granicus.if.org Git - postgresql/blob - src/backend/optimizer/plan/setrefs.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * setrefs.c
   4  *        Post-processing of a completed plan tree: fix references to subplan
   5  *        vars, compute regproc values for operators, etc
   6  *
   7  * Portions Copyright (c) 1996-2015, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  *
  11  * IDENTIFICATION
  12  *        src/backend/optimizer/plan/setrefs.c
  13  *
  14  *-------------------------------------------------------------------------
  15  */
  16 #include "postgres.h"
  17
  18 #include "access/transam.h"
  19 #include "catalog/pg_type.h"
  20 #include "nodes/makefuncs.h"
  21 #include "nodes/nodeFuncs.h"
  22 #include "optimizer/pathnode.h"
  23 #include "optimizer/planmain.h"
  24 #include "optimizer/planner.h"
  25 #include "optimizer/tlist.h"
  26 #include "tcop/utility.h"
  27 #include "utils/lsyscache.h"
  28 #include "utils/syscache.h"
  29
  30
  31 typedef struct
  32 {
  33         Index           varno;                  /* RT index of Var */
  34         AttrNumber      varattno;               /* attr number of Var */
  35         AttrNumber      resno;                  /* TLE position of Var */
  36 } tlist_vinfo;
  37
  38 typedef struct
  39 {
  40         List       *tlist;                      /* underlying target list */
  41         int                     num_vars;               /* number of plain Var tlist entries */
  42         bool            has_ph_vars;    /* are there PlaceHolderVar entries? */
  43         bool            has_non_vars;   /* are there other entries? */
  44         tlist_vinfo vars[FLEXIBLE_ARRAY_MEMBER];        /* has num_vars entries */
  45 } indexed_tlist;
  46
  47 typedef struct
  48 {
  49         PlannerInfo *root;
  50         int                     rtoffset;
  51 } fix_scan_expr_context;
  52
  53 typedef struct
  54 {
  55         PlannerInfo *root;
  56         indexed_tlist *outer_itlist;
  57         indexed_tlist *inner_itlist;
  58         Index           acceptable_rel;
  59         int                     rtoffset;
  60 } fix_join_expr_context;
  61
  62 typedef struct
  63 {
  64         PlannerInfo *root;
  65         indexed_tlist *subplan_itlist;
  66         Index           newvarno;
  67         int                     rtoffset;
  68 } fix_upper_expr_context;
  69
  70 /*
  71  * Check if a Const node is a regclass value.  We accept plain OID too,
  72  * since a regclass Const will get folded to that type if it's an argument
  73  * to oideq or similar operators.  (This might result in some extraneous
  74  * values in a plan's list of relation dependencies, but the worst result
  75  * would be occasional useless replans.)
  76  */
  77 #define ISREGCLASSCONST(con) \
  78         (((con)->consttype == REGCLASSOID || (con)->consttype == OIDOID) && \
  79          !(con)->constisnull)
  80
  81 #define fix_scan_list(root, lst, rtoffset) \
  82         ((List *) fix_scan_expr(root, (Node *) (lst), rtoffset))
  83
  84 static void add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing);
  85 static void flatten_unplanned_rtes(PlannerGlobal *glob, RangeTblEntry *rte);
  86 static bool flatten_rtes_walker(Node *node, PlannerGlobal *glob);
  87 static void add_rte_to_flat_rtable(PlannerGlobal *glob, RangeTblEntry *rte);
  88 static Plan *set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset);
  89 static Plan *set_indexonlyscan_references(PlannerInfo *root,
  90                                                          IndexOnlyScan *plan,
  91                                                          int rtoffset);
  92 static Plan *set_subqueryscan_references(PlannerInfo *root,
  93                                                         SubqueryScan *plan,
  94                                                         int rtoffset);
  95 static bool trivial_subqueryscan(SubqueryScan *plan);
  96 static void set_foreignscan_references(PlannerInfo *root,
  97                                                    ForeignScan *fscan,
  98                                                    int rtoffset);
  99 static void set_customscan_references(PlannerInfo *root,
 100                                                   CustomScan *cscan,
 101                                                   int rtoffset);
 102 static Node *fix_scan_expr(PlannerInfo *root, Node *node, int rtoffset);
 103 static Node *fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context);
 104 static bool fix_scan_expr_walker(Node *node, fix_scan_expr_context *context);
 105 static void set_join_references(PlannerInfo *root, Join *join, int rtoffset);
 106 static void set_upper_references(PlannerInfo *root, Plan *plan, int rtoffset);
 107 static void set_dummy_tlist_references(Plan *plan, int rtoffset);
 108 static indexed_tlist *build_tlist_index(List *tlist);
 109 static Var *search_indexed_tlist_for_var(Var *var,
 110                                                          indexed_tlist *itlist,
 111                                                          Index newvarno,
 112                                                          int rtoffset);
 113 static Var *search_indexed_tlist_for_non_var(Node *node,
 114                                                                  indexed_tlist *itlist,
 115                                                                  Index newvarno);
 116 static Var *search_indexed_tlist_for_sortgroupref(Node *node,
 117                                                                           Index sortgroupref,
 118                                                                           indexed_tlist *itlist,
 119                                                                           Index newvarno);
 120 static List *fix_join_expr(PlannerInfo *root,
 121                           List *clauses,
 122                           indexed_tlist *outer_itlist,
 123                           indexed_tlist *inner_itlist,
 124                           Index acceptable_rel, int rtoffset);
 125 static Node *fix_join_expr_mutator(Node *node,
 126                                           fix_join_expr_context *context);
 127 static Node *fix_upper_expr(PlannerInfo *root,
 128                            Node *node,
 129                            indexed_tlist *subplan_itlist,
 130                            Index newvarno,
 131                            int rtoffset);
 132 static Node *fix_upper_expr_mutator(Node *node,
 133                                            fix_upper_expr_context *context);
 134 static List *set_returning_clause_references(PlannerInfo *root,
 135                                                                 List *rlist,
 136                                                                 Plan *topplan,
 137                                                                 Index resultRelation,
 138                                                                 int rtoffset);
 139 static bool fix_opfuncids_walker(Node *node, void *context);
 140 static bool extract_query_dependencies_walker(Node *node,
 141                                                                   PlannerInfo *context);
 142
 143
 144 /*****************************************************************************
 145  *
 146  *              SUBPLAN REFERENCES
 147  *
 148  *****************************************************************************/
 149
 150 /*
 151  * set_plan_references
 152  *
 153  * This is the final processing pass of the planner/optimizer.  The plan
 154  * tree is complete; we just have to adjust some representational details
 155  * for the convenience of the executor:
 156  *
 157  * 1. We flatten the various subquery rangetables into a single list, and
 158  * zero out RangeTblEntry fields that are not useful to the executor.
 159  *
 160  * 2. We adjust Vars in scan nodes to be consistent with the flat rangetable.
 161  *
 162  * 3. We adjust Vars in upper plan nodes to refer to the outputs of their
 163  * subplans.
 164  *
 165  * 4. PARAM_MULTIEXPR Params are replaced by regular PARAM_EXEC Params,
 166  * now that we have finished planning all MULTIEXPR subplans.
 167  *
 168  * 5. We compute regproc OIDs for operators (ie, we look up the function
 169  * that implements each op).
 170  *
 171  * 6. We create lists of specific objects that the plan depends on.
 172  * This will be used by plancache.c to drive invalidation of cached plans.
 173  * Relation dependencies are represented by OIDs, and everything else by
 174  * PlanInvalItems (this distinction is motivated by the shared-inval APIs).
 175  * Currently, relations and user-defined functions are the only types of
 176  * objects that are explicitly tracked this way.
 177  *
 178  * We also perform one final optimization step, which is to delete
 179  * SubqueryScan plan nodes that aren't doing anything useful (ie, have
 180  * no qual and a no-op targetlist).  The reason for doing this last is that
 181  * it can't readily be done before set_plan_references, because it would
 182  * break set_upper_references: the Vars in the subquery's top tlist
 183  * wouldn't match up with the Vars in the outer plan tree.  The SubqueryScan
 184  * serves a necessary function as a buffer between outer query and subquery
 185  * variable numbering ... but after we've flattened the rangetable this is
 186  * no longer a problem, since then there's only one rtindex namespace.
 187  *
 188  * set_plan_references recursively traverses the whole plan tree.
 189  *
 190  * The return value is normally the same Plan node passed in, but can be
 191  * different when the passed-in Plan is a SubqueryScan we decide isn't needed.
 192  *
 193  * The flattened rangetable entries are appended to root->glob->finalrtable.
 194  * Also, rowmarks entries are appended to root->glob->finalrowmarks, and the
 195  * RT indexes of ModifyTable result relations to root->glob->resultRelations.
 196  * Plan dependencies are appended to root->glob->relationOids (for relations)
 197  * and root->glob->invalItems (for everything else).
 198  *
 199  * Notice that we modify Plan nodes in-place, but use expression_tree_mutator
 200  * to process targetlist and qual expressions.  We can assume that the Plan
 201  * nodes were just built by the planner and are not multiply referenced, but
 202  * it's not so safe to assume that for expression tree nodes.
 203  */
 204 Plan *
 205 set_plan_references(PlannerInfo *root, Plan *plan)
 206 {
 207         PlannerGlobal *glob = root->glob;
 208         int                     rtoffset = list_length(glob->finalrtable);
 209         ListCell   *lc;
 210
 211         /*
 212          * Add all the query's RTEs to the flattened rangetable.  The live ones
 213          * will have their rangetable indexes increased by rtoffset.  (Additional
 214          * RTEs, not referenced by the Plan tree, might get added after those.)
 215          */
 216         add_rtes_to_flat_rtable(root, false);
 217
 218         /*
 219          * Adjust RT indexes of PlanRowMarks and add to final rowmarks list
 220          */
 221         foreach(lc, root->rowMarks)
 222         {
 223                 PlanRowMark *rc = (PlanRowMark *) lfirst(lc);
 224                 PlanRowMark *newrc;
 225
 226                 Assert(IsA(rc, PlanRowMark));
 227
 228                 /* flat copy is enough since all fields are scalars */
 229                 newrc = (PlanRowMark *) palloc(sizeof(PlanRowMark));
 230                 memcpy(newrc, rc, sizeof(PlanRowMark));
 231
 232                 /* adjust indexes ... but *not* the rowmarkId */
 233                 newrc->rti += rtoffset;
 234                 newrc->prti += rtoffset;
 235
 236                 glob->finalrowmarks = lappend(glob->finalrowmarks, newrc);
 237         }
 238
 239         /* Now fix the Plan tree */
 240         return set_plan_refs(root, plan, rtoffset);
 241 }
 242
 243 /*
 244  * Extract RangeTblEntries from the plan's rangetable, and add to flat rtable
 245  *
 246  * This can recurse into subquery plans; "recursing" is true if so.
 247  */
 248 static void
 249 add_rtes_to_flat_rtable(PlannerInfo *root, bool recursing)
 250 {
 251         PlannerGlobal *glob = root->glob;
 252         Index           rti;
 253         ListCell   *lc;
 254
 255         /*
 256          * Add the query's own RTEs to the flattened rangetable.
 257          *
 258          * At top level, we must add all RTEs so that their indexes in the
 259          * flattened rangetable match up with their original indexes.  When
 260          * recursing, we only care about extracting relation RTEs.
 261          */
 262         foreach(lc, root->parse->rtable)
 263         {
 264                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
 265
 266                 if (!recursing || rte->rtekind == RTE_RELATION)
 267                         add_rte_to_flat_rtable(glob, rte);
 268         }
 269
 270         /*
 271          * If there are any dead subqueries, they are not referenced in the Plan
 272          * tree, so we must add RTEs contained in them to the flattened rtable
 273          * separately.  (If we failed to do this, the executor would not perform
 274          * expected permission checks for tables mentioned in such subqueries.)
