DatumGetTextP(result));
3714         }
3715
3716         index_close(indexRelation, NoLock);
3717
3718         return p_info;
3719 }
3720
3721 /*
3722  * cancel hint enforcement
3723  */
3724 static void
3725 reset_hint_enforcement()
3726 {
3727         setup_scan_method_enforcement(NULL, current_hint_state);
3728         setup_parallel_plan_enforcement(NULL, current_hint_state);
3729 }
3730
3731 /*
3732  * Set planner guc parameters according to corresponding scan hints.  Returns
3733  * bitmap of HintTypeBitmap. If shint or phint is not NULL, set used hint
3734  * there respectively.
3735  */
3736 static int
3737 setup_hint_enforcement(PlannerInfo *root, RelOptInfo *rel,
3738                                            ScanMethodHint **rshint, ParallelHint **rphint)
3739 {
3740         Index   new_parent_relid = 0;
3741         ListCell *l;
3742         ScanMethodHint *shint = NULL;
3743         ParallelHint   *phint = NULL;
3744         bool                    inhparent = root->simple_rte_array[rel->relid]->inh;
3745         Oid             relationObjectId = root->simple_rte_array[rel->relid]->relid;
3746         int                             ret = 0;
3747
3748         /* reset returns if requested  */
3749         if (rshint != NULL) *rshint = NULL;
3750         if (rphint != NULL) *rphint = NULL;
3751
3752         /*
3753          * We could register the parent relation of the following children here
3754          * when inhparent == true but inheritnce planner doesn't call this function
3755          * for parents. Since we cannot distinguish who called this function we
3756          * cannot do other than always seeking the parent regardless of who called
3757          * this function.
3758          */
3759         if (inhparent)
3760         {
3761                 /* set up only parallel hints for parent relation */
3762                 phint = find_parallel_hint(root, rel->relid);
3763                 if (phint)
3764                 {
3765                         setup_parallel_plan_enforcement(phint, current_hint_state);
3766                         if (rphint) *rphint = phint;
3767                         ret |= HINT_BM_PARALLEL;
3768                         return ret;
3769                 }
3770
3771                 if (debug_level > 1)
3772                         ereport(pg_hint_plan_debug_message_level,
3773                                         (errhidestmt(true),
3774                                          errmsg ("pg_hint_plan%s: setup_hint_enforcement"
3775                                                          " skipping inh parent: relation=%u(%s), inhparent=%d,"
3776                                                          " current_hint_state=%p, hint_inhibit_level=%d",
3777                                                          qnostr, relationObjectId,
3778                                                          get_rel_name(relationObjectId),
3779                                                          inhparent, current_hint_state, hint_inhibit_level)));
3780                 return 0;
3781         }
3782
3783         /* Forget about the parent of another subquery */
3784         if (root != current_hint_state->current_root)
3785                 current_hint_state->parent_relid = 0;
3786
3787         /* Find the parent for this relation other than the registered parent */
3788         foreach (l, root->append_rel_list)
3789         {
3790                 AppendRelInfo *appinfo = (AppendRelInfo *) lfirst(l);
3791
3792                 if (appinfo->child_relid == rel->relid)
3793                 {
3794                         if (current_hint_state->parent_relid != appinfo->parent_relid)
3795                         {
3796                                 new_parent_relid = appinfo->parent_relid;
3797                                 current_hint_state->current_root = root;
3798                         }
3799                         break;
3800                 }
3801         }
3802
3803         if (!l)
3804         {
3805                 /* This relation doesn't have a parent. Cancel current_hint_state. */
3806                 current_hint_state->parent_relid = 0;
3807                 current_hint_state->parent_scan_hint = NULL;
3808                 current_hint_state->parent_parallel_hint = NULL;
3809         }
3810
3811         if (new_parent_relid > 0)
3812         {
3813                 /*
3814                  * Here we found a new parent for the current relation. Scan continues
3815                  * hint to other childrens of this parent so remember it to avoid
3816                  * redundant setup cost.
3817                  */
3818                 current_hint_state->parent_relid = new_parent_relid;
3819
3820                 /* Find hints for the parent */
3821                 current_hint_state->parent_scan_hint =
3822                         find_scan_hint(root, current_hint_state->parent_relid);
3823
3824                 current_hint_state->parent_parallel_hint =
3825                         find_parallel_hint(root, current_hint_state->parent_relid);
3826
3827                 /*
3828                  * If hint is found for the parent, apply it for this child instead
3829                  * of its own.
