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) 1996-2008, PostgreSQL Global Development Group
   8  * Portions Copyright (c) 1994, Regents of the University of California
   9  *
  10  *
  11  * IDENTIFICATION
  12  *        $PostgreSQL: pgsql/src/backend/optimizer/plan/setrefs.c,v 1.146 2008/10/21 20:42:53 tgl Exp $
  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/clauses.h"
  23 #include "optimizer/planmain.h"
  24 #include "optimizer/tlist.h"
  25 #include "parser/parsetree.h"
  26 #include "utils/lsyscache.h"
  27 #include "utils/syscache.h"
  28
  29
  30 typedef struct
  31 {
  32         Index           varno;                  /* RT index of Var */
  33         AttrNumber      varattno;               /* attr number of Var */
  34         AttrNumber      resno;                  /* TLE position of Var */
  35 } tlist_vinfo;
  36
  37 typedef struct
  38 {
  39         List       *tlist;                      /* underlying target list */
  40         int                     num_vars;               /* number of plain Var tlist entries */
  41         bool            has_ph_vars;    /* are there PlaceHolderVar entries? */
  42         bool            has_non_vars;   /* are there other entries? */
  43         /* array of num_vars entries: */
  44         tlist_vinfo vars[1];            /* VARIABLE LENGTH ARRAY */
  45 } indexed_tlist;                                /* VARIABLE LENGTH STRUCT */
  46
  47 typedef struct
  48 {
  49         PlannerGlobal *glob;
  50         int                     rtoffset;
  51 } fix_scan_expr_context;
  52
  53 typedef struct
  54 {
  55         PlannerGlobal *glob;
  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         PlannerGlobal *glob;
  65         indexed_tlist *subplan_itlist;
  66         int                     rtoffset;
  67 } fix_upper_expr_context;
  68
  69 /*
  70  * Check if a Const node is a regclass value.  We accept plain OID too,
  71  * since a regclass Const will get folded to that type if it's an argument
  72  * to oideq or similar operators.  (This might result in some extraneous
  73  * values in a plan's list of relation dependencies, but the worst result
  74  * would be occasional useless replans.)
  75  */
  76 #define ISREGCLASSCONST(con) \
  77         (((con)->consttype == REGCLASSOID || (con)->consttype == OIDOID) && \
  78          !(con)->constisnull)
  79
  80 #define fix_scan_list(glob, lst, rtoffset) \
  81         ((List *) fix_scan_expr(glob, (Node *) (lst), rtoffset))
  82
  83 static Plan *set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset);
  84 static Plan *set_subqueryscan_references(PlannerGlobal *glob,
  85                                                         SubqueryScan *plan,
  86                                                         int rtoffset);
  87 static bool trivial_subqueryscan(SubqueryScan *plan);
  88 static Node *fix_scan_expr(PlannerGlobal *glob, Node *node, int rtoffset);
  89 static Node *fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context);
  90 static bool fix_scan_expr_walker(Node *node, fix_scan_expr_context *context);
  91 static void set_join_references(PlannerGlobal *glob, Join *join, int rtoffset);
  92 static void set_inner_join_references(PlannerGlobal *glob, Plan *inner_plan,
  93                                                   indexed_tlist *outer_itlist);
  94 static void set_upper_references(PlannerGlobal *glob, Plan *plan, int rtoffset);
  95 static void set_dummy_tlist_references(Plan *plan, int rtoffset);
  96 static indexed_tlist *build_tlist_index(List *tlist);
  97 static Var *search_indexed_tlist_for_var(Var *var,
  98                                                          indexed_tlist *itlist,
  99                                                          Index newvarno,
 100                                                          int rtoffset);
 101 static Var *search_indexed_tlist_for_non_var(Node *node,
 102                                                                  indexed_tlist *itlist,
 103                                                                  Index newvarno);
 104 static List *fix_join_expr(PlannerGlobal *glob,
 105                           List *clauses,
 106                           indexed_tlist *outer_itlist,
 107                           indexed_tlist *inner_itlist,
 108                           Index acceptable_rel, int rtoffset);
 109 static Node *fix_join_expr_mutator(Node *node,
 110                                           fix_join_expr_context *context);
 111 static Node *fix_upper_expr(PlannerGlobal *glob,
 112                            Node *node,
 113                            indexed_tlist *subplan_itlist,
 114                            int rtoffset);
 115 static Node *fix_upper_expr_mutator(Node *node,
 116                                            fix_upper_expr_context *context);
 117 static bool fix_opfuncids_walker(Node *node, void *context);
 118 static bool extract_query_dependencies_walker(Node *node,
 119                                                                                           PlannerGlobal *context);
 120
 121
 122 /*****************************************************************************
 123  *
 124  *              SUBPLAN REFERENCES
 125  *
 126  *****************************************************************************/
 127
 128 /*
 129  * set_plan_references
 130  *
 131  * This is the final processing pass of the planner/optimizer.  The plan
 132  * tree is complete; we just have to adjust some representational details
 133  * for the convenience of the executor:
 134  *
 135  * 1. We flatten the various subquery rangetables into a single list, and
 136  * zero out RangeTblEntry fields that are not useful to the executor.