 275          *
 276          * Note: this pass over the rangetable can't be combined with the previous
 277          * one, because that would mess up the numbering of the live RTEs in the
 278          * flattened rangetable.
 279          */
 280         rti = 1;
 281         foreach(lc, root->parse->rtable)
 282         {
 283                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
 284
 285                 /*
 286                  * We should ignore inheritance-parent RTEs: their contents have been
 287                  * pulled up into our rangetable already.  Also ignore any subquery
 288                  * RTEs without matching RelOptInfos, as they likewise have been
 289                  * pulled up.
 290                  */
 291                 if (rte->rtekind == RTE_SUBQUERY && !rte->inh &&
 292                         rti < root->simple_rel_array_size)
 293                 {
 294                         RelOptInfo *rel = root->simple_rel_array[rti];
 295
 296                         if (rel != NULL)
 297                         {
 298                                 Assert(rel->relid == rti);              /* sanity check on array */
 299
 300                                 /*
 301                                  * The subquery might never have been planned at all, if it
 302                                  * was excluded on the basis of self-contradictory constraints
 303                                  * in our query level.  In this case apply
 304                                  * flatten_unplanned_rtes.
 305                                  *
 306                                  * If it was planned but the plan is dummy, we assume that it
 307                                  * has been omitted from our plan tree (see
 308                                  * set_subquery_pathlist), and recurse to pull up its RTEs.
 309                                  *
 310                                  * Otherwise, it should be represented by a SubqueryScan node
 311                                  * somewhere in our plan tree, and we'll pull up its RTEs when
 312                                  * we process that plan node.
 313                                  *
 314                                  * However, if we're recursing, then we should pull up RTEs
 315                                  * whether the subplan is dummy or not, because we've found
 316                                  * that some upper query level is treating this one as dummy,
 317                                  * and so we won't scan this level's plan tree at all.
 318                                  */
 319                                 if (rel->subplan == NULL)
 320                                         flatten_unplanned_rtes(glob, rte);
 321                                 else if (recursing || is_dummy_plan(rel->subplan))
 322                                 {
 323                                         Assert(rel->subroot != NULL);
 324                                         add_rtes_to_flat_rtable(rel->subroot, true);
 325                                 }
 326                         }
 327                 }
 328                 rti++;
 329         }
 330 }
 331
 332 /*
 333  * Extract RangeTblEntries from a subquery that was never planned at all
 334  */
 335 static void
 336 flatten_unplanned_rtes(PlannerGlobal *glob, RangeTblEntry *rte)
 337 {
 338         /* Use query_tree_walker to find all RTEs in the parse tree */
 339         (void) query_tree_walker(rte->subquery,
 340                                                          flatten_rtes_walker,
 341                                                          (void *) glob,
 342                                                          QTW_EXAMINE_RTES);
 343 }
 344
 345 static bool
 346 flatten_rtes_walker(Node *node, PlannerGlobal *glob)
 347 {
 348         if (node == NULL)
 349                 return false;
 350         if (IsA(node, RangeTblEntry))
 351         {
 352                 RangeTblEntry *rte = (RangeTblEntry *) node;
 353
 354                 /* As above, we need only save relation RTEs */
 355                 if (rte->rtekind == RTE_RELATION)
 356                         add_rte_to_flat_rtable(glob, rte);
 357                 return false;
 358         }
 359         if (IsA(node, Query))
 360         {
 361                 /* Recurse into subselects */
 362                 return query_tree_walker((Query *) node,
 363                                                                  flatten_rtes_walker,
 364                                                                  (void *) glob,
 365                                                                  QTW_EXAMINE_RTES);
 366         }
 367         return expression_tree_walker(node, flatten_rtes_walker,
 368                                                                   (void *) glob);
 369 }
 370
 371 /*
 372  * Add (a copy of) the given RTE to the final rangetable
 373  *
 374  * In the flat rangetable, we zero out substructure pointers that are not
 375  * needed by the executor; this reduces the storage space and copying cost
 376  * for cached plans.  We keep only the alias and eref Alias fields, which are
 377  * needed by EXPLAIN, and the selectedCols, insertedCols and updatedCols
 378  * bitmaps, which are needed for executor-startup permissions checking and for
 379  * trigger event checking.
 380  */
 381 static void
 382 add_rte_to_flat_rtable(PlannerGlobal *glob, RangeTblEntry *rte)
 383 {
 384         RangeTblEntry *newrte;
 385
 386         /* flat copy to duplicate all the scalar fields */
 387         newrte = (RangeTblEntry *) palloc(sizeof(RangeTblEntry));
 388         memcpy(newrte, rte, sizeof(RangeTblEntry));
 389
 390         /* zap unneeded sub-structure */
 391         newrte->subquery = NULL;
 392         newrte->joinaliasvars = NIL;
 393         newrte->functions = NIL;
 394         newrte->values_lists = NIL;
 395         newrte->values_collations = NIL;
 396         newrte->ctecoltypes = NIL;
 397         newrte->ctecoltypmods = NIL;
 398         newrte->ctecolcollations = NIL;
 399
 400         glob->finalrtable = lappend(glob->finalrtable, newrte);
 401
 402         /*
 403          * Check for RT index overflow; it's very unlikely, but if it did happen,
 404          * the executor would get confused by varnos that match the special varno
 405          * values.
 406          */
 407         if (IS_SPECIAL_VARNO(list_length(glob->finalrtable)))
 408                 ereport(ERROR,
 409                                 (errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
 410                                  errmsg("too many range table entries")));
 411
 412         /*
 413          * If it's a plain relation RTE, add the table to relationOids.
 414          *
 415          * We do this even though the RTE might be unreferenced in the plan tree;
 416          * this would correspond to cases such as views that were expanded, child
 417          * tables that were eliminated by constraint exclusion, etc. Schema
 418          * invalidation on such a rel must still force rebuilding of the plan.
 419          *
 420          * Note we don't bother to avoid making duplicate list entries.  We could,
 421          * but it would probably cost more cycles than it would save.
 422          */
 423         if (newrte->rtekind == RTE_RELATION)
 424                 glob->relationOids = lappend_oid(glob->relationOids, newrte->relid);
 425 }
 426
 427 /*
 428  * set_plan_refs: recurse through the Plan nodes of a single subquery level
 429  */
 430 static Plan *
 431 set_plan_refs(PlannerInfo *root, Plan *plan, int rtoffset)
 432 {
 433         ListCell   *l;
 434
 435         if (plan == NULL)
 436                 return NULL;
 437
 438         /*
 439          * Plan-type-specific fixes
 440          */
 441         switch (nodeTag(plan))
 442         {
 443                 case T_SeqScan:
 444                         {
 445                                 SeqScan    *splan = (SeqScan *) plan;
 446
 447                                 splan->scanrelid += rtoffset;
 448                                 splan->plan.targetlist =
 449                                         fix_scan_list(root, splan->plan.targetlist, rtoffset);
 450                                 splan->plan.qual =
 451                                         fix_scan_list(root, splan->plan.qual, rtoffset);
 452                         }
 453                         break;
 454                 case T_SampleScan:
 455                         {
 456                                 SampleScan         *splan = (SampleScan *) plan;
 457
 458                                 splan->scanrelid += rtoffset;
 459                                 splan->plan.targetlist =
 460                                         fix_scan_list(root, splan->plan.targetlist, rtoffset);
 461                                 splan->plan.qual =
 462                                         fix_scan_list(root, splan->plan.qual, rtoffset);
 463                         }
 464                         break;
 465                 case T_IndexScan:
 466                         {
 467                                 IndexScan  *splan = (IndexScan *) plan;
 468
 469                                 splan->scan.scanrelid += rtoffset;
 470                                 splan->scan.plan.targetlist =
 471                                         fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
 472                                 splan->scan.plan.qual =
 473                                         fix_scan_list(root, splan->scan.plan.qual, rtoffset);
 474                                 splan->indexqual =
 475                                         fix_scan_list(root, splan->indexqual, rtoffset);
 476                                 splan->indexqualorig =
 477                                         fix_scan_list(root, splan->indexqualorig, rtoffset);
 478                                 splan->indexorderby =
 479                                         fix_scan_list(root, splan->indexorderby, rtoffset);
 480                                 splan->indexorderbyorig =
 481                                         fix_scan_list(root, splan->indexorderbyorig, rtoffset);
 482                         }
 483                         break;
 484                 case T_IndexOnlyScan:
 485                         {
 486                                 IndexOnlyScan *splan = (IndexOnlyScan *) plan;
 487
 488                                 return set_indexonlyscan_references(root, splan, rtoffset);
 489                         }
 490                         break;
 491                 case T_BitmapIndexScan:
 492                         {
 493                                 BitmapIndexScan *splan = (BitmapIndexScan *) plan;
 494
 495                                 splan->scan.scanrelid += rtoffset;
 496                                 /* no need to fix targetlist and qual */
 497                                 Assert(splan->scan.plan.targetlist == NIL);
 498                                 Assert(splan->scan.plan.qual == NIL);
 499                                 splan->indexqual =
 500                                         fix_scan_list(root, splan->indexqual, rtoffset);
 501                                 splan->indexqualorig =
 502                                         fix_scan_list(root, splan->indexqualorig, rtoffset);
 503                         }
 504                         break;
 505                 case T_BitmapHeapScan:
 506                         {
 507                                 BitmapHeapScan *splan = (BitmapHeapScan *) plan;
 508
 509                                 splan->scan.scanrelid += rtoffset;
 510                                 splan->scan.plan.targetlist =
 511                                         fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
 512                                 splan->scan.plan.qual =
 513                                         fix_scan_list(root, splan->scan.plan.qual, rtoffset);
 514                                 splan->bitmapqualorig =
 515                                         fix_scan_list(root, splan->bitmapqualorig, rtoffset);
 516                         }
 517                         break;
 518                 case T_TidScan:
 519                         {
 520                                 TidScan    *splan = (TidScan *) plan;
 521
 522                                 splan->scan.scanrelid += rtoffset;
 523                                 splan->scan.plan.targetlist =
 524                                         fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
 525                                 splan->scan.plan.qual =
 526                                         fix_scan_list(root, splan->scan.plan.qual, rtoffset);
 527                                 splan->tidquals =
 528                                         fix_scan_list(root, splan->tidquals, rtoffset);
 529                         }
 530                         break;
 531                 case T_SubqueryScan:
 532                         /* Needs special treatment, see comments below */
 533                         return set_subqueryscan_references(root,
 534                                                                                            (SubqueryScan *) plan,
 535                                                                                            rtoffset);
 536                 case T_FunctionScan:
 537                         {
 538                                 FunctionScan *splan = (FunctionScan *) plan;
 539
 540                                 splan->scan.scanrelid += rtoffset;
 541                                 splan->scan.plan.targetlist =
 542                                         fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
 543                                 splan->scan.plan.qual =
 544                                         fix_scan_list(root, splan->scan.plan.qual, rtoffset);
 545                                 splan->functions =
 546                                         fix_scan_list(root, splan->functions, rtoffset);
 547                         }
 548                         break;
 549                 case T_ValuesScan:
 550                         {
 551                                 ValuesScan *splan = (ValuesScan *) plan;
 552
 553                                 splan->scan.scanrelid += rtoffset;
 554                                 splan->scan.plan.targetlist =
 555                                         fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
 556                                 splan->scan.plan.qual =
 557                                         fix_scan_list(root, splan->scan.plan.qual, rtoffset);
 558                                 splan->values_lists =
 559                                         fix_scan_list(root, splan->values_lists, rtoffset);
 560                         }
 561                         break;
 562                 case T_CteScan:
 563                         {
 564                                 CteScan    *splan = (CteScan *) plan;
 565
 566                                 splan->scan.scanrelid += rtoffset;
 567                                 splan->scan.plan.targetlist =
 568                                         fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
 569                                 splan->scan.plan.qual =
 570                                         fix_scan_list(root, splan->scan.plan.qual, rtoffset);
 571                         }
 572                         break;
 573                 case T_WorkTableScan:
 574                         {
 575                                 WorkTableScan *splan = (WorkTableScan *) plan;
 576
 577                                 splan->scan.scanrelid += rtoffset;
 578                                 splan->scan.plan.targetlist =
 579                                         fix_scan_list(root, splan->scan.plan.targetlist, rtoffset);
 580                                 splan->scan.plan.qual =
 581                                         fix_scan_list(root, splan->scan.plan.qual, rtoffset);
 582                         }
 583                         break;
 584                 case T_ForeignScan:
 585                         set_foreignscan_references(root, (ForeignScan *) plan, rtoffset);
 586                         break;
 587                 case T_CustomScan:
 588                         set_customscan_references(root, (CustomScan *) plan, rtoffset);
 589                         break;
 590
 591                 case T_NestLoop:
 592                 case T_MergeJoin:
 593                 case T_HashJoin:
 594                         set_join_references(root, (Join *) plan, rtoffset);
 595                         break;
 596
 597                 case T_Hash:
 598                 case T_Material:
 599                 case T_Sort:
 600                 case T_Unique:
 601                 case T_SetOp:
 602
 603                         /*
 604                          * These plan types don't actually bother to evaluate their
 605                          * targetlists, because they just return their unmodified input
 606                          * tuples.  Even though the targetlist won't be used by the
 607                          * executor, we fix it up for possible use by EXPLAIN (not to
 608                          * mention ease of debugging --- wrong varnos are very confusing).
