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