 137  *
 138  * 2. We adjust Vars in scan nodes to be consistent with the flat rangetable.
 139  *
 140  * 3. We adjust Vars in upper plan nodes to refer to the outputs of their
 141  * subplans.
 142  *
 143  * 4. We compute regproc OIDs for operators (ie, we look up the function
 144  * that implements each op).
 145  *
 146  * 5. We create lists of specific objects that the plan depends on.
 147  * This will be used by plancache.c to drive invalidation of cached plans.
 148  * Relation dependencies are represented by OIDs, and everything else by
 149  * PlanInvalItems (this distinction is motivated by the shared-inval APIs).
 150  * Currently, relations and user-defined functions are the only types of
 151  * objects that are explicitly tracked this way.
 152  *
 153  * We also perform one final optimization step, which is to delete
 154  * SubqueryScan plan nodes that aren't doing anything useful (ie, have
 155  * no qual and a no-op targetlist).  The reason for doing this last is that
 156  * it can't readily be done before set_plan_references, because it would
 157  * break set_upper_references: the Vars in the subquery's top tlist
 158  * wouldn't match up with the Vars in the outer plan tree.  The SubqueryScan
 159  * serves a necessary function as a buffer between outer query and subquery
 160  * variable numbering ... but after we've flattened the rangetable this is
 161  * no longer a problem, since then there's only one rtindex namespace.
 162  *
 163  * set_plan_references recursively traverses the whole plan tree.
 164  *
 165  * Inputs:
 166  *      glob: global data for planner run
 167  *      plan: the topmost node of the plan
 168  *      rtable: the rangetable for the current subquery
 169  *
 170  * The return value is normally the same Plan node passed in, but can be
 171  * different when the passed-in Plan is a SubqueryScan we decide isn't needed.
 172  *
 173  * The flattened rangetable entries are appended to glob->finalrtable, and
 174  * plan dependencies are appended to glob->relationOids (for relations)
 175  * and glob->invalItems (for everything else).
 176  *
 177  * Notice that we modify Plan nodes in-place, but use expression_tree_mutator
 178  * to process targetlist and qual expressions.  We can assume that the Plan
 179  * nodes were just built by the planner and are not multiply referenced, but
 180  * it's not so safe to assume that for expression tree nodes.
 181  */
 182 Plan *
 183 set_plan_references(PlannerGlobal *glob, Plan *plan, List *rtable)
 184 {
 185         int                     rtoffset = list_length(glob->finalrtable);
 186         ListCell   *lc;
 187
 188         /*
 189          * In the flat rangetable, we zero out substructure pointers that are not
 190          * needed by the executor; this reduces the storage space and copying cost
 191          * for cached plans.  We keep only the alias and eref Alias fields, which
 192          * are needed by EXPLAIN.
 193          */
 194         foreach(lc, rtable)
 195         {
 196                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
 197                 RangeTblEntry *newrte;
 198
 199                 /* flat copy to duplicate all the scalar fields */
 200                 newrte = (RangeTblEntry *) palloc(sizeof(RangeTblEntry));
 201                 memcpy(newrte, rte, sizeof(RangeTblEntry));
 202
 203                 /* zap unneeded sub-structure */
 204                 newrte->subquery = NULL;
 205                 newrte->joinaliasvars = NIL;
 206                 newrte->funcexpr = NULL;
 207                 newrte->funccoltypes = NIL;
 208                 newrte->funccoltypmods = NIL;
 209                 newrte->values_lists = NIL;
 210                 newrte->ctecoltypes = NIL;
 211                 newrte->ctecoltypmods = NIL;
 212
 213                 glob->finalrtable = lappend(glob->finalrtable, newrte);
 214
 215                 /*
 216                  * If it's a plain relation RTE, add the table to relationOids.