 609                          */
 610                         set_dummy_tlist_references(plan, rtoffset);
 611
 612                         /*
 613                          * Since these plan types don't check quals either, we should not
 614                          * find any qual expression attached to them.
 615                          */
 616                         Assert(plan->qual == NIL);
 617                         break;
 618                 case T_LockRows:
 619                         {
 620                                 LockRows   *splan = (LockRows *) plan;
 621
 622                                 /*
 623                                  * Like the plan types above, LockRows doesn't evaluate its
 624                                  * tlist or quals.  But we have to fix up the RT indexes in
 625                                  * its rowmarks.
 626                                  */
 627                                 set_dummy_tlist_references(plan, rtoffset);
 628                                 Assert(splan->plan.qual == NIL);
 629
 630                                 foreach(l, splan->rowMarks)
 631                                 {
 632                                         PlanRowMark *rc = (PlanRowMark *) lfirst(l);
 633
 634                                         rc->rti += rtoffset;
 635                                         rc->prti += rtoffset;
 636                                 }
 637                         }
 638                         break;
 639                 case T_Limit:
 640                         {
 641                                 Limit      *splan = (Limit *) plan;
 642
 643                                 /*
 644                                  * Like the plan types above, Limit doesn't evaluate its tlist
 645                                  * or quals.  It does have live expressions for limit/offset,
 646                                  * however; and those cannot contain subplan variable refs, so
 647                                  * fix_scan_expr works for them.
 648                                  */
 649                                 set_dummy_tlist_references(plan, rtoffset);
 650                                 Assert(splan->plan.qual == NIL);
 651
 652                                 splan->limitOffset =
 653                                         fix_scan_expr(root, splan->limitOffset, rtoffset);
 654                                 splan->limitCount =
 655                                         fix_scan_expr(root, splan->limitCount, rtoffset);
 656                         }
 657                         break;
 658                 case T_Agg:
 659                 case T_Group:
 660                         set_upper_references(root, plan, rtoffset);
 661                         break;
 662                 case T_WindowAgg:
 663                         {
 664                                 WindowAgg  *wplan = (WindowAgg *) plan;
 665
 666                                 set_upper_references(root, plan, rtoffset);
 667
 668                                 /*
 669                                  * Like Limit node limit/offset expressions, WindowAgg has
 670                                  * frame offset expressions, which cannot contain subplan
 671                                  * variable refs, so fix_scan_expr works for them.
 672                                  */
 673                                 wplan->startOffset =
 674                                         fix_scan_expr(root, wplan->startOffset, rtoffset);
 675                                 wplan->endOffset =
 676                                         fix_scan_expr(root, wplan->endOffset, rtoffset);
 677                         }
 678                         break;
 679                 case T_Result:
 680                         {
 681                                 Result     *splan = (Result *) plan;
 682
 683                                 /*
 684                                  * Result may or may not have a subplan; if not, it's more
 685                                  * like a scan node than an upper node.
 686                                  */
 687                                 if (splan->plan.lefttree != NULL)
 688                                         set_upper_references(root, plan, rtoffset);
 689                                 else
 690                                 {
 691                                         splan->plan.targetlist =
 692                                                 fix_scan_list(root, splan->plan.targetlist, rtoffset);
 693                                         splan->plan.qual =
 694                                                 fix_scan_list(root, splan->plan.qual, rtoffset);
 695                                 }
 696                                 /* resconstantqual can't contain any subplan variable refs */
 697                                 splan->resconstantqual =
 698                                         fix_scan_expr(root, splan->resconstantqual, rtoffset);
 699                         }
 700                         break;
 701                 case T_ModifyTable:
 702                         {
 703                                 ModifyTable *splan = (ModifyTable *) plan;
 704
 705                                 Assert(splan->plan.targetlist == NIL);
 706                                 Assert(splan->plan.qual == NIL);
 707
 708                                 splan->withCheckOptionLists =
 709                                         fix_scan_list(root, splan->withCheckOptionLists, rtoffset);
 710
 711                                 if (splan->returningLists)
 712                                 {
 713                                         List       *newRL = NIL;
 714                                         ListCell   *lcrl,
 715                                                            *lcrr,
 716                                                            *lcp;
 717
 718                                         /*
 719                                          * Pass each per-subplan returningList through
 720                                          * set_returning_clause_references().
 721                                          */
 722                                         Assert(list_length(splan->returningLists) == list_length(splan->resultRelations));
 723                                         Assert(list_length(splan->returningLists) == list_length(splan->plans));
 724                                         forthree(lcrl, splan->returningLists,
 725                                                          lcrr, splan->resultRelations,
 726                                                          lcp, splan->plans)
 727                                         {
 728                                                 List       *rlist = (List *) lfirst(lcrl);
 729                                                 Index           resultrel = lfirst_int(lcrr);
 730                                                 Plan       *subplan = (Plan *) lfirst(lcp);
 731
 732                                                 rlist = set_returning_clause_references(root,
 733                                                                                                                                 rlist,
 734                                                                                                                                 subplan,
 735                                                                                                                                 resultrel,
 736                                                                                                                                 rtoffset);
 737                                                 newRL = lappend(newRL, rlist);
 738                                         }
 739                                         splan->returningLists = newRL;
 740
 741                                         /*
 742                                          * Set up the visible plan targetlist as being the same as
 743                                          * the first RETURNING list. This is for the use of
 744                                          * EXPLAIN; the executor won't pay any attention to the
 745                                          * targetlist.  We postpone this step until here so that
 746                                          * we don't have to do set_returning_clause_references()
 747                                          * twice on identical targetlists.
 748                                          */
 749                                         splan->plan.targetlist = copyObject(linitial(newRL));
 750                                 }
 751
 752                                 /*
 753                                  * We treat ModifyTable with ON CONFLICT as a form of 'pseudo
 754                                  * join', where the inner side is the EXCLUDED tuple.
 755                                  * Therefore use fix_join_expr to setup the relevant variables
 756                                  * to INNER_VAR. We explicitly don't create any OUTER_VARs as
 757                                  * those are already used by RETURNING and it seems better to
 758                                  * be non-conflicting.
 759                                  */
 760                                 if (splan->onConflictSet)
 761                                 {
 762                                         indexed_tlist *itlist;
 763
 764                                         itlist = build_tlist_index(splan->exclRelTlist);
 765
 766                                         splan->onConflictSet =
 767                                                 fix_join_expr(root, splan->onConflictSet,
 768                                                                           NULL, itlist,
 769                                                                           linitial_int(splan->resultRelations),
 770                                                                           rtoffset);
 771
 772                                         splan->onConflictWhere = (Node *)
 773                                                 fix_join_expr(root, (List *) splan->onConflictWhere,
 774                                                                           NULL, itlist,
 775                                                                           linitial_int(splan->resultRelations),
 776                                                                           rtoffset);
 777
 778                                         splan->exclRelTlist =
 779                                                 fix_scan_list(root, splan->exclRelTlist, rtoffset);
 780                                 }
 781
 782                                 splan->nominalRelation += rtoffset;
 783                                 splan->exclRelRTI += rtoffset;
 784
 785                                 foreach(l, splan->resultRelations)
 786                                 {
 787                                         lfirst_int(l) += rtoffset;
 788                                 }
 789                                 foreach(l, splan->rowMarks)
 790                                 {
 791                                         PlanRowMark *rc = (PlanRowMark *) lfirst(l);
 792
 793                                         rc->rti += rtoffset;
 794                                         rc->prti += rtoffset;
 795                                 }
 796                                 foreach(l, splan->plans)
 797                                 {
 798                                         lfirst(l) = set_plan_refs(root,
 799                                                                                           (Plan *) lfirst(l),
 800                                                                                           rtoffset);
 801                                 }
 802
 803                                 /*
 804                                  * Append this ModifyTable node's final result relation RT
 805                                  * index(es) to the global list for the plan, and set its
 806                                  * resultRelIndex to reflect their starting position in the
 807                                  * global list.
 808                                  */
 809                                 splan->resultRelIndex = list_length(root->glob->resultRelations);
 810                                 root->glob->resultRelations =
 811                                         list_concat(root->glob->resultRelations,
 812                                                                 list_copy(splan->resultRelations));
 813                         }
 814                         break;
 815                 case T_Append:
 816                         {
 817                                 Append     *splan = (Append *) plan;
 818
 819                                 /*
 820                                  * Append, like Sort et al, doesn't actually evaluate its
 821                                  * targetlist or check quals.
 822                                  */
 823                                 set_dummy_tlist_references(plan, rtoffset);
 824                                 Assert(splan->plan.qual == NIL);
 825                                 foreach(l, splan->appendplans)
 826                                 {
 827                                         lfirst(l) = set_plan_refs(root,
 828                                                                                           (Plan *) lfirst(l),
 829                                                                                           rtoffset);
 830                                 }
 831                         }
 832                         break;
 833                 case T_MergeAppend:
 834                         {
 835                                 MergeAppend *splan = (MergeAppend *) plan;
 836
 837                                 /*
 838                                  * MergeAppend, like Sort et al, doesn't actually evaluate its
 839                                  * targetlist or check quals.