3830                  */
3831                 if (current_hint_state->parent_scan_hint)
3832                 {
3833                         ScanMethodHint * pshint = current_hint_state->parent_scan_hint;
3834
3835                         pshint->base.state = HINT_STATE_USED;
3836
3837                         /* Apply index mask in the same manner to the parent. */
3838                         if (pshint->indexnames)
3839                         {
3840                                 Oid                     parentrel_oid;
3841                                 Relation        parent_rel;
3842
3843                                 parentrel_oid =
3844                                         root->simple_rte_array[current_hint_state->parent_relid]->relid;
3845                                 parent_rel = heap_open(parentrel_oid, NoLock);
3846
3847                                 /* Search the parent relation for indexes match the hint spec */
3848                                 foreach(l, RelationGetIndexList(parent_rel))
3849                                 {
3850                                         Oid         indexoid = lfirst_oid(l);
3851                                         char       *indexname = get_rel_name(indexoid);
3852                                         ListCell   *lc;
3853                                         ParentIndexInfo *parent_index_info;
3854
3855                                         foreach(lc, pshint->indexnames)
3856                                         {
3857                                                 if (RelnameCmp(&indexname, &lfirst(lc)) == 0)
3858                                                         break;
3859                                         }
3860                                         if (!lc)
3861                                                 continue;
3862
3863                                         parent_index_info =
3864                                                 get_parent_index_info(indexoid, parentrel_oid);
3865                                         current_hint_state->parent_index_infos =
3866                                                 lappend(current_hint_state->parent_index_infos,
3867                                                                 parent_index_info);
3868                                 }
3869                                 heap_close(parent_rel, NoLock);
3870                         }
3871                 }
3872         }
3873
3874         shint = find_scan_hint(root, rel->relid);
3875         if (!shint)
3876                 shint = current_hint_state->parent_scan_hint;
3877
3878         if (shint)
3879         {
3880                 bool using_parent_hint =
3881                         (shint == current_hint_state->parent_scan_hint);
3882
3883                 ret |= HINT_BM_SCAN_METHOD;
3884
3885                 /* Setup scan enforcement environment */
3886                 setup_scan_method_enforcement(shint, current_hint_state);
3887
3888                 /* restrict unwanted inexes */
3889                 restrict_indexes(root, shint, rel, using_parent_hint);
3890
3891                 if (debug_level > 1)
3892                 {
3893                         char *additional_message = "";
3894
3895                         if (shint == current_hint_state->parent_scan_hint)
3896                                 additional_message = " by parent hint";
3897
3898                         ereport(pg_hint_plan_debug_message_level,
3899                                         (errhidestmt(true),
3900                                          errmsg ("pg_hint_plan%s: setup_hint_enforcement"
3901                                                          " index deletion%s:"
3902                                                          " relation=%u(%s), inhparent=%d, "
3903                                                          "current_hint_state=%p,"
3904                                                          " hint_inhibit_level=%d, scanmask=0x%x",
3905                                                          qnostr, additional_message,
3906                                                          relationObjectId,
3907                                                          get_rel_name(relationObjectId),
3908                                                          inhparent, current_hint_state,
3909                                                          hint_inhibit_level,
3910                                                          shint->enforce_mask)));
3911                 }
3912         }
3913
3914         /* Do the same for parallel plan enforcement */
3915         phint = find_parallel_hint(root, rel->relid);
3916         if (!phint)
3917                 phint = current_hint_state->parent_parallel_hint;
3918
3919         setup_parallel_plan_enforcement(phint, current_hint_state);
3920
3921         if (phint)
3922                 ret |= HINT_BM_PARALLEL;
3923
3924         /* Nothing to apply. Reset the scan mask to intial state */
3925         if (!shint && ! phint)
3926         {
3927                 if (debug_level > 1)
3928                         ereport(pg_hint_plan_debug_message_level,
3929                                         (errhidestmt (true),
3930                                          errmsg ("pg_hint_plan%s: setup_hint_enforcement"
3931                                                          " no hint applied:"
3932                                                          " relation=%u(%s), inhparent=%d, current_hint=%p,"
3933                                                          " hint_inhibit_level=%d, scanmask=0x%x",
3934                                                          qnostr, relationObjectId,
3935                                                          get_rel_name(relationObjectId),
3936                                                          inhparent, current_hint_state, hint_inhibit_level,
3937                                                          current_hint_state->init_scan_mask)));
3938
3939                 setup_scan_method_enforcement(NULL,     current_hint_state);
3940
3941                 return ret;
3942         }
3943
3944         if (rshint != NULL) *rshint = shint;
3945         if (rphint != NULL) *rphint = phint;
3946
3947         return ret;
3948 }
3949
3950 /*
3951  * Return index of relation which matches given aliasname, or 0 if not found.
3952  * If same aliasname was used multiple times in a query, return -1.
3953  */
3954 static int
3955 find_relid_aliasname(PlannerInfo *root, char *aliasname, List *initial_rels,
3956                                          const char *str)
3957 {
3958         int             i;
3959         Index   found = 0;
3960
3961         for (i = 1; i < root->simple_rel_array_size; i++)
3962         {
3963                 ListCell   *l;
3964
3965                 if (root->simple_rel_array[i] == NULL)
3966                         continue;
3967
3968                 Assert(i == root->simple_rel_array[i]->relid);
3969
3970                 if (RelnameCmp(&aliasname,
3971                                            &root->simple_rte_array[i]->eref->aliasname) != 0)
3972                         continue;
3973
3974                 foreach(l, initial_rels)
3975                 {
3976                         RelOptInfo *rel = (RelOptInfo *) lfirst(l);
3977
3978                         if (rel->reloptkind == RELOPT_BASEREL)
3979                         {
3980                                 if (rel->relid != i)
3981                                         continue;
3982                         }
3983                         else
3984                         {
3985                                 Assert(rel->reloptkind == RELOPT_JOINREL);
3986
3987                                 if (!bms_is_member(i, rel->relids))
3988                                         continue;
3989                         }
3990
3991                         if (found != 0)
3992                         {
3993                                 hint_ereport(str,
3994                                                          ("Relation name \"%s\" is ambiguous.",
3995                                                           aliasname));
3996                                 return -1;
3997                         }
3998
3999                         found = i;
4000                         break;
4001                 }
4002
4003         }
4004
4005         return found;
4006 }
4007
4008 /*
4009  * Return join hint which matches given joinrelids.