 217                  *
 218                  * We do this even though the RTE might be unreferenced in the plan
 219                  * tree; this would correspond to cases such as views that were
 220                  * expanded, child tables that were eliminated by constraint
 221                  * exclusion, etc.      Schema invalidation on such a rel must still force
 222                  * rebuilding of the plan.
 223                  *
 224                  * Note we don't bother to avoid duplicate list entries.  We could,
 225                  * but it would probably cost more cycles than it would save.
 226                  */
 227                 if (newrte->rtekind == RTE_RELATION)
 228                         glob->relationOids = lappend_oid(glob->relationOids,
 229                                                                                          newrte->relid);
 230         }
 231
 232         /* Now fix the Plan tree */
 233         return set_plan_refs(glob, plan, rtoffset);
 234 }
 235
 236 /*
 237  * set_plan_refs: recurse through the Plan nodes of a single subquery level
 238  */
 239 static Plan *
 240 set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset)
 241 {
 242         ListCell   *l;
 243
 244         if (plan == NULL)
 245                 return NULL;
 246
 247         /*
 248          * Plan-type-specific fixes
 249          */
 250         switch (nodeTag(plan))
 251         {
 252                 case T_SeqScan:
 253                         {
 254                                 SeqScan    *splan = (SeqScan *) plan;
 255
 256                                 splan->scanrelid += rtoffset;
 257                                 splan->plan.targetlist =
 258                                         fix_scan_list(glob, splan->plan.targetlist, rtoffset);
 259                                 splan->plan.qual =
 260                                         fix_scan_list(glob, splan->plan.qual, rtoffset);
 261                         }
 262                         break;
 263                 case T_IndexScan:
 264                         {
 265                                 IndexScan  *splan = (IndexScan *) plan;
 266
 267                                 splan->scan.scanrelid += rtoffset;
 268                                 splan->scan.plan.targetlist =
 269                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 270                                 splan->scan.plan.qual =
 271                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 272                                 splan->indexqual =
 273                                         fix_scan_list(glob, splan->indexqual, rtoffset);
 274                                 splan->indexqualorig =
 275                                         fix_scan_list(glob, splan->indexqualorig, rtoffset);
 276                         }
 277                         break;
 278                 case T_BitmapIndexScan:
 279                         {
 280                                 BitmapIndexScan *splan = (BitmapIndexScan *) plan;
 281
 282                                 splan->scan.scanrelid += rtoffset;
 283                                 /* no need to fix targetlist and qual */
 284                                 Assert(splan->scan.plan.targetlist == NIL);
 285                                 Assert(splan->scan.plan.qual == NIL);
 286                                 splan->indexqual =
 287                                         fix_scan_list(glob, splan->indexqual, rtoffset);
 288                                 splan->indexqualorig =
 289                                         fix_scan_list(glob, splan->indexqualorig, rtoffset);
 290                         }
 291                         break;
 292                 case T_BitmapHeapScan:
 293                         {
 294                                 BitmapHeapScan *splan = (BitmapHeapScan *) plan;
 295
 296                                 splan->scan.scanrelid += rtoffset;
 297                                 splan->scan.plan.targetlist =
 298                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 299                                 splan->scan.plan.qual =
 300                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 301                                 splan->bitmapqualorig =
 302                                         fix_scan_list(glob, splan->bitmapqualorig, rtoffset);
 303                         }
 304                         break;
 305                 case T_TidScan:
 306                         {
 307                                 TidScan    *splan = (TidScan *) plan;
 308
 309                                 splan->scan.scanrelid += rtoffset;
 310                                 splan->scan.plan.targetlist =
 311                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 312                                 splan->scan.plan.qual =
 313                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 314                                 splan->tidquals =
 315                                         fix_scan_list(glob, splan->tidquals, rtoffset);
 316                         }
 317                         break;
 318                 case T_SubqueryScan:
 319                         /* Needs special treatment, see comments below */
 320                         return set_subqueryscan_references(glob,
 321                                                                                            (SubqueryScan *) plan,
 322                                                                                            rtoffset);
 323                 case T_FunctionScan:
 324                         {
 325                                 FunctionScan *splan = (FunctionScan *) plan;
 326
 327                                 splan->scan.scanrelid += rtoffset;
 328                                 splan->scan.plan.targetlist =
 329                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 330                                 splan->scan.plan.qual =
 331                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 332                                 splan->funcexpr =
 333                                         fix_scan_expr(glob, splan->funcexpr, rtoffset);