 840                                  */
 841                                 set_dummy_tlist_references(plan, rtoffset);
 842                                 Assert(splan->plan.qual == NIL);
 843                                 foreach(l, splan->mergeplans)
 844                                 {
 845                                         lfirst(l) = set_plan_refs(root,
 846                                                                                           (Plan *) lfirst(l),
 847                                                                                           rtoffset);
 848                                 }
 849                         }
 850                         break;
 851                 case T_RecursiveUnion:
 852                         /* This doesn't evaluate targetlist or check quals either */
 853                         set_dummy_tlist_references(plan, rtoffset);
 854                         Assert(plan->qual == NIL);
 855                         break;
 856                 case T_BitmapAnd:
 857                         {
 858                                 BitmapAnd  *splan = (BitmapAnd *) plan;
 859
 860                                 /* BitmapAnd works like Append, but has no tlist */
 861                                 Assert(splan->plan.targetlist == NIL);
 862                                 Assert(splan->plan.qual == NIL);
 863                                 foreach(l, splan->bitmapplans)
 864                                 {
 865                                         lfirst(l) = set_plan_refs(root,
 866                                                                                           (Plan *) lfirst(l),
 867                                                                                           rtoffset);
 868                                 }
 869                         }
 870                         break;
 871                 case T_BitmapOr:
 872                         {
 873                                 BitmapOr   *splan = (BitmapOr *) plan;
 874
 875                                 /* BitmapOr works like Append, but has no tlist */
 876                                 Assert(splan->plan.targetlist == NIL);
 877                                 Assert(splan->plan.qual == NIL);
 878                                 foreach(l, splan->bitmapplans)
 879                                 {
 880                                         lfirst(l) = set_plan_refs(root,
 881                                                                                           (Plan *) lfirst(l),
 882                                                                                           rtoffset);
 883                                 }
 884                         }
 885                         break;
 886                 default:
 887                         elog(ERROR, "unrecognized node type: %d",
 888                                  (int) nodeTag(plan));
 889                         break;
 890         }
 891
 892         /*
 893          * Now recurse into child plans, if any
 894          *
 895          * NOTE: it is essential that we recurse into child plans AFTER we set
 896          * subplan references in this plan's tlist and quals.  If we did the
 897          * reference-adjustments bottom-up, then we would fail to match this
 898          * plan's var nodes against the already-modified nodes of the children.
 899          */
 900         plan->lefttree = set_plan_refs(root, plan->lefttree, rtoffset);
 901         plan->righttree = set_plan_refs(root, plan->righttree, rtoffset);
 902
 903         return plan;
 904 }
 905
 906 /*
 907  * set_indexonlyscan_references
 908  *              Do set_plan_references processing on an IndexOnlyScan
 909  *
 910  * This is unlike the handling of a plain IndexScan because we have to
 911  * convert Vars referencing the heap into Vars referencing the index.
 912  * We can use the fix_upper_expr machinery for that, by working from a
 913  * targetlist describing the index columns.
 914  */
 915 static Plan *
 916 set_indexonlyscan_references(PlannerInfo *root,
 917                                                          IndexOnlyScan *plan,
 918                                                          int rtoffset)
 919 {
 920         indexed_tlist *index_itlist;
 921
 922         index_itlist = build_tlist_index(plan->indextlist);
 923
 924         plan->scan.scanrelid += rtoffset;
 925         plan->scan.plan.targetlist = (List *)
 926                 fix_upper_expr(root,
 927                                            (Node *) plan->scan.plan.targetlist,
 928                                            index_itlist,
 929                                            INDEX_VAR,
 930                                            rtoffset);
 931         plan->scan.plan.qual = (List *)
 932                 fix_upper_expr(root,
 933                                            (Node *) plan->scan.plan.qual,
 934                                            index_itlist,
 935                                            INDEX_VAR,
 936                                            rtoffset);
 937         /* indexqual is already transformed to reference index columns */
 938         plan->indexqual = fix_scan_list(root, plan->indexqual, rtoffset);
 939         /* indexorderby is already transformed to reference index columns */
 940         plan->indexorderby = fix_scan_list(root, plan->indexorderby, rtoffset);
 941         /* indextlist must NOT be transformed to reference index columns */
 942         plan->indextlist = fix_scan_list(root, plan->indextlist, rtoffset);
 943
 944         pfree(index_itlist);
 945
 946         return (Plan *) plan;
 947 }
 948
 949 /*
 950  * set_subqueryscan_references
 951  *              Do set_plan_references processing on a SubqueryScan
 952  *
 953  * We try to strip out the SubqueryScan entirely; if we can't, we have
 954  * to do the normal processing on it.
 955  */
 956 static Plan *
 957 set_subqueryscan_references(PlannerInfo *root,
 958                                                         SubqueryScan *plan,
 959                                                         int rtoffset)
 960 {
 961         RelOptInfo *rel;
 962         Plan       *result;
 963
 964         /* Need to look up the subquery's RelOptInfo, since we need its subroot */
 965         rel = find_base_rel(root, plan->scan.scanrelid);
 966         Assert(rel->subplan == plan->subplan);
 967
 968         /* Recursively process the subplan */
 969         plan->subplan = set_plan_references(rel->subroot, plan->subplan);
 970
 971         if (trivial_subqueryscan(plan))
 972         {
 973                 /*
 974                  * We can omit the SubqueryScan node and just pull up the subplan.
 975                  */
 976                 ListCell   *lp,
 977                                    *lc;
 978
 979                 result = plan->subplan;
 980
 981                 /* We have to be sure we don't lose any initplans */
 982                 result->initPlan = list_concat(plan->scan.plan.initPlan,
 983                                                                            result->initPlan);
 984
 985                 /*
 986                  * We also have to transfer the SubqueryScan's result-column names
 987                  * into the subplan, else columns sent to client will be improperly
 988                  * labeled if this is the topmost plan level.  Copy the "source
 989                  * column" information too.
 990                  */
 991                 forboth(lp, plan->scan.plan.targetlist, lc, result->targetlist)
 992                 {
 993                         TargetEntry *ptle = (TargetEntry *) lfirst(lp);
 994                         TargetEntry *ctle = (TargetEntry *) lfirst(lc);
 995
 996                         ctle->resname = ptle->resname;
 997                         ctle->resorigtbl = ptle->resorigtbl;
 998                         ctle->resorigcol = ptle->resorigcol;
 999                 }
1000         }
1001         else
1002         {
1003                 /*
1004                  * Keep the SubqueryScan node.  We have to do the processing that
1005                  * set_plan_references would otherwise have done on it.  Notice we do
1006                  * not do set_upper_references() here, because a SubqueryScan will
1007                  * always have been created with correct references to its subplan's
1008                  * outputs to begin with.
1009                  */
1010                 plan->scan.scanrelid += rtoffset;
1011                 plan->scan.plan.targetlist =
1012                         fix_scan_list(root, plan->scan.plan.targetlist, rtoffset);
1013                 plan->scan.plan.qual =
1014                         fix_scan_list(root, plan->scan.plan.qual, rtoffset);
1015
1016                 result = (Plan *) plan;
1017         }
1018
1019         return result;
1020 }
1021
1022 /*
1023  * trivial_subqueryscan
1024  *              Detect whether a SubqueryScan can be deleted from the plan tree.
1025  *
1026  * We can delete it if it has no qual to check and the targetlist just
1027  * regurgitates the output of the child plan.
1028  */
1029 static bool
1030 trivial_subqueryscan(SubqueryScan *plan)
1031 {
1032         int                     attrno;
1033         ListCell   *lp,
1034                            *lc;
1035
1036         if (plan->scan.plan.qual != NIL)
1037                 return false;
1038
1039         if (list_length(plan->scan.plan.targetlist) !=
1040                 list_length(plan->subplan->targetlist))
1041                 return false;                   /* tlists not same length */
1042
1043         attrno = 1;
1044         forboth(lp, plan->scan.plan.targetlist, lc, plan->subplan->targetlist)
1045         {
1046                 TargetEntry *ptle = (TargetEntry *) lfirst(lp);
1047                 TargetEntry *ctle = (TargetEntry *) lfirst(lc);
1048
1049                 if (ptle->resjunk != ctle->resjunk)
1050                         return false;           /* tlist doesn't match junk status */
1051
1052                 /*
1053                  * We accept either a Var referencing the corresponding element of the
1054                  * subplan tlist, or a Const equaling the subplan element. See
1055                  * generate_setop_tlist() for motivation.
1056                  */
1057                 if (ptle->expr && IsA(ptle->expr, Var))
1058                 {
1059                         Var                *var = (Var *) ptle->expr;
1060
1061                         Assert(var->varno == plan->scan.scanrelid);
1062                         Assert(var->varlevelsup == 0);
1063                         if (var->varattno != attrno)
1064                                 return false;   /* out of order */
1065                 }
1066                 else if (ptle->expr && IsA(ptle->expr, Const))
1067                 {
1068                         if (!equal(ptle->expr, ctle->expr))
1069                                 return false;
1070                 }
1071                 else
1072                         return false;
1073
1074                 attrno++;
1075         }
1076
1077         return true;
1078 }
1079
1080 /*
1081  * set_foreignscan_references
1082  *         Do set_plan_references processing on a ForeignScan
1083  */
1084 static void
1085 set_foreignscan_references(PlannerInfo *root,
1086                                                    ForeignScan *fscan,
1087                                                    int rtoffset)
1088 {
1089         /* Adjust scanrelid if it's valid */
1090         if (fscan->scan.scanrelid > 0)
1091                 fscan->scan.scanrelid += rtoffset;
1092
1093         if (fscan->fdw_scan_tlist != NIL || fscan->scan.scanrelid == 0)
1094         {
1095                 /* Adjust tlist, qual, fdw_exprs to reference custom scan tuple */
1096                 indexed_tlist *itlist = build_tlist_index(fscan->fdw_scan_tlist);
1097
1098                 fscan->scan.plan.targetlist = (List *)
1099                         fix_upper_expr(root,
1100                                                    (Node *) fscan->scan.plan.targetlist,
1101                                                    itlist,
1102                                                    INDEX_VAR,
1103                                                    rtoffset);
1104                 fscan->scan.plan.qual = (List *)
1105                         fix_upper_expr(root,
1106                                                    (Node *) fscan->scan.plan.qual,
1107                                                    itlist,
1108                                                    INDEX_VAR,
1109                                                    rtoffset);
1110                 fscan->fdw_exprs = (List *)
1111                         fix_upper_expr(root,
1112                                                    (Node *) fscan->fdw_exprs,
1113                                                    itlist,
1114                                                    INDEX_VAR,
1115                                                    rtoffset);
1116                 pfree(itlist);
1117                 /* fdw_scan_tlist itself just needs fix_scan_list() adjustments */
1118                 fscan->fdw_scan_tlist =
1119                         fix_scan_list(root, fscan->fdw_scan_tlist, rtoffset);
1120         }
1121         else
1122         {
1123                 /* Adjust tlist, qual, fdw_exprs in the standard way */
1124                 fscan->scan.plan.targetlist =
1125                         fix_scan_list(root, fscan->scan.plan.targetlist, rtoffset);
1126                 fscan->scan.plan.qual =
1127                         fix_scan_list(root, fscan->scan.plan.qual, rtoffset);
1128                 fscan->fdw_exprs =
1129                         fix_scan_list(root, fscan->fdw_exprs, rtoffset);
1130         }
1131
1132         /* Adjust fs_relids if needed */
1133         if (rtoffset > 0)
1134         {
1135                 Bitmapset  *tempset = NULL;
1136                 int                     x = -1;
1137
1138                 while ((x = bms_next_member(fscan->fs_relids, x)) >= 0)
1139                         tempset = bms_add_member(tempset, x + rtoffset);
1140                 fscan->fs_relids = tempset;
1141         }
1142 }
1143
1144 /*
1145  * set_customscan_references
1146  *         Do set_plan_references processing on a CustomScan
1147  */
1148 static void
1149 set_customscan_references(PlannerInfo *root,
1150                                                   CustomScan *cscan,
1151                                                   int rtoffset)
1152 {
1153         /* Adjust scanrelid if it's valid */
1154         if (cscan->scan.scanrelid > 0)
1155                 cscan->scan.scanrelid += rtoffset;
1156
1157         if (cscan->custom_scan_tlist != NIL || cscan->scan.scanrelid == 0)
1158         {
1159                 /* Adjust tlist, qual, custom_exprs to reference custom scan tuple */
1160                 indexed_tlist *itlist = build_tlist_index(cscan->custom_scan_tlist);
1161
1162                 cscan->scan.plan.targetlist = (List *)
1163                         fix_upper_expr(root,
1164                                                    (Node *) cscan->scan.plan.targetlist,
1165                                                    itlist,
1166                                                    INDEX_VAR,
1167                                                    rtoffset);
1168                 cscan->scan.plan.qual = (List *)
1169                         fix_upper_expr(root,
1170                                                    (Node *) cscan->scan.plan.qual,
1171                                                    itlist,
1172                                                    INDEX_VAR,
1173                                                    rtoffset);
1174                 cscan->custom_exprs = (List *)
1175                         fix_upper_expr(root,
1176                                                    (Node *) cscan->custom_exprs,
1177                                                    itlist,
1178                                                    INDEX_VAR,
1179                                                    rtoffset);
1180                 pfree(itlist);
1181                 /* custom_scan_tlist itself just needs fix_scan_list() adjustments */
1182                 cscan->custom_scan_tlist =
1183                         fix_scan_list(root, cscan->custom_scan_tlist, rtoffset);
1184         }
1185         else
1186         {
1187                 /* Adjust tlist, qual, custom_exprs in the standard way */
1188                 cscan->scan.plan.targetlist =
1189                         fix_scan_list(root, cscan->scan.plan.targetlist, rtoffset);
1190                 cscan->scan.plan.qual =
1191                         fix_scan_list(root, cscan->scan.plan.qual, rtoffset);
1192                 cscan->custom_exprs =
1193                         fix_scan_list(root, cscan->custom_exprs, rtoffset);
1194         }
1195
1196         /* Adjust custom_relids if needed */
1197         if (rtoffset > 0)
1198         {
1199                 Bitmapset  *tempset = NULL;
1200                 int                     x = -1;
1201
1202                 while ((x = bms_next_member(cscan->custom_relids, x)) >= 0)
1203                         tempset = bms_add_member(tempset, x + rtoffset);
1204                 cscan->custom_relids = tempset;
1205         }
1206 }
1207
1208 /*
1209  * copyVar
1210  *              Copy a Var node.