4010  */
4011 static JoinMethodHint *
4012 find_join_hint(Relids joinrelids)
4013 {
4014         List       *join_hint;
4015         ListCell   *l;
4016
4017         join_hint = current_hint_state->join_hint_level[bms_num_members(joinrelids)];
4018
4019         foreach(l, join_hint)
4020         {
4021                 JoinMethodHint *hint = (JoinMethodHint *) lfirst(l);
4022
4023                 if (bms_equal(joinrelids, hint->joinrelids))
4024                         return hint;
4025         }
4026
4027         return NULL;
4028 }
4029
4030 static Relids
4031 OuterInnerJoinCreate(OuterInnerRels *outer_inner, LeadingHint *leading_hint,
4032         PlannerInfo *root, List *initial_rels, HintState *hstate, int nbaserel)
4033 {
4034         OuterInnerRels *outer_rels;
4035         OuterInnerRels *inner_rels;
4036         Relids                  outer_relids;
4037         Relids                  inner_relids;
4038         Relids                  join_relids;
4039         JoinMethodHint *hint;
4040
4041         if (outer_inner->relation != NULL)
4042         {
4043                 return bms_make_singleton(
4044                                         find_relid_aliasname(root, outer_inner->relation,
4045                                                                                  initial_rels,
4046                                                                                  leading_hint->base.hint_str));
4047         }
4048
4049         outer_rels = lfirst(outer_inner->outer_inner_pair->head);
4050         inner_rels = lfirst(outer_inner->outer_inner_pair->tail);
4051
4052         outer_relids = OuterInnerJoinCreate(outer_rels,
4053                                                                                 leading_hint,
4054                                                                                 root,
4055                                                                                 initial_rels,
4056                                                                                 hstate,
4057                                                                                 nbaserel);
4058         inner_relids = OuterInnerJoinCreate(inner_rels,
4059                                                                                 leading_hint,
4060                                                                                 root,
4061                                                                                 initial_rels,
4062                                                                                 hstate,
4063                                                                                 nbaserel);
4064
4065         join_relids = bms_add_members(outer_relids, inner_relids);
4066
4067         if (bms_num_members(join_relids) > nbaserel)
4068                 return join_relids;
4069
4070         /*
4071          * If we don't have join method hint, create new one for the
4072          * join combination with all join methods are enabled.
4073          */
4074         hint = find_join_hint(join_relids);
4075         if (hint == NULL)
4076         {
4077                 /*
4078                  * Here relnames is not set, since Relids bitmap is sufficient to
4079                  * control paths of this query afterward.
4080                  */
4081                 hint = (JoinMethodHint *) JoinMethodHintCreate(
4082                                         leading_hint->base.hint_str,
4083                                         HINT_LEADING,
4084                                         HINT_KEYWORD_LEADING);
4085                 hint->base.state = HINT_STATE_USED;
4086                 hint->nrels = bms_num_members(join_relids);
4087                 hint->enforce_mask = ENABLE_ALL_JOIN;
4088                 hint->joinrelids = bms_copy(join_relids);
4089                 hint->inner_nrels = bms_num_members(inner_relids);
4090                 hint->inner_joinrelids = bms_copy(inner_relids);
4091
4092                 hstate->join_hint_level[hint->nrels] =
4093                         lappend(hstate->join_hint_level[hint->nrels], hint);
4094         }
4095         else
4096         {
4097                 hint->inner_nrels = bms_num_members(inner_relids);
4098                 hint->inner_joinrelids = bms_copy(inner_relids);
4099         }
4100
4101         return join_relids;
4102 }
4103
4104 static Relids
4105 create_bms_of_relids(Hint *base, PlannerInfo *root, List *initial_rels,
4106                 int nrels, char **relnames)
4107 {
4108         int             relid;
4109         Relids  relids = NULL;
4110         int             j;
4111         char   *relname;
4112
4113         for (j = 0; j < nrels; j++)
4114         {
4115                 relname = relnames[j];
4116
4117                 relid = find_relid_aliasname(root, relname, initial_rels,
4118                                                                          base->hint_str);
4119
4120                 if (relid == -1)
4121                         base->state = HINT_STATE_ERROR;
4122
4123                 /*
4124                  * the aliasname is not found(relid == 0) or same aliasname was used
4125                  * multiple times in a query(relid == -1)
4126                  */
4127                 if (relid <= 0)
4128                 {
4129                         relids = NULL;
4130                         break;
4131                 }
4132                 if (bms_is_member(relid, relids))
4133                 {
4134                         hint_ereport(base->hint_str,
4135                                                  ("Relation name \"%s\" is duplicated.", relname));
4136                         base->state = HINT_STATE_ERROR;
4137                         break;
4138                 }
4139
4140                 relids = bms_add_member(relids, relid);
4141         }
4142         return relids;
4143 }
4144 /*
4145  * Transform join method hint into handy form.
4146  *
4147  *   - create bitmap of relids from alias names, to make it easier to check
4148  *     whether a join path matches a join method hint.
4149  *   - add join method hints which are necessary to enforce join order
4150  *     specified by Leading hint
4151  */
4152 static bool
4153 transform_join_hints(HintState *hstate, PlannerInfo *root, int nbaserel,
4154                 List *initial_rels, JoinMethodHint **join_method_hints)
4155 {
4156         int                             i;
4157         int                             relid;
4158         Relids                  joinrelids;
4159         int                             njoinrels;
4160         ListCell           *l;
4161         char               *relname;
4162         LeadingHint        *lhint = NULL;
4163
4164         /*
4165          * Create bitmap of relids from alias names for each join method hint.