 334                         }
 335                         break;
 336                 case T_ValuesScan:
 337                         {
 338                                 ValuesScan *splan = (ValuesScan *) plan;
 339
 340                                 splan->scan.scanrelid += rtoffset;
 341                                 splan->scan.plan.targetlist =
 342                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 343                                 splan->scan.plan.qual =
 344                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 345                                 splan->values_lists =
 346                                         fix_scan_list(glob, splan->values_lists, rtoffset);
 347                         }
 348                         break;
 349                 case T_CteScan:
 350                         {
 351                                 CteScan *splan = (CteScan *) plan;
 352
 353                                 splan->scan.scanrelid += rtoffset;
 354                                 splan->scan.plan.targetlist =
 355                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 356                                 splan->scan.plan.qual =
 357                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 358                         }
 359                         break;
 360                 case T_WorkTableScan:
 361                         {
 362                                 WorkTableScan *splan = (WorkTableScan *) plan;
 363
 364                                 splan->scan.scanrelid += rtoffset;
 365                                 splan->scan.plan.targetlist =
 366                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 367                                 splan->scan.plan.qual =
 368                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 369                         }
 370                         break;
 371                 case T_NestLoop:
 372                 case T_MergeJoin:
 373                 case T_HashJoin:
 374                         set_join_references(glob, (Join *) plan, rtoffset);
 375                         break;
 376
 377                 case T_Hash:
 378                 case T_Material:
 379                 case T_Sort:
 380                 case T_Unique:
 381                 case T_SetOp:
 382
 383                         /*
 384                          * These plan types don't actually bother to evaluate their
 385                          * targetlists, because they just return their unmodified input
 386                          * tuples.      Even though the targetlist won't be used by the
 387                          * executor, we fix it up for possible use by EXPLAIN (not to
 388                          * mention ease of debugging --- wrong varnos are very confusing).
 389                          */
 390                         set_dummy_tlist_references(plan, rtoffset);
 391
 392                         /*
 393                          * Since these plan types don't check quals either, we should not
 394                          * find any qual expression attached to them.
 395                          */
 396                         Assert(plan->qual == NIL);
 397                         break;
 398                 case T_Limit:
 399                         {
 400                                 Limit      *splan = (Limit *) plan;
 401
 402                                 /*
 403                                  * Like the plan types above, Limit doesn't evaluate its tlist
 404                                  * or quals.  It does have live expressions for limit/offset,
 405                                  * however; and those cannot contain subplan variable refs, so
 406                                  * fix_scan_expr works for them.
 407                                  */
 408                                 set_dummy_tlist_references(plan, rtoffset);
 409                                 Assert(splan->plan.qual == NIL);
 410
 411                                 splan->limitOffset =
 412                                         fix_scan_expr(glob, splan->limitOffset, rtoffset);
 413                                 splan->limitCount =
 414                                         fix_scan_expr(glob, splan->limitCount, rtoffset);
 415                         }
 416                         break;
 417                 case T_Agg:
 418                 case T_Group:
 419                         set_upper_references(glob, plan, rtoffset);
 420                         break;
 421                 case T_Result:
 422                         {
 423                                 Result     *splan = (Result *) plan;
 424
 425                                 /*
 426                                  * Result may or may not have a subplan; if not, it's more
 427                                  * like a scan node than an upper node.
 428                                  */
 429                                 if (splan->plan.lefttree != NULL)
 430                                         set_upper_references(glob, plan, rtoffset);
 431                                 else
 432                                 {
 433                                         splan->plan.targetlist =
 434                                                 fix_scan_list(glob, splan->plan.targetlist, rtoffset);
 435                                         splan->plan.qual =
 436                                                 fix_scan_list(glob, splan->plan.qual, rtoffset);
 437                                 }
 438                                 /* resconstantqual can't contain any subplan variable refs */
 439                                 splan->resconstantqual =
 440                                         fix_scan_expr(glob, splan->resconstantqual, rtoffset);
 441                         }
 442                         break;
 443                 case T_Append:
 444                         {
 445                                 Append     *splan = (Append *) plan;
 446
 447                                 /*
 448                                  * Append, like Sort et al, doesn't actually evaluate its
 449                                  * targetlist or check quals.