1211  *
1212  * fix_scan_expr and friends do this enough times that it's worth having
1213  * a bespoke routine instead of using the generic copyObject() function.
1214  */
1215 static inline Var *
1216 copyVar(Var *var)
1217 {
1218         Var                *newvar = (Var *) palloc(sizeof(Var));
1219
1220         *newvar = *var;
1221         return newvar;
1222 }
1223
1224 /*
1225  * fix_expr_common
1226  *              Do generic set_plan_references processing on an expression node
1227  *
1228  * This is code that is common to all variants of expression-fixing.
1229  * We must look up operator opcode info for OpExpr and related nodes,
1230  * add OIDs from regclass Const nodes into root->glob->relationOids, and
1231  * add catalog TIDs for user-defined functions into root->glob->invalItems.
1232  *
1233  * We assume it's okay to update opcode info in-place.  So this could possibly
1234  * scribble on the planner's input data structures, but it's OK.
1235  */
1236 static void
1237 fix_expr_common(PlannerInfo *root, Node *node)
1238 {
1239         /* We assume callers won't call us on a NULL pointer */
1240         if (IsA(node, Aggref))
1241         {
1242                 record_plan_function_dependency(root,
1243                                                                                 ((Aggref *) node)->aggfnoid);
1244         }
1245         else if (IsA(node, WindowFunc))
1246         {
1247                 record_plan_function_dependency(root,
1248                                                                                 ((WindowFunc *) node)->winfnoid);
1249         }
1250         else if (IsA(node, FuncExpr))
1251         {
1252                 record_plan_function_dependency(root,
1253                                                                                 ((FuncExpr *) node)->funcid);
1254         }
1255         else if (IsA(node, OpExpr))
1256         {
1257                 set_opfuncid((OpExpr *) node);
1258                 record_plan_function_dependency(root,
1259                                                                                 ((OpExpr *) node)->opfuncid);
1260         }
1261         else if (IsA(node, DistinctExpr))
1262         {
1263                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1264                 record_plan_function_dependency(root,
1265                                                                                 ((DistinctExpr *) node)->opfuncid);
1266         }
1267         else if (IsA(node, NullIfExpr))
1268         {
1269                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1270                 record_plan_function_dependency(root,
1271                                                                                 ((NullIfExpr *) node)->opfuncid);
1272         }
1273         else if (IsA(node, ScalarArrayOpExpr))
1274         {
1275                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
1276                 record_plan_function_dependency(root,
1277                                                                          ((ScalarArrayOpExpr *) node)->opfuncid);
1278         }
1279         else if (IsA(node, ArrayCoerceExpr))
1280         {
1281                 if (OidIsValid(((ArrayCoerceExpr *) node)->elemfuncid))
1282                         record_plan_function_dependency(root,
1283                                                                          ((ArrayCoerceExpr *) node)->elemfuncid);
1284         }
1285         else if (IsA(node, Const))
1286         {
1287                 Const      *con = (Const *) node;
1288
1289                 /* Check for regclass reference */
1290                 if (ISREGCLASSCONST(con))
1291                         root->glob->relationOids =
1292                                 lappend_oid(root->glob->relationOids,
1293                                                         DatumGetObjectId(con->constvalue));
1294         }
1295 }
1296
1297 /*
1298  * fix_param_node
1299  *              Do set_plan_references processing on a Param
1300  *
1301  * If it's a PARAM_MULTIEXPR, replace it with the appropriate Param from
1302  * root->multiexpr_params; otherwise no change is needed.
1303  * Just for paranoia's sake, we make a copy of the node in either case.
1304  */
1305 static Node *
1306 fix_param_node(PlannerInfo *root, Param *p)
1307 {
1308         if (p->paramkind == PARAM_MULTIEXPR)
1309         {
1310                 int                     subqueryid = p->paramid >> 16;
1311                 int                     colno = p->paramid & 0xFFFF;
1312                 List       *params;
1313
1314                 if (subqueryid <= 0 ||
1315                         subqueryid > list_length(root->multiexpr_params))
1316                         elog(ERROR, "unexpected PARAM_MULTIEXPR ID: %d", p->paramid);
1317                 params = (List *) list_nth(root->multiexpr_params, subqueryid - 1);
1318                 if (colno <= 0 || colno > list_length(params))
1319                         elog(ERROR, "unexpected PARAM_MULTIEXPR ID: %d", p->paramid);
1320                 return copyObject(list_nth(params, colno - 1));
1321         }
1322         return copyObject(p);
1323 }
1324
1325 /*
1326  * fix_scan_expr
1327  *              Do set_plan_references processing on a scan-level expression
1328  *
1329  * This consists of incrementing all Vars' varnos by rtoffset,
1330  * replacing PARAM_MULTIEXPR Params, expanding PlaceHolderVars,
1331  * looking up operator opcode info for OpExpr and related nodes,
1332  * and adding OIDs from regclass Const nodes into root->glob->relationOids.
1333  */
1334 static Node *
1335 fix_scan_expr(PlannerInfo *root, Node *node, int rtoffset)
1336 {
1337         fix_scan_expr_context context;
1338
1339         context.root = root;
1340         context.rtoffset = rtoffset;
1341
1342         if (rtoffset != 0 ||
1343                 root->multiexpr_params != NIL ||
1344                 root->glob->lastPHId != 0)
1345         {
1346                 return fix_scan_expr_mutator(node, &context);
1347         }
1348         else
1349         {
1350                 /*
1351                  * If rtoffset == 0, we don't need to change any Vars, and if there
1352                  * are no MULTIEXPR subqueries then we don't need to replace
1353                  * PARAM_MULTIEXPR Params, and if there are no placeholders anywhere
1354                  * we won't need to remove them.  Then it's OK to just scribble on the
1355                  * input node tree instead of copying (since the only change, filling
1356                  * in any unset opfuncid fields, is harmless).  This saves just enough
1357                  * cycles to be noticeable on trivial queries.
1358                  */
1359                 (void) fix_scan_expr_walker(node, &context);
1360                 return node;
1361         }
1362 }
1363
1364 static Node *
1365 fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
1366 {
1367         if (node == NULL)
1368                 return NULL;
1369         if (IsA(node, Var))
1370         {
1371                 Var                *var = copyVar((Var *) node);
1372
1373                 Assert(var->varlevelsup == 0);
1374
1375                 /*
1376                  * We should not see any Vars marked INNER_VAR or OUTER_VAR.  But an
1377                  * indexqual expression could contain INDEX_VAR Vars.
1378                  */
1379                 Assert(var->varno != INNER_VAR);
1380                 Assert(var->varno != OUTER_VAR);
1381                 if (!IS_SPECIAL_VARNO(var->varno))
1382                         var->varno += context->rtoffset;
1383                 if (var->varnoold > 0)
1384                         var->varnoold += context->rtoffset;
1385                 return (Node *) var;
1386         }
1387         if (IsA(node, Param))
1388                 return fix_param_node(context->root, (Param *) node);
1389         if (IsA(node, CurrentOfExpr))
1390         {
1391                 CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);
1392
1393                 Assert(cexpr->cvarno != INNER_VAR);
1394                 Assert(cexpr->cvarno != OUTER_VAR);
1395                 if (!IS_SPECIAL_VARNO(cexpr->cvarno))
1396                         cexpr->cvarno += context->rtoffset;
1397                 return (Node *) cexpr;
1398         }
1399         if (IsA(node, PlaceHolderVar))
1400         {
1401                 /* At scan level, we should always just evaluate the contained expr */
1402                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
1403
1404                 return fix_scan_expr_mutator((Node *) phv->phexpr, context);
1405         }
1406         fix_expr_common(context->root, node);
1407         return expression_tree_mutator(node, fix_scan_expr_mutator,
1408                                                                    (void *) context);
1409 }
1410
1411 static bool
1412 fix_scan_expr_walker(Node *node, fix_scan_expr_context *context)
1413 {
1414         if (node == NULL)
1415                 return false;
1416         Assert(!IsA(node, PlaceHolderVar));
1417         fix_expr_common(context->root, node);
1418         return expression_tree_walker(node, fix_scan_expr_walker,
1419                                                                   (void *) context);
1420 }
1421
1422 /*
1423  * set_join_references
1424  *        Modify the target list and quals of a join node to reference its
1425  *        subplans, by setting the varnos to OUTER_VAR or INNER_VAR and setting
1426  *        attno values to the result domain number of either the corresponding
1427  *        outer or inner join tuple item.  Also perform opcode lookup for these
1428  *        expressions. and add regclass OIDs to root->glob->relationOids.
1429  */
1430 static void
1431 set_join_references(PlannerInfo *root, Join *join, int rtoffset)
1432 {
1433         Plan       *outer_plan = join->plan.lefttree;
1434         Plan       *inner_plan = join->plan.righttree;
1435         indexed_tlist *outer_itlist;
1436         indexed_tlist *inner_itlist;
1437
1438         outer_itlist = build_tlist_index(outer_plan->targetlist);
1439         inner_itlist = build_tlist_index(inner_plan->targetlist);
1440
1441         /*
1442          * First process the joinquals (including merge or hash clauses).  These
1443          * are logically below the join so they can always use all values
1444          * available from the input tlists.  It's okay to also handle
1445          * NestLoopParams now, because those couldn't refer to nullable
1446          * subexpressions.
