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