 450                                  */
 451                                 set_dummy_tlist_references(plan, rtoffset);
 452                                 Assert(splan->plan.qual == NIL);
 453                                 foreach(l, splan->appendplans)
 454                                 {
 455                                         lfirst(l) = set_plan_refs(glob,
 456                                                                                           (Plan *) lfirst(l),
 457                                                                                           rtoffset);
 458                                 }
 459                         }
 460                         break;
 461                 case T_RecursiveUnion:
 462                         /* This doesn't evaluate targetlist or check quals either */
 463                         set_dummy_tlist_references(plan, rtoffset);
 464                         Assert(plan->qual == NIL);
 465                         break;
 466                 case T_BitmapAnd:
 467                         {
 468                                 BitmapAnd  *splan = (BitmapAnd *) plan;
 469
 470                                 /* BitmapAnd works like Append, but has no tlist */
 471                                 Assert(splan->plan.targetlist == NIL);
 472                                 Assert(splan->plan.qual == NIL);
 473                                 foreach(l, splan->bitmapplans)
 474                                 {
 475                                         lfirst(l) = set_plan_refs(glob,
 476                                                                                           (Plan *) lfirst(l),
 477                                                                                           rtoffset);
 478                                 }
 479                         }
 480                         break;
 481                 case T_BitmapOr:
 482                         {
 483                                 BitmapOr   *splan = (BitmapOr *) plan;
 484
 485                                 /* BitmapOr works like Append, but has no tlist */
 486                                 Assert(splan->plan.targetlist == NIL);
 487                                 Assert(splan->plan.qual == NIL);
 488                                 foreach(l, splan->bitmapplans)
 489                                 {
 490                                         lfirst(l) = set_plan_refs(glob,
 491                                                                                           (Plan *) lfirst(l),
 492                                                                                           rtoffset);
 493                                 }
 494                         }
 495                         break;
 496                 default:
 497                         elog(ERROR, "unrecognized node type: %d",
 498                                  (int) nodeTag(plan));
 499                         break;
 500         }
 501
 502         /*
 503          * Now recurse into child plans, if any
 504          *
 505          * NOTE: it is essential that we recurse into child plans AFTER we set
 506          * subplan references in this plan's tlist and quals.  If we did the
 507          * reference-adjustments bottom-up, then we would fail to match this
 508          * plan's var nodes against the already-modified nodes of the children.
 509          */
 510         plan->lefttree = set_plan_refs(glob, plan->lefttree, rtoffset);
 511         plan->righttree = set_plan_refs(glob, plan->righttree, rtoffset);
 512
 513         return plan;
 514 }
 515
 516 /*
 517  * set_subqueryscan_references
 518  *              Do set_plan_references processing on a SubqueryScan
 519  *
 520  * We try to strip out the SubqueryScan entirely; if we can't, we have
 521  * to do the normal processing on it.
 522  */
 523 static Plan *
 524 set_subqueryscan_references(PlannerGlobal *glob,
 525                                                         SubqueryScan *plan,
 526                                                         int rtoffset)
 527 {
 528         Plan       *result;
 529
 530         /* First, recursively process the subplan */
 531         plan->subplan = set_plan_references(glob, plan->subplan, plan->subrtable);
 532
 533         /* subrtable is no longer needed in the plan tree */
 534         plan->subrtable = NIL;
 535
 536         if (trivial_subqueryscan(plan))
 537         {
 538                 /*
 539                  * We can omit the SubqueryScan node and just pull up the subplan.
 540                  */
 541                 ListCell   *lp,
 542                                    *lc;
 543
 544                 result = plan->subplan;
 545
 546                 /* We have to be sure we don't lose any initplans */
 547                 result->initPlan = list_concat(plan->scan.plan.initPlan,
 548                                                                            result->initPlan);
 549
 550                 /*
 551                  * We also have to transfer the SubqueryScan's result-column names
 552                  * into the subplan, else columns sent to client will be improperly
 553                  * labeled if this is the topmost plan level.  Copy the "source
 554                  * column" information too.