1447          */
1448         join->joinqual = fix_join_expr(root,
1449                                                                    join->joinqual,
1450                                                                    outer_itlist,
1451                                                                    inner_itlist,
1452                                                                    (Index) 0,
1453                                                                    rtoffset);
1454
1455         /* Now do join-type-specific stuff */
1456         if (IsA(join, NestLoop))
1457         {
1458                 NestLoop   *nl = (NestLoop *) join;
1459                 ListCell   *lc;
1460
1461                 foreach(lc, nl->nestParams)
1462                 {
1463                         NestLoopParam *nlp = (NestLoopParam *) lfirst(lc);
1464
1465                         nlp->paramval = (Var *) fix_upper_expr(root,
1466                                                                                                    (Node *) nlp->paramval,
1467                                                                                                    outer_itlist,
1468                                                                                                    OUTER_VAR,
1469                                                                                                    rtoffset);
1470                         /* Check we replaced any PlaceHolderVar with simple Var */
1471                         if (!(IsA(nlp->paramval, Var) &&
1472                                   nlp->paramval->varno == OUTER_VAR))
1473                                 elog(ERROR, "NestLoopParam was not reduced to a simple Var");
1474                 }
1475         }
1476         else if (IsA(join, MergeJoin))
1477         {
1478                 MergeJoin  *mj = (MergeJoin *) join;
1479
1480                 mj->mergeclauses = fix_join_expr(root,
1481                                                                                  mj->mergeclauses,
1482                                                                                  outer_itlist,
1483                                                                                  inner_itlist,
1484                                                                                  (Index) 0,
1485                                                                                  rtoffset);
1486         }
1487         else if (IsA(join, HashJoin))
1488         {
1489                 HashJoin   *hj = (HashJoin *) join;
1490
1491                 hj->hashclauses = fix_join_expr(root,
1492                                                                                 hj->hashclauses,
1493                                                                                 outer_itlist,
1494                                                                                 inner_itlist,
1495                                                                                 (Index) 0,
1496                                                                                 rtoffset);
1497         }
1498
1499         /*
1500          * Now we need to fix up the targetlist and qpqual, which are logically
1501          * above the join.  This means they should not re-use any input expression
1502          * that was computed in the nullable side of an outer join.  Vars and
1503          * PlaceHolderVars are fine, so we can implement this restriction just by
1504          * clearing has_non_vars in the indexed_tlist structs.
1505          *
1506          * XXX This is a grotty workaround for the fact that we don't clearly
1507          * distinguish between a Var appearing below an outer join and the "same"
1508          * Var appearing above it.  If we did, we'd not need to hack the matching
1509          * rules this way.
1510          */
1511         switch (join->jointype)
1512         {
1513                 case JOIN_LEFT:
1514                 case JOIN_SEMI:
1515                 case JOIN_ANTI:
1516                         inner_itlist->has_non_vars = false;
1517                         break;
1518                 case JOIN_RIGHT:
1519                         outer_itlist->has_non_vars = false;
1520                         break;
1521                 case JOIN_FULL:
1522                         outer_itlist->has_non_vars = false;
1523                         inner_itlist->has_non_vars = false;
1524                         break;
1525                 default:
1526                         break;
1527         }
1528
1529         join->plan.targetlist = fix_join_expr(root,
1530                                                                                   join->plan.targetlist,
1531                                                                                   outer_itlist,
1532                                                                                   inner_itlist,
1533                                                                                   (Index) 0,
1534                                                                                   rtoffset);
1535         join->plan.qual = fix_join_expr(root,
1536                                                                         join->plan.qual,
1537                                                                         outer_itlist,
1538                                                                         inner_itlist,
1539                                                                         (Index) 0,
1540                                                                         rtoffset);
1541
1542         pfree(outer_itlist);
1543         pfree(inner_itlist);
1544 }
1545
1546 /*
1547  * set_upper_references
1548  *        Update the targetlist and quals of an upper-level plan node
1549  *        to refer to the tuples returned by its lefttree subplan.
1550  *        Also perform opcode lookup for these expressions, and
1551  *        add regclass OIDs to root->glob->relationOids.
1552  *
1553  * This is used for single-input plan types like Agg, Group, Result.
1554  *
1555  * In most cases, we have to match up individual Vars in the tlist and
1556  * qual expressions with elements of the subplan's tlist (which was
1557  * generated by flatten_tlist() from these selfsame expressions, so it
1558  * should have all the required variables).  There is an important exception,
1559  * however: GROUP BY and ORDER BY expressions will have been pushed into the
1560  * subplan tlist unflattened.  If these values are also needed in the output
1561  * then we want to reference the subplan tlist element rather than recomputing
1562  * the expression.
1563  */
1564 static void
1565 set_upper_references(PlannerInfo *root, Plan *plan, int rtoffset)
1566 {
1567         Plan       *subplan = plan->lefttree;
1568         indexed_tlist *subplan_itlist;
1569         List       *output_targetlist;
1570         ListCell   *l;
1571
1572         subplan_itlist = build_tlist_index(subplan->targetlist);
1573
1574         output_targetlist = NIL;
1575         foreach(l, plan->targetlist)
1576         {
1577                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1578                 Node       *newexpr;
1579
1580                 /* If it's a non-Var sort/group item, first try to match by sortref */
1581                 if (tle->ressortgroupref != 0 && !IsA(tle->expr, Var))
1582                 {
1583                         newexpr = (Node *)
1584                                 search_indexed_tlist_for_sortgroupref((Node *) tle->expr,
1585                                                                                                           tle->ressortgroupref,
1586                                                                                                           subplan_itlist,
1587                                                                                                           OUTER_VAR);
1588                         if (!newexpr)
1589                                 newexpr = fix_upper_expr(root,
1590                                                                                  (Node *) tle->expr,
1591                                                                                  subplan_itlist,
1592                                                                                  OUTER_VAR,
1593                                                                                  rtoffset);
1594                 }
1595                 else
1596                         newexpr = fix_upper_expr(root,
1597                                                                          (Node *) tle->expr,
1598                                                                          subplan_itlist,
1599                                                                          OUTER_VAR,
1600                                                                          rtoffset);
1601                 tle = flatCopyTargetEntry(tle);
1602                 tle->expr = (Expr *) newexpr;
1603                 output_targetlist = lappend(output_targetlist, tle);
1604         }
1605         plan->targetlist = output_targetlist;
1606
1607         plan->qual = (List *)
1608                 fix_upper_expr(root,
1609                                            (Node *) plan->qual,
1610                                            subplan_itlist,
1611                                            OUTER_VAR,
1612                                            rtoffset);
1613
1614         pfree(subplan_itlist);
1615 }
1616
1617 /*
1618  * set_dummy_tlist_references
1619  *        Replace the targetlist of an upper-level plan node with a simple
1620  *        list of OUTER_VAR references to its child.
1621  *
1622  * This is used for plan types like Sort and Append that don't evaluate
1623  * their targetlists.  Although the executor doesn't care at all what's in
1624  * the tlist, EXPLAIN needs it to be realistic.
1625  *
1626  * Note: we could almost use set_upper_references() here, but it fails for
1627  * Append for lack of a lefttree subplan.  Single-purpose code is faster
1628  * anyway.
1629  */
1630 static void
1631 set_dummy_tlist_references(Plan *plan, int rtoffset)
1632 {
1633         List       *output_targetlist;
1634         ListCell   *l;
1635
1636         output_targetlist = NIL;
1637         foreach(l, plan->targetlist)
1638         {
1639                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1640                 Var                *oldvar = (Var *) tle->expr;
1641                 Var                *newvar;
1642
1643                 newvar = makeVar(OUTER_VAR,
1644                                                  tle->resno,
1645                                                  exprType((Node *) oldvar),
1646                                                  exprTypmod((Node *) oldvar),
1647                                                  exprCollation((Node *) oldvar),
1648                                                  0);
1649                 if (IsA(oldvar, Var))
1650                 {
1651                         newvar->varnoold = oldvar->varno + rtoffset;
1652                         newvar->varoattno = oldvar->varattno;
1653                 }
1654                 else
1655                 {
1656                         newvar->varnoold = 0;           /* wasn't ever a plain Var */
1657                         newvar->varoattno = 0;
1658                 }
1659
1660                 tle = flatCopyTargetEntry(tle);
1661                 tle->expr = (Expr *) newvar;
1662                 output_targetlist = lappend(output_targetlist, tle);
1663         }
1664         plan->targetlist = output_targetlist;
1665
1666         /* We don't touch plan->qual here */
1667 }
1668
1669
1670 /*
1671  * build_tlist_index --- build an index data structure for a child tlist
1672  *
1673  * In most cases, subplan tlists will be "flat" tlists with only Vars,
1674  * so we try to optimize that case by extracting information about Vars
1675  * in advance.  Matching a parent tlist to a child is still an O(N^2)
1676  * operation, but at least with a much smaller constant factor than plain
1677  * tlist_member() searches.
1678  *
1679  * The result of this function is an indexed_tlist struct to pass to
1680  * search_indexed_tlist_for_var() or search_indexed_tlist_for_non_var().
1681  * When done, the indexed_tlist may be freed with a single pfree().
1682  */
1683 static indexed_tlist *
1684 build_tlist_index(List *tlist)
1685 {
1686         indexed_tlist *itlist;
1687         tlist_vinfo *vinfo;
1688         ListCell   *l;
1689
1690         /* Create data structure with enough slots for all tlist entries */
1691         itlist = (indexed_tlist *)
1692                 palloc(offsetof(indexed_tlist, vars) +
1693                            list_length(tlist) * sizeof(tlist_vinfo));
1694
1695         itlist->tlist = tlist;
1696         itlist->has_ph_vars = false;
1697         itlist->has_non_vars = false;
1698
1699         /* Find the Vars and fill in the index array */
1700         vinfo = itlist->vars;
1701         foreach(l, tlist)
1702         {
1703                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1704
1705                 if (tle->expr && IsA(tle->expr, Var))
1706                 {
1707                         Var                *var = (Var *) tle->expr;
1708
1709                         vinfo->varno = var->varno;
1710                         vinfo->varattno = var->varattno;
1711                         vinfo->resno = tle->resno;
1712                         vinfo++;
1713                 }
1714                 else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
1715                         itlist->has_ph_vars = true;
1716                 else
1717                         itlist->has_non_vars = true;
1718         }
1719
1720         itlist->num_vars = (vinfo - itlist->vars);
1721
1722         return itlist;
1723 }
1724
1725 /*
1726  * build_tlist_index_other_vars --- build a restricted tlist index
1727  *
1728  * This is like build_tlist_index, but we only index tlist entries that
1729  * are Vars belonging to some rel other than the one specified.  We will set
1730  * has_ph_vars (allowing PlaceHolderVars to be matched), but not has_non_vars
1731  * (so nothing other than Vars and PlaceHolderVars can be matched).