4166          * Bitmaps are more handy than strings in join searching.
4167          */
4168         for (i = 0; i < hstate->num_hints[HINT_TYPE_JOIN_METHOD]; i++)
4169         {
4170                 JoinMethodHint *hint = hstate->join_hints[i];
4171
4172                 if (!hint_state_enabled(hint) || hint->nrels > nbaserel)
4173                         continue;
4174
4175                 hint->joinrelids = create_bms_of_relids(&(hint->base), root,
4176                                                                          initial_rels, hint->nrels, hint->relnames);
4177
4178                 if (hint->joinrelids == NULL || hint->base.state == HINT_STATE_ERROR)
4179                         continue;
4180
4181                 hstate->join_hint_level[hint->nrels] =
4182                         lappend(hstate->join_hint_level[hint->nrels], hint);
4183         }
4184
4185         /*
4186          * Create bitmap of relids from alias names for each rows hint.
4187          * Bitmaps are more handy than strings in join searching.
4188          */
4189         for (i = 0; i < hstate->num_hints[HINT_TYPE_ROWS]; i++)
4190         {
4191                 RowsHint *hint = hstate->rows_hints[i];
4192
4193                 if (!hint_state_enabled(hint) || hint->nrels > nbaserel)
4194                         continue;
4195
4196                 hint->joinrelids = create_bms_of_relids(&(hint->base), root,
4197                                                                          initial_rels, hint->nrels, hint->relnames);
4198         }
4199
4200         /* Do nothing if no Leading hint was supplied. */
4201         if (hstate->num_hints[HINT_TYPE_LEADING] == 0)
4202                 return false;
4203
4204         /*
4205          * Decide whether to use Leading hint
4206          */
4207         for (i = 0; i < hstate->num_hints[HINT_TYPE_LEADING]; i++)
4208         {
4209                 LeadingHint        *leading_hint = (LeadingHint *)hstate->leading_hint[i];
4210                 Relids                  relids;
4211
4212                 if (leading_hint->base.state == HINT_STATE_ERROR)
4213                         continue;
4214
4215                 relid = 0;
4216                 relids = NULL;
4217
4218                 foreach(l, leading_hint->relations)
4219                 {
4220                         relname = (char *)lfirst(l);;
4221
4222                         relid = find_relid_aliasname(root, relname, initial_rels,
4223                                                                                  leading_hint->base.hint_str);
4224                         if (relid == -1)
4225                                 leading_hint->base.state = HINT_STATE_ERROR;
4226
4227                         if (relid <= 0)
4228                                 break;
4229
4230                         if (bms_is_member(relid, relids))
4231                         {
4232                                 hint_ereport(leading_hint->base.hint_str,
4233                                                          ("Relation name \"%s\" is duplicated.", relname));
4234                                 leading_hint->base.state = HINT_STATE_ERROR;
4235                                 break;
4236                         }
4237
4238                         relids = bms_add_member(relids, relid);
4239                 }
4240
4241                 if (relid <= 0 || leading_hint->base.state == HINT_STATE_ERROR)
4242                         continue;
4243
4244                 if (lhint != NULL)
4245                 {
4246                         hint_ereport(lhint->base.hint_str,
4247                                  ("Conflict %s hint.", HintTypeName[lhint->base.type]));
4248                         lhint->base.state = HINT_STATE_DUPLICATION;
4249                 }
4250                 leading_hint->base.state = HINT_STATE_USED;
4251                 lhint = leading_hint;
4252         }
4253
4254         /* check to exist Leading hint marked with 'used'. */
4255         if (lhint == NULL)
4256                 return false;
4257
4258         /*
4259          * We need join method hints which fit specified join order in every join
4260          * level.  For example, Leading(A B C) virtually requires following join
4261          * method hints, if no join method hint supplied:
4262          *   - level 1: none
4263          *   - level 2: NestLoop(A B), MergeJoin(A B), HashJoin(A B)
4264          *   - level 3: NestLoop(A B C), MergeJoin(A B C), HashJoin(A B C)
4265          *
4266          * If we already have join method hint which fits specified join order in
4267          * that join level, we leave it as-is and don't add new hints.
4268          */
4269         joinrelids = NULL;
4270         njoinrels = 0;
4271         if (lhint->outer_inner == NULL)
4272         {
4273                 foreach(l, lhint->relations)
4274                 {
4275                         JoinMethodHint *hint;
4276
4277                         relname = (char *)lfirst(l);
4278
4279                         /*
4280                          * Find relid of the relation which has given name.  If we have the
4281                          * name given in Leading hint multiple times in the join, nothing to
4282                          * do.
4283                          */
4284                         relid = find_relid_aliasname(root, relname, initial_rels,
4285                                                                                  hstate->hint_str);
4286
4287                         /* Create bitmap of relids for current join level. */
4288                         joinrelids = bms_add_member(joinrelids, relid);
4289                         njoinrels++;
4290
4291                         /* We never have join method hint for single relation. */
4292                         if (njoinrels < 2)
4293                                 continue;
4294
4295                         /*
4296                          * If we don't have join method hint, create new one for the
4297                          * join combination with all join methods are enabled.
