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