1732  */
1733 static indexed_tlist *
1734 build_tlist_index_other_vars(List *tlist, Index ignore_rel)
1735 {
1736         indexed_tlist *itlist;
1737         tlist_vinfo *vinfo;
1738         ListCell   *l;
1739
1740         /* Create data structure with enough slots for all tlist entries */
1741         itlist = (indexed_tlist *)
1742                 palloc(offsetof(indexed_tlist, vars) +
1743                            list_length(tlist) * sizeof(tlist_vinfo));
1744
1745         itlist->tlist = tlist;
1746         itlist->has_ph_vars = false;
1747         itlist->has_non_vars = false;
1748
1749         /* Find the desired Vars and fill in the index array */
1750         vinfo = itlist->vars;
1751         foreach(l, tlist)
1752         {
1753                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1754
1755                 if (tle->expr && IsA(tle->expr, Var))
1756                 {
1757                         Var                *var = (Var *) tle->expr;
1758
1759                         if (var->varno != ignore_rel)
1760                         {
1761                                 vinfo->varno = var->varno;
1762                                 vinfo->varattno = var->varattno;
1763                                 vinfo->resno = tle->resno;
1764                                 vinfo++;
1765                         }
1766                 }
1767                 else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
1768                         itlist->has_ph_vars = true;
1769         }
1770
1771         itlist->num_vars = (vinfo - itlist->vars);
1772
1773         return itlist;
1774 }
1775
1776 /*
1777  * search_indexed_tlist_for_var --- find a Var in an indexed tlist
1778  *
1779  * If a match is found, return a copy of the given Var with suitably
1780  * modified varno/varattno (to wit, newvarno and the resno of the TLE entry).
1781  * Also ensure that varnoold is incremented by rtoffset.
1782  * If no match, return NULL.
1783  */
1784 static Var *
1785 search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
1786                                                          Index newvarno, int rtoffset)
1787 {
1788         Index           varno = var->varno;
1789         AttrNumber      varattno = var->varattno;
1790         tlist_vinfo *vinfo;
1791         int                     i;
1792
1793         vinfo = itlist->vars;
1794         i = itlist->num_vars;
1795         while (i-- > 0)
1796         {
1797                 if (vinfo->varno == varno && vinfo->varattno == varattno)
1798                 {
1799                         /* Found a match */
1800                         Var                *newvar = copyVar(var);
1801
1802                         newvar->varno = newvarno;
1803                         newvar->varattno = vinfo->resno;
1804                         if (newvar->varnoold > 0)
1805                                 newvar->varnoold += rtoffset;
1806                         return newvar;
1807                 }
1808                 vinfo++;
1809         }
1810         return NULL;                            /* no match */
1811 }
1812
1813 /*
1814  * search_indexed_tlist_for_non_var --- find a non-Var in an indexed tlist
1815  *
1816  * If a match is found, return a Var constructed to reference the tlist item.
1817  * If no match, return NULL.
1818  *
1819  * NOTE: it is a waste of time to call this unless itlist->has_ph_vars or
1820  * itlist->has_non_vars.  Furthermore, set_join_references() relies on being
1821  * able to prevent matching of non-Vars by clearing itlist->has_non_vars,
1822  * so there's a correctness reason not to call it unless that's set.
1823  */
1824 static Var *
1825 search_indexed_tlist_for_non_var(Node *node,
1826                                                                  indexed_tlist *itlist, Index newvarno)
1827 {
1828         TargetEntry *tle;
1829
1830         tle = tlist_member(node, itlist->tlist);
1831         if (tle)
1832         {
1833                 /* Found a matching subplan output expression */
1834                 Var                *newvar;
1835
1836                 newvar = makeVarFromTargetEntry(newvarno, tle);
1837                 newvar->varnoold = 0;   /* wasn't ever a plain Var */
1838                 newvar->varoattno = 0;
1839                 return newvar;
1840         }
1841         return NULL;                            /* no match */
1842 }
1843
1844 /*
1845  * search_indexed_tlist_for_sortgroupref --- find a sort/group expression
1846  *              (which is assumed not to be just a Var)
1847  *
1848  * If a match is found, return a Var constructed to reference the tlist item.
1849  * If no match, return NULL.
1850  *
1851  * This is needed to ensure that we select the right subplan TLE in cases
1852  * where there are multiple textually-equal()-but-volatile sort expressions.
1853  * And it's also faster than search_indexed_tlist_for_non_var.
1854  */
1855 static Var *
1856 search_indexed_tlist_for_sortgroupref(Node *node,
1857                                                                           Index sortgroupref,
1858                                                                           indexed_tlist *itlist,
1859                                                                           Index newvarno)
1860 {
1861         ListCell   *lc;
1862
1863         foreach(lc, itlist->tlist)
1864         {
1865                 TargetEntry *tle = (TargetEntry *) lfirst(lc);
1866
1867                 /* The equal() check should be redundant, but let's be paranoid */
1868                 if (tle->ressortgroupref == sortgroupref &&
1869                         equal(node, tle->expr))
1870                 {
1871                         /* Found a matching subplan output expression */
1872                         Var                *newvar;
1873
1874                         newvar = makeVarFromTargetEntry(newvarno, tle);
1875                         newvar->varnoold = 0;           /* wasn't ever a plain Var */
1876                         newvar->varoattno = 0;
1877                         return newvar;
1878                 }
1879         }
1880         return NULL;                            /* no match */
1881 }
1882
1883 /*
1884  * fix_join_expr
1885  *         Create a new set of targetlist entries or join qual clauses by
1886  *         changing the varno/varattno values of variables in the clauses
1887  *         to reference target list values from the outer and inner join
1888  *         relation target lists.  Also perform opcode lookup and add
1889  *         regclass OIDs to root->glob->relationOids.
1890  *
1891  * This is used in two different scenarios: a normal join clause, where all
1892  * the Vars in the clause *must* be replaced by OUTER_VAR or INNER_VAR
1893  * references; and a RETURNING clause, which may contain both Vars of the
1894  * target relation and Vars of other relations.  In the latter case we want
1895  * to replace the other-relation Vars by OUTER_VAR references, while leaving
1896  * target Vars alone.
1897  *
1898  * For a normal join, acceptable_rel should be zero so that any failure to
1899  * match a Var will be reported as an error.  For the RETURNING case, pass
1900  * inner_itlist = NULL and acceptable_rel = the ID of the target relation.
1901  *
1902  * 'clauses' is the targetlist or list of join clauses
1903  * 'outer_itlist' is the indexed target list of the outer join relation,
1904  *              or NULL
1905  * 'inner_itlist' is the indexed target list of the inner join relation,
1906  *              or NULL
1907  * 'acceptable_rel' is either zero or the rangetable index of a relation
1908  *              whose Vars may appear in the clause without provoking an error
1909  * 'rtoffset': how much to increment varnoold by
1910  *
1911  * Returns the new expression tree.  The original clause structure is
1912  * not modified.
1913  */
1914 static List *
1915 fix_join_expr(PlannerInfo *root,
1916                           List *clauses,
1917                           indexed_tlist *outer_itlist,
1918                           indexed_tlist *inner_itlist,
1919                           Index acceptable_rel,
1920                           int rtoffset)
1921 {
1922         fix_join_expr_context context;
1923
1924         context.root = root;
1925         context.outer_itlist = outer_itlist;
1926         context.inner_itlist = inner_itlist;
1927         context.acceptable_rel = acceptable_rel;
1928         context.rtoffset = rtoffset;
1929         return (List *) fix_join_expr_mutator((Node *) clauses, &context);
1930 }
1931
1932 static Node *
1933 fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
1934 {
1935         Var                *newvar;
1936
1937         if (node == NULL)
1938                 return NULL;
1939         if (IsA(node, Var))
1940         {
1941                 Var                *var = (Var *) node;
1942
1943                 /* First look for the var in the input tlists */
1944                 if (context->outer_itlist)
1945                 {
1946                         newvar = search_indexed_tlist_for_var(var,
1947                                                                                                   context->outer_itlist,
1948                                                                                                   OUTER_VAR,
1949                                                                                                   context->rtoffset);
1950                         if (newvar)
1951                                 return (Node *) newvar;
1952                 }
1953
1954                 /* Then in the outer */
1955                 if (context->inner_itlist)
1956                 {
1957                         newvar = search_indexed_tlist_for_var(var,
1958                                                                                                   context->inner_itlist,
1959                                                                                                   INNER_VAR,
1960                                                                                                   context->rtoffset);
1961                         if (newvar)
1962                                 return (Node *) newvar;
1963                 }
1964
1965                 /* If it's for acceptable_rel, adjust and return it */
1966                 if (var->varno == context->acceptable_rel)
1967                 {
1968                         var = copyVar(var);
1969                         var->varno += context->rtoffset;
1970                         if (var->varnoold > 0)
1971                                 var->varnoold += context->rtoffset;
1972                         return (Node *) var;
1973                 }
1974
1975                 /* No referent found for Var */
1976                 elog(ERROR, "variable not found in subplan target lists");
1977         }
1978         if (IsA(node, PlaceHolderVar))
1979         {
1980                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
1981
1982                 /* See if the PlaceHolderVar has bubbled up from a lower plan node */
1983                 if (context->outer_itlist && context->outer_itlist->has_ph_vars)
1984                 {
1985                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1986                                                                                                           context->outer_itlist,
1987                                                                                                           OUTER_VAR);
1988                         if (newvar)
1989                                 return (Node *) newvar;
1990                 }
1991                 if (context->inner_itlist && context->inner_itlist->has_ph_vars)
1992                 {
1993                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1994                                                                                                           context->inner_itlist,
1995                                                                                                           INNER_VAR);
1996                         if (newvar)
1997                                 return (Node *) newvar;
1998                 }
1999
2000                 /* If not supplied by input plans, evaluate the contained expr */
2001                 return fix_join_expr_mutator((Node *) phv->phexpr, context);
2002         }
2003         if (IsA(node, Param))
2004                 return fix_param_node(context->root, (Param *) node);
2005         /* Try matching more complex expressions too, if tlists have any */
2006         if (context->outer_itlist && context->outer_itlist->has_non_vars)
2007         {
2008                 newvar = search_indexed_tlist_for_non_var(node,
2009                                                                                                   context->outer_itlist,
2010                                                                                                   OUTER_VAR);
2011                 if (newvar)
2012                         return (Node *) newvar;
2013         }
2014         if (context->inner_itlist && context->inner_itlist->has_non_vars)
2015         {
2016                 newvar = search_indexed_tlist_for_non_var(node,
2017                                                                                                   context->inner_itlist,
2018                                                                                                   INNER_VAR);
2019                 if (newvar)
2020                         return (Node *) newvar;
2021         }
2022         fix_expr_common(context->root, node);
2023         return expression_tree_mutator(node,
2024                                                                    fix_join_expr_mutator,
2025                                                                    (void *) context);
2026 }
2027
2028 /*
2029  * fix_upper_expr
2030  *              Modifies an expression tree so that all Var nodes reference outputs
2031  *              of a subplan.  Also performs opcode lookup, and adds regclass OIDs to
2032  *              root->glob->relationOids.
2033  *
2034  * This is used to fix up target and qual expressions of non-join upper-level
2035  * plan nodes, as well as index-only scan nodes.
2036  *
2037  * An error is raised if no matching var can be found in the subplan tlist
2038  * --- so this routine should only be applied to nodes whose subplans'
2039  * targetlists were generated via flatten_tlist() or some such method.
2040  *
2041  * If itlist->has_non_vars is true, then we try to match whole subexpressions
2042  * against elements of the subplan tlist, so that we can avoid recomputing
2043  * expressions that were already computed by the subplan.  (This is relatively
2044  * expensive, so we don't want to try it in the common case where the
2045  * subplan tlist is just a flattened list of Vars.)
2046  *
2047  * 'node': the tree to be fixed (a target item or qual)
2048  * 'subplan_itlist': indexed target list for subplan (or index)
2049  * 'newvarno': varno to use for Vars referencing tlist elements
2050  * 'rtoffset': how much to increment varnoold by
2051  *
2052  * The resulting tree is a copy of the original in which all Var nodes have
2053  * varno = newvarno, varattno = resno of corresponding targetlist element.
2054  * The original tree is not modified.