4298                          */
4299                         hint = find_join_hint(joinrelids);
4300                         if (hint == NULL)
4301                         {
4302                                 /*
4303                                  * Here relnames is not set, since Relids bitmap is sufficient
4304                                  * to control paths of this query afterward.
4305                                  */
4306                                 hint = (JoinMethodHint *) JoinMethodHintCreate(
4307                                                                                         lhint->base.hint_str,
4308                                                                                         HINT_LEADING,
4309                                                                                         HINT_KEYWORD_LEADING);
4310                                 hint->base.state = HINT_STATE_USED;
4311                                 hint->nrels = njoinrels;
4312                                 hint->enforce_mask = ENABLE_ALL_JOIN;
4313                                 hint->joinrelids = bms_copy(joinrelids);
4314                         }
4315
4316                         join_method_hints[njoinrels] = hint;
4317
4318                         if (njoinrels >= nbaserel)
4319                                 break;
4320                 }
4321                 bms_free(joinrelids);
4322
4323                 if (njoinrels < 2)
4324                         return false;
4325
4326                 /*
4327                  * Delete all join hints which have different combination from Leading
4328                  * hint.
4329                  */
4330                 for (i = 2; i <= njoinrels; i++)
4331                 {
4332                         list_free(hstate->join_hint_level[i]);
4333
4334                         hstate->join_hint_level[i] = lappend(NIL, join_method_hints[i]);
4335                 }
4336         }
4337         else
4338         {
4339                 joinrelids = OuterInnerJoinCreate(lhint->outer_inner,
4340                                                                                   lhint,
4341                                           root,
4342                                           initial_rels,
4343                                                                                   hstate,
4344                                                                                   nbaserel);
4345
4346                 njoinrels = bms_num_members(joinrelids);
4347                 Assert(njoinrels >= 2);
4348
4349                 /*
4350                  * Delete all join hints which have different combination from Leading
4351                  * hint.
4352                  */
4353                 for (i = 2;i <= njoinrels; i++)
4354                 {
4355                         if (hstate->join_hint_level[i] != NIL)
4356                         {
4357                                 ListCell *prev = NULL;
4358                                 ListCell *next = NULL;
4359                                 for(l = list_head(hstate->join_hint_level[i]); l; l = next)
4360                                 {
4361
4362                                         JoinMethodHint *hint = (JoinMethodHint *)lfirst(l);
4363
4364                                         next = lnext(l);
4365
4366                                         if (hint->inner_nrels == 0 &&
4367                                                 !(bms_intersect(hint->joinrelids, joinrelids) == NULL ||
4368                                                   bms_equal(bms_union(hint->joinrelids, joinrelids),
4369                                                   hint->joinrelids)))
4370                                         {
4371                                                 hstate->join_hint_level[i] =
4372                                                         list_delete_cell(hstate->join_hint_level[i], l,
4373                                                                                          prev);
4374                                         }
4375                                         else
4376                                                 prev = l;
4377                                 }
4378                         }
4379                 }
4380
4381                 bms_free(joinrelids);
4382         }
4383
4384         if (hint_state_enabled(lhint))
4385         {
4386                 set_join_config_options(DISABLE_ALL_JOIN, current_hint_state->context);
4387                 return true;
4388         }
4389         return false;
4390 }
4391
4392 /*
4393  * wrapper of make_join_rel()
4394  *
4395  * call make_join_rel() after changing enable_* parameters according to given
4396  * hints.
4397  */
4398 static RelOptInfo *
4399 make_join_rel_wrapper(PlannerInfo *root, RelOptInfo *rel1, RelOptInfo *rel2)
4400 {
4401         Relids                  joinrelids;
4402         JoinMethodHint *hint;
4403         RelOptInfo         *rel;
4404         int                             save_nestlevel;
4405
4406         joinrelids = bms_union(rel1->relids, rel2->relids);
4407         hint = find_join_hint(joinrelids);
4408         bms_free(joinrelids);
4409
4410         if (!hint)
4411                 return pg_hint_plan_make_join_rel(root, rel1, rel2);
4412
4413         if (hint->inner_nrels == 0)
4414         {
4415                 save_nestlevel = NewGUCNestLevel();
4416
4417                 set_join_config_options(hint->enforce_mask,
4418                                                                 current_hint_state->context);
4419
4420                 rel = pg_hint_plan_make_join_rel(root, rel1, rel2);
4421                 hint->base.state = HINT_STATE_USED;
4422
4423                 /*
4424                  * Restore the GUC variables we set above.
4425                  */
4426                 AtEOXact_GUC(true, save_nestlevel);
4427         }
4428         else
4429                 rel = pg_hint_plan_make_join_rel(root, rel1, rel2);
4430
4431         return rel;
4432 }
4433
4434 /*
4435  * TODO : comment
4436  */
4437 static void
4438 add_paths_to_joinrel_wrapper(PlannerInfo *root,
4439                                                          RelOptInfo *joinrel,
4440                                                          RelOptInfo *outerrel,
4441                                                          RelOptInfo *innerrel,
4442                                                          JoinType jointype,
4443                                                          SpecialJoinInfo *sjinfo,
4444                                                          List *restrictlist)
4445 {
4446         Relids                  joinrelids;
4447         JoinMethodHint *join_hint;
4448         int                             save_nestlevel;
4449
4450         joinrelids = bms_union(outerrel->relids, innerrel->relids);
4451         join_hint = find_join_hint(joinrelids);
4452         bms_free(joinrelids);
4453
4454         if (join_hint && join_hint->inner_nrels != 0)
4455         {
4456                 save_nestlevel = NewGUCNestLevel();
4457
4458                 if (bms_equal(join_hint->inner_joinrelids, innerrel->relids))
4459                 {
4460
4461                         set_join_config_options(join_hint->enforce_mask,
4462                                                                         current_hint_state->context);
4463
4464                         add_paths_to_joinrel(root, joinrel, outerrel, innerrel, jointype,
4465                                                                  sjinfo, restrictlist);
4466                         join_hint->base.state = HINT_STATE_USED;
4467                 }
4468                 else
4469                 {
4470                         set_join_config_options(DISABLE_ALL_JOIN,
4471                                                                         current_hint_state->context);
4472                         add_paths_to_joinrel(root, joinrel, outerrel, innerrel, jointype,
4473                                                                  sjinfo, restrictlist);
4474                 }
4475
4476                 /*
4477                  * Restore the GUC variables we set above.
4478                  */
4479                 AtEOXact_GUC(true, save_nestlevel);
4480         }
4481         else
4482                 add_paths_to_joinrel(root, joinrel, outerrel, innerrel, jointype,
4483                                                          sjinfo, restrictlist);
4484 }
4485
4486 static int
4487 get_num_baserels(List *initial_rels)
4488 {
4489         int                     nbaserel = 0;
4490         ListCell   *l;
4491
4492         foreach(l, initial_rels)
4493         {
4494                 RelOptInfo *rel = (RelOptInfo *) lfirst(l);
4495
4496                 if (rel->reloptkind == RELOPT_BASEREL)
4497                         nbaserel++;
4498                 else if (rel->reloptkind ==RELOPT_JOINREL)
4499                         nbaserel+= bms_num_members(rel->relids);
4500                 else
4501                 {
4502                         /* other values not expected here */
4503                         elog(ERROR, "unrecognized reloptkind type: %d", rel->reloptkind);
4504                 }
4505         }
4506
4507         return nbaserel;
4508 }
4509
4510 static RelOptInfo *
4511 pg_hint_plan_join_search(PlannerInfo *root, int levels_needed,
4512                                                  List *initial_rels)
4513 {
4514         JoinMethodHint    **join_method_hints;
4515         int                                     nbaserel;
4516         RelOptInfo                 *rel;
4517         int                                     i;
4518         bool                            leading_hint_enable;
4519
4520         /*
4521          * Use standard planner (or geqo planner) if pg_hint_plan is disabled or no
4522          * valid hint is supplied or current nesting depth is nesting depth of SPI
4523          * calls.
4524          */
4525         if (!current_hint_state || hint_inhibit_level > 0)
4526         {
4527                 if (prev_join_search)
4528                         return (*prev_join_search) (root, levels_needed, initial_rels);
4529                 else if (enable_geqo && levels_needed >= geqo_threshold)
4530                         return geqo(root, levels_needed, initial_rels);
4531                 else
4532                         return standard_join_search(root, levels_needed, initial_rels);
4533         }
4534
4535         /*
4536          * In the case using GEQO, only scan method hints and Set hints have
4537          * effect.  Join method and join order is not controllable by hints.
4538          */
4539         if (enable_geqo && levels_needed >= geqo_threshold)
4540                 return geqo(root, levels_needed, initial_rels);
4541
4542         nbaserel = get_num_baserels(initial_rels);
4543         current_hint_state->join_hint_level =
4544                 palloc0(sizeof(List *) * (nbaserel + 1));
4545         join_method_hints = palloc0(sizeof(JoinMethodHint *) * (nbaserel + 1));
4546
4547         leading_hint_enable = transform_join_hints(current_hint_state,
4548                                                                                            root, nbaserel,
4549                                                                                            initial_rels, join_method_hints);
4550
4551         rel = pg_hint_plan_standard_join_search(root, levels_needed, initial_rels);
4552
4553         /*
4554          * Adjust number of parallel workers of the result rel to the largest
4555          * number of the component paths.
4556          */
4557         if (current_hint_state->num_hints[HINT_TYPE_PARALLEL] > 0)
4558         {
4559                 ListCell   *lc;
4560                 int             nworkers = 0;
4561
4562                 foreach (lc, initial_rels)
4563                 {
4564                         ListCell *lcp;
4565                         RelOptInfo *rel = (RelOptInfo *) lfirst(lc);
4566
4567                         foreach (lcp, rel->partial_pathlist)
4568                         {
4569                                 Path *path = (Path *) lfirst(lcp);
4570
4571                                 if (nworkers < path-> parallel_workers)
4572                                         nworkers = path-> parallel_workers;
4573                         }
4574                 }
4575
4576                 foreach (lc, rel->partial_pathlist)
4577                 {
4578                         Path *path = (Path *) lfirst(lc);
4579
4580                         if (path->parallel_safe && path->parallel_workers < nworkers)
4581                                 path->parallel_workers = nworkers;
4582                 }
4583         }
4584
4585         for (i = 2; i <= nbaserel; i++)
4586         {
4587                 list_free(current_hint_state->join_hint_level[i]);
4588
4589                 /* free Leading hint only */
4590                 if (join_method_hints[i] != NULL &&
4591                         join_method_hints[i]->enforce_mask == ENABLE_ALL_JOIN)
4592                         JoinMethodHintDelete(join_method_hints[i]);
4593         }
4594         pfree(current_hint_state->join_hint_level);
4595         pfree(join_method_hints);
4596
4597         if (leading_hint_enable)
4598                 set_join_config_options(current_hint_state->init_join_mask,
4599                                                                 current_hint_state->context);
4600
4601         return rel;
4602 }
4603
4604 /*
4605  * Force number of wokers if instructed by hint
4606  */
4607 void
4608 pg_hint_plan_set_rel_pathlist(PlannerInfo * root, RelOptInfo *rel,
4609                                                           Index rti, RangeTblEntry *rte)
4610 {
4611         ParallelHint   *phint;
4612         ListCell           *l;
4613         int                             found_hints;
4614
4615         /* call the previous hook */
4616         if (prev_set_rel_pathlist)
4617                 prev_set_rel_pathlist(root, rel, rti, rte);
4618
4619         /* Nothing to do if no hint available */
4620         if (current_hint_state == NULL)
4621                 return;
4622
4623         /* Don't touch dummy rels. */
4624         if (IS_DUMMY_REL(rel))
4625                 return;
4626
4627         /*
4628          * We can accept only plain relations, foreign tables and table saples are
4629          * also unacceptable. See set_rel_pathlist.