2055  */
2056 static Node *
2057 fix_upper_expr(PlannerInfo *root,
2058                            Node *node,
2059                            indexed_tlist *subplan_itlist,
2060                            Index newvarno,
2061                            int rtoffset)
2062 {
2063         fix_upper_expr_context context;
2064
2065         context.root = root;
2066         context.subplan_itlist = subplan_itlist;
2067         context.newvarno = newvarno;
2068         context.rtoffset = rtoffset;
2069         return fix_upper_expr_mutator(node, &context);
2070 }
2071
2072 static Node *
2073 fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
2074 {
2075         Var                *newvar;
2076
2077         if (node == NULL)
2078                 return NULL;
2079         if (IsA(node, Var))
2080         {
2081                 Var                *var = (Var *) node;
2082
2083                 newvar = search_indexed_tlist_for_var(var,
2084                                                                                           context->subplan_itlist,
2085                                                                                           context->newvarno,
2086                                                                                           context->rtoffset);
2087                 if (!newvar)
2088                         elog(ERROR, "variable not found in subplan target list");
2089                 return (Node *) newvar;
2090         }
2091         if (IsA(node, PlaceHolderVar))
2092         {
2093                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
2094
2095                 /* See if the PlaceHolderVar has bubbled up from a lower plan node */
2096                 if (context->subplan_itlist->has_ph_vars)
2097                 {
2098                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
2099                                                                                                           context->subplan_itlist,
2100                                                                                                           context->newvarno);
2101                         if (newvar)
2102                                 return (Node *) newvar;
2103                 }
2104                 /* If not supplied by input plan, evaluate the contained expr */
2105                 return fix_upper_expr_mutator((Node *) phv->phexpr, context);
2106         }
2107         if (IsA(node, Param))
2108                 return fix_param_node(context->root, (Param *) node);
2109         /* Try matching more complex expressions too, if tlist has any */
2110         if (context->subplan_itlist->has_non_vars)
2111         {
2112                 newvar = search_indexed_tlist_for_non_var(node,
2113                                                                                                   context->subplan_itlist,
2114                                                                                                   context->newvarno);
2115                 if (newvar)
2116                         return (Node *) newvar;
2117         }
2118         fix_expr_common(context->root, node);
2119         return expression_tree_mutator(node,
2120                                                                    fix_upper_expr_mutator,
2121                                                                    (void *) context);
2122 }
2123
2124 /*
2125  * set_returning_clause_references
2126  *              Perform setrefs.c's work on a RETURNING targetlist
2127  *
2128  * If the query involves more than just the result table, we have to
2129  * adjust any Vars that refer to other tables to reference junk tlist
2130  * entries in the top subplan's targetlist.  Vars referencing the result
2131  * table should be left alone, however (the executor will evaluate them
2132  * using the actual heap tuple, after firing triggers if any).  In the
2133  * adjusted RETURNING list, result-table Vars will have their original
2134  * varno (plus rtoffset), but Vars for other rels will have varno OUTER_VAR.
2135  *
2136  * We also must perform opcode lookup and add regclass OIDs to
2137  * root->glob->relationOids.
2138  *
2139  * 'rlist': the RETURNING targetlist to be fixed
2140  * 'topplan': the top subplan node that will be just below the ModifyTable
2141  *              node (note it's not yet passed through set_plan_refs)
2142  * 'resultRelation': RT index of the associated result relation
2143  * 'rtoffset': how much to increment varnos by
2144  *
2145  * Note: the given 'root' is for the parent query level, not the 'topplan'.
2146  * This does not matter currently since we only access the dependency-item
2147  * lists in root->glob, but it would need some hacking if we wanted a root
2148  * that actually matches the subplan.
2149  *
2150  * Note: resultRelation is not yet adjusted by rtoffset.
2151  */
2152 static List *
2153 set_returning_clause_references(PlannerInfo *root,
2154                                                                 List *rlist,
2155                                                                 Plan *topplan,
2156                                                                 Index resultRelation,
2157                                                                 int rtoffset)
2158 {
2159         indexed_tlist *itlist;
2160
2161         /*
2162          * We can perform the desired Var fixup by abusing the fix_join_expr
2163          * machinery that formerly handled inner indexscan fixup.  We search the
2164          * top plan's targetlist for Vars of non-result relations, and use
2165          * fix_join_expr to convert RETURNING Vars into references to those tlist
2166          * entries, while leaving result-rel Vars as-is.
2167          *
2168          * PlaceHolderVars will also be sought in the targetlist, but no
2169          * more-complex expressions will be.  Note that it is not possible for a
2170          * PlaceHolderVar to refer to the result relation, since the result is
2171          * never below an outer join.  If that case could happen, we'd have to be
2172          * prepared to pick apart the PlaceHolderVar and evaluate its contained
2173          * expression instead.
2174          */
2175         itlist = build_tlist_index_other_vars(topplan->targetlist, resultRelation);
2176
2177         rlist = fix_join_expr(root,
2178                                                   rlist,
2179                                                   itlist,
2180                                                   NULL,
2181                                                   resultRelation,
2182                                                   rtoffset);
2183
2184         pfree(itlist);
2185
2186         return rlist;
2187 }
2188
2189 /*****************************************************************************
2190  *                                      OPERATOR REGPROC LOOKUP
2191  *****************************************************************************/
2192
2193 /*
2194  * fix_opfuncids
2195  *        Calculate opfuncid field from opno for each OpExpr node in given tree.
2196  *        The given tree can be anything expression_tree_walker handles.
2197  *
2198  * The argument is modified in-place.  (This is OK since we'd want the
2199  * same change for any node, even if it gets visited more than once due to
2200  * shared structure.)
2201  */
2202 void
2203 fix_opfuncids(Node *node)
2204 {
2205         /* This tree walk requires no special setup, so away we go... */
2206         fix_opfuncids_walker(node, NULL);
2207 }
2208
2209 static bool
2210 fix_opfuncids_walker(Node *node, void *context)
2211 {
2212         if (node == NULL)
2213                 return false;
2214         if (IsA(node, OpExpr))
2215                 set_opfuncid((OpExpr *) node);
2216         else if (IsA(node, DistinctExpr))
2217                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
2218         else if (IsA(node, NullIfExpr))
2219                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
2220         else if (IsA(node, ScalarArrayOpExpr))
2221                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
2222         return expression_tree_walker(node, fix_opfuncids_walker, context);
2223 }
2224
2225 /*
2226  * set_opfuncid
2227  *              Set the opfuncid (procedure OID) in an OpExpr node,
2228  *              if it hasn't been set already.
2229  *
2230  * Because of struct equivalence, this can also be used for
2231  * DistinctExpr and NullIfExpr nodes.
2232  */
2233 void
2234 set_opfuncid(OpExpr *opexpr)
2235 {
2236         if (opexpr->opfuncid == InvalidOid)
2237                 opexpr->opfuncid = get_opcode(opexpr->opno);
2238 }
2239
2240 /*
2241  * set_sa_opfuncid
2242  *              As above, for ScalarArrayOpExpr nodes.
2243  */
2244 void
2245 set_sa_opfuncid(ScalarArrayOpExpr *opexpr)
2246 {
2247         if (opexpr->opfuncid == InvalidOid)
2248                 opexpr->opfuncid = get_opcode(opexpr->opno);
2249 }
2250
2251 /*****************************************************************************
2252  *                                      QUERY DEPENDENCY MANAGEMENT
2253  *****************************************************************************/
2254
2255 /*
2256  * record_plan_function_dependency
2257  *              Mark the current plan as depending on a particular function.
2258  *
2259  * This is exported so that the function-inlining code can record a
2260  * dependency on a function that it's removed from the plan tree.
2261  */
2262 void
2263 record_plan_function_dependency(PlannerInfo *root, Oid funcid)
2264 {
2265         /*
2266          * For performance reasons, we don't bother to track built-in functions;
2267          * we just assume they'll never change (or at least not in ways that'd
2268          * invalidate plans using them).  For this purpose we can consider a
2269          * built-in function to be one with OID less than FirstBootstrapObjectId.
2270          * Note that the OID generator guarantees never to generate such an OID
2271          * after startup, even at OID wraparound.
2272          */
2273         if (funcid >= (Oid) FirstBootstrapObjectId)
2274         {
2275                 PlanInvalItem *inval_item = makeNode(PlanInvalItem);
2276
2277                 /*
2278                  * It would work to use any syscache on pg_proc, but the easiest is
2279                  * PROCOID since we already have the function's OID at hand.  Note
2280                  * that plancache.c knows we use PROCOID.
2281                  */
2282                 inval_item->cacheId = PROCOID;
2283                 inval_item->hashValue = GetSysCacheHashValue1(PROCOID,
2284                                                                                                    ObjectIdGetDatum(funcid));
2285
2286                 root->glob->invalItems = lappend(root->glob->invalItems, inval_item);
2287         }
2288 }
2289
2290 /*
2291  * extract_query_dependencies
2292  *              Given a not-yet-planned query or queries (i.e. a Query node or list
2293  *              of Query nodes), extract dependencies just as set_plan_references
2294  *              would do.
2295  *
2296  * This is needed by plancache.c to handle invalidation of cached unplanned
2297  * queries.
2298  */
2299 void
2300 extract_query_dependencies(Node *query,
2301                                                    List **relationOids,
2302                                                    List **invalItems,
2303                                                    bool *hasRowSecurity)
2304 {
2305         PlannerGlobal glob;
2306         PlannerInfo root;
2307
2308         /* Make up dummy planner state so we can use this module's machinery */
2309         MemSet(&glob, 0, sizeof(glob));
2310         glob.type = T_PlannerGlobal;
2311         glob.relationOids = NIL;
2312         glob.invalItems = NIL;
2313         glob.hasRowSecurity = false;
2314
2315         MemSet(&root, 0, sizeof(root));
2316         root.type = T_PlannerInfo;
2317         root.glob = &glob;
2318
2319         (void) extract_query_dependencies_walker(query, &root);
2320
2321         *relationOids = glob.relationOids;
2322         *invalItems = glob.invalItems;
2323         *hasRowSecurity = glob.hasRowSecurity;
2324 }
2325
2326 static bool
2327 extract_query_dependencies_walker(Node *node, PlannerInfo *context)
2328 {
2329         if (node == NULL)
2330                 return false;
2331         Assert(!IsA(node, PlaceHolderVar));
2332         /* Extract function dependencies and check for regclass Consts */
2333         fix_expr_common(context, node);
2334         if (IsA(node, Query))
2335         {
2336                 Query      *query = (Query *) node;
2337                 ListCell   *lc;
2338
2339                 /* Collect row security information */
2340                 context->glob->hasRowSecurity = query->hasRowSecurity;
2341
2342                 if (query->commandType == CMD_UTILITY)
2343                 {
2344                         /*
2345                          * Ignore utility statements, except those (such as EXPLAIN) that
2346                          * contain a parsed-but-not-planned query.
2347                          */
2348                         query = UtilityContainsQuery(query->utilityStmt);
2349                         if (query == NULL)
2350                                 return false;
2351                 }
2352
2353                 /* Collect relation OIDs in this Query's rtable */
2354                 foreach(lc, query->rtable)
2355                 {
2356                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
2357
2358                         if (rte->rtekind == RTE_RELATION)
2359                                 context->glob->relationOids =
2360                                         lappend_oid(context->glob->relationOids, rte->relid);
2361                 }
2362
2363                 /* And recurse into the query's subexpressions */
2364                 return query_tree_walker(query, extract_query_dependencies_walker,
2365                                                                  (void *) context, 0);
2366         }
2367         return expression_tree_walker(node, extract_query_dependencies_walker,
2368                                                                   (void *) context);
2369 }