4630          */
4631         if ((rel->rtekind != RTE_RELATION &&
4632                  rel->rtekind != RTE_SUBQUERY)||
4633                 rte->relkind == RELKIND_FOREIGN_TABLE ||
4634                 rte->tablesample != NULL)
4635                 return;
4636
4637         /*
4638          * Even though UNION ALL node doesn't have particular name so usually it is
4639          * unhintable, turn on parallel when it contains parallel nodes.
4640          */
4641         if (rel->rtekind == RTE_SUBQUERY)
4642         {
4643                 ListCell *lc;
4644                 bool    inhibit_nonparallel = false;
4645
4646                 if (rel->partial_pathlist == NIL)
4647                         return;
4648
4649                 foreach(lc, rel->partial_pathlist)
4650                 {
4651                         ListCell *lcp;
4652                         AppendPath *apath = (AppendPath *) lfirst(lc);
4653                         int             parallel_workers = 0;
4654
4655                         if (!IsA(apath, AppendPath))
4656                                 continue;
4657
4658                         foreach (lcp, apath->subpaths)
4659                         {
4660                                 Path *spath = (Path *) lfirst(lcp);
4661
4662                                 if (spath->parallel_aware &&
4663                                         parallel_workers < spath->parallel_workers)
4664                                         parallel_workers = spath->parallel_workers;
4665                         }
4666
4667                         apath->path.parallel_workers = parallel_workers;
4668                         inhibit_nonparallel = true;
4669                 }
4670
4671                 if (inhibit_nonparallel)
4672                 {
4673                         ListCell *lc;
4674
4675                         foreach(lc, rel->pathlist)
4676                         {
4677                                 Path *path = (Path *) lfirst(lc);
4678
4679                                 if (path->startup_cost < disable_cost)
4680                                 {
4681                                         path->startup_cost += disable_cost;
4682                                         path->total_cost += disable_cost;
4683                                 }
4684                         }
4685                 }
4686
4687                 return;
4688         }
4689
4690         /* We cannot handle if this requires an outer */
4691         if (rel->lateral_relids)
4692                 return;
4693
4694         /* Return if this relation gets no enfocement */
4695         if ((found_hints = setup_hint_enforcement(root, rel, NULL, &phint)) == 0)
4696                 return;
4697
4698         /* Here, we regenerate paths with the current hint restriction */
4699         if (found_hints & HINT_BM_SCAN_METHOD || found_hints & HINT_BM_PARALLEL)
4700         {
4701                 /*
4702                  * When hint is specified on non-parent relations, discard existing
4703                  * paths and regenerate based on the hint considered. Otherwise we
4704                  * already have hinted child paths then just adjust the number of
4705                  * planned number of workers.
4706                  */
4707                 if (root->simple_rte_array[rel->relid]->inh)
4708                 {
4709                         /* enforce number of workers if requested */
4710                         if (phint && phint->force_parallel)
4711                         {
4712                                 if (phint->nworkers == 0)
4713                                 {
4714                                         list_free_deep(rel->partial_pathlist);
4715                                         rel->partial_pathlist = NIL;
4716                                 }
4717                                 else
4718                                 {
4719                                         /* prioritize partial paths */
4720                                         foreach (l, rel->partial_pathlist)
4721                                         {
4722                                                 Path *ppath = (Path *) lfirst(l);
4723
4724                                                 if (ppath->parallel_safe)
4725                                                 {
4726                                                         ppath->parallel_workers = phint->nworkers;
4727                                                         ppath->startup_cost = 0;
4728                                                         ppath->total_cost = 0;
4729                                                 }
4730                                         }
4731
4732                                         /* disable non-partial paths */
4733                                         foreach (l, rel->pathlist)
4734                                         {
4735                                                 Path *ppath = (Path *) lfirst(l);
4736
4737                                                 if (ppath->startup_cost < disable_cost)
4738                                                 {
4739                                                         ppath->startup_cost += disable_cost;
4740                                                         ppath->total_cost += disable_cost;
4741                                                 }
4742                                         }
4743                                 }
4744                         }
4745                 }
4746                 else
4747                 {
4748                         /* Just discard all the paths considered so far */
4749                         list_free_deep(rel->pathlist);
4750                         rel->pathlist = NIL;
4751                         list_free_deep(rel->partial_pathlist);
4752                         rel->partial_pathlist = NIL;
4753
4754                         /* Regenerate paths with the current enforcement */
4755                         set_plain_rel_pathlist(root, rel, rte);
4756
4757                         /* Additional work to enforce parallel query execution */
4758                         if (phint && phint->nworkers > 0)
4759                         {
4760                                 /*
4761                                  * For Parallel Append to be planned properly, we shouldn't set
4762                                  * the costs of non-partial paths to disable-value.  Lower the
4763                                  * priority of non-parallel paths by setting partial path costs
4764                                  * to 0 instead.
4765                                  */
4766                                 foreach (l, rel->partial_pathlist)
4767                                 {
4768                                         Path *path = (Path *) lfirst(l);
4769
4770                                         path->startup_cost = 0;
4771                                         path->total_cost = 0;
4772                                 }
4773
4774                                 /* enforce number of workers if requested */
4775                                 if (phint->force_parallel)
4776                                 {
4777                                         foreach (l, rel->partial_pathlist)
4778                                         {
4779                                                 Path *ppath = (Path *) lfirst(l);
4780
4781                                                 if (ppath->parallel_safe)
4782                                                         ppath->parallel_workers = phint->nworkers;
4783                                         }
4784                                 }
4785
4786                                 /* Generate gather paths */
4787                                 if (rel->reloptkind == RELOPT_BASEREL &&
4788                                         bms_membership(root->all_baserels) != BMS_SINGLETON)
4789                                         generate_gather_paths(root, rel, false);
4790                         }
4791                 }
4792         }
4793
4794         reset_hint_enforcement();
4795 }
4796
4797 /*
4798  * set_rel_pathlist
4799  *        Build access paths for a base relation
4800  *
4801  * This function was copied and edited from set_rel_pathlist() in
4802  * src/backend/optimizer/path/allpaths.c in order not to copy other static
4803  * functions not required here.
4804  */
4805 static void
4806 set_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
4807                                  Index rti, RangeTblEntry *rte)
4808 {
4809         if (IS_DUMMY_REL(rel))
4810         {
4811                 /* We already proved the relation empty, so nothing more to do */
4812         }
4813         else if (rte->inh)
4814         {
4815                 /* It's an "append relation", process accordingly */
4816                 set_append_rel_pathlist(root, rel, rti, rte);
4817         }
4818         else
4819         {
4820                 if (rel->rtekind == RTE_RELATION)
4821                 {
4822                         if (rte->relkind == RELKIND_RELATION)
4823                         {
4824                                 if(rte->tablesample != NULL)
4825                                         elog(ERROR, "sampled relation is not supported");
4826
4827                                 /* Plain relation */
4828                                 set_plain_rel_pathlist(root, rel, rte);
4829                         }
4830                         else
4831                                 elog(ERROR, "unexpected relkind: %c", rte->relkind);
4832                 }
4833                 else
4834                         elog(ERROR, "unexpected rtekind: %d", (int) rel->rtekind);
4835         }
4836
4837         /*
4838          * Allow a plugin to editorialize on the set of Paths for this base
4839          * relation.  It could add new paths (such as CustomPaths) by calling
4840          * add_path(), or delete or modify paths added by the core code.
4841          */
4842         if (set_rel_pathlist_hook)
4843                 (*set_rel_pathlist_hook) (root, rel, rti, rte);
4844
4845         /* Now find the cheapest of the paths for this rel */
4846         set_cheapest(rel);
4847 }
4848
4849 /*
4850  * stmt_beg callback is called when each query in PL/pgSQL function is about
4851  * to be executed.  At that timing, we save query string in the global variable
4852  * plpgsql_query_string to use it in planner hook.  It's safe to use one global
4853  * variable for the purpose, because its content is only necessary until
4854  * planner hook is called for the query, so recursive PL/pgSQL function calls
4855  * don't harm this mechanism.
4856  */
4857 static void
4858 pg_hint_plan_plpgsql_stmt_beg(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
4859 {
4860         plpgsql_recurse_level++;
4861 }
4862
4863 /*
4864  * stmt_end callback is called then each query in PL/pgSQL function has
4865  * finished.  At that timing, we clear plpgsql_query_string to tell planner
4866  * hook that next call is not for a query written in PL/pgSQL block.
4867  */
4868 static void
4869 pg_hint_plan_plpgsql_stmt_end(PLpgSQL_execstate *estate, PLpgSQL_stmt *stmt)
4870 {
4871         plpgsql_recurse_level--;
4872 }
4873
4874 void plpgsql_query_erase_callback(ResourceReleasePhase phase,
4875                                                                   bool isCommit,
4876                                                                   bool isTopLevel,
4877                                                                   void *arg)
4878 {
4879         if (!isTopLevel || phase != RESOURCE_RELEASE_AFTER_LOCKS)
4880                 return;
4881         /* Cancel plpgsql nest level*/
4882         plpgsql_recurse_level = 0;
4883 }
4884
4885 #define standard_join_search pg_hint_plan_standard_join_search
4886 #define join_search_one_level pg_hint_plan_join_search_one_level
4887 #define make_join_rel make_join_rel_wrapper
4888 #include "core.c"
4889
4890 #undef make_join_rel
4891 #define make_join_rel pg_hint_plan_make_join_rel
4892 #define add_paths_to_joinrel add_paths_to_joinrel_wrapper
4893 #include "make_join_rel.c"
4894
4895 #include "pg_stat_statements.c"