 555                  */
 556                 forboth(lp, plan->scan.plan.targetlist, lc, result->targetlist)
 557                 {
 558                         TargetEntry *ptle = (TargetEntry *) lfirst(lp);
 559                         TargetEntry *ctle = (TargetEntry *) lfirst(lc);
 560
 561                         ctle->resname = ptle->resname;
 562                         ctle->resorigtbl = ptle->resorigtbl;
 563                         ctle->resorigcol = ptle->resorigcol;
 564                 }
 565         }
 566         else
 567         {
 568                 /*
 569                  * Keep the SubqueryScan node.  We have to do the processing that
 570                  * set_plan_references would otherwise have done on it.  Notice we do
 571                  * not do set_upper_references() here, because a SubqueryScan will
 572                  * always have been created with correct references to its subplan's
 573                  * outputs to begin with.
 574                  */
 575                 plan->scan.scanrelid += rtoffset;
 576                 plan->scan.plan.targetlist =
 577                         fix_scan_list(glob, plan->scan.plan.targetlist, rtoffset);
 578                 plan->scan.plan.qual =
 579                         fix_scan_list(glob, plan->scan.plan.qual, rtoffset);
 580
 581                 result = (Plan *) plan;
 582         }
 583
 584         return result;
 585 }
 586
 587 /*
 588  * trivial_subqueryscan
 589  *              Detect whether a SubqueryScan can be deleted from the plan tree.
 590  *
 591  * We can delete it if it has no qual to check and the targetlist just
 592  * regurgitates the output of the child plan.
 593  */
 594 static bool
 595 trivial_subqueryscan(SubqueryScan *plan)
 596 {
 597         int                     attrno;
 598         ListCell   *lp,
 599                            *lc;
 600
 601         if (plan->scan.plan.qual != NIL)
 602                 return false;
 603
 604         if (list_length(plan->scan.plan.targetlist) !=
 605                 list_length(plan->subplan->targetlist))
 606                 return false;                   /* tlists not same length */
 607
 608         attrno = 1;
 609         forboth(lp, plan->scan.plan.targetlist, lc, plan->subplan->targetlist)
 610         {
 611                 TargetEntry *ptle = (TargetEntry *) lfirst(lp);
 612                 TargetEntry *ctle = (TargetEntry *) lfirst(lc);
 613
 614                 if (ptle->resjunk != ctle->resjunk)
 615                         return false;           /* tlist doesn't match junk status */
 616
 617                 /*
 618                  * We accept either a Var referencing the corresponding element of the
 619                  * subplan tlist, or a Const equaling the subplan element. See
 620                  * generate_setop_tlist() for motivation.
 621                  */
 622                 if (ptle->expr && IsA(ptle->expr, Var))
 623                 {
 624                         Var                *var = (Var *) ptle->expr;
 625
 626                         Assert(var->varno == plan->scan.scanrelid);
 627                         Assert(var->varlevelsup == 0);
 628                         if (var->varattno != attrno)
 629                                 return false;   /* out of order */
 630                 }
 631                 else if (ptle->expr && IsA(ptle->expr, Const))
 632                 {
 633                         if (!equal(ptle->expr, ctle->expr))
 634                                 return false;
 635                 }
 636                 else
 637                         return false;
 638
 639                 attrno++;
 640         }
 641
 642         return true;
 643 }
 644
 645 /*
 646  * copyVar
 647  *              Copy a Var node.
 648  *
 649  * fix_scan_expr and friends do this enough times that it's worth having
 650  * a bespoke routine instead of using the generic copyObject() function.
 651  */
 652 static inline Var *
 653 copyVar(Var *var)
 654 {
 655         Var                *newvar = (Var *) palloc(sizeof(Var));
 656
 657         *newvar = *var;
 658         return newvar;
 659 }
 660
 661 /*
 662  * fix_expr_common
 663  *              Do generic set_plan_references processing on an expression node
 664  *
 665  * This is code that is common to all variants of expression-fixing.
 666  * We must look up operator opcode info for OpExpr and related nodes,
 667  * add OIDs from regclass Const nodes into glob->relationOids,
 668  * and add catalog TIDs for user-defined functions into glob->invalItems.
 669  *
 670  * We assume it's okay to update opcode info in-place.  So this could possibly
 671  * scribble on the planner's input data structures, but it's OK.
 672  */
 673 static void
 674 fix_expr_common(PlannerGlobal *glob, Node *node)
 675 {
 676         /* We assume callers won't call us on a NULL pointer */
 677         if (IsA(node, Aggref))
 678         {
 679                 record_plan_function_dependency(glob,
 680                                                                                 ((Aggref *) node)->aggfnoid);
 681         }
 682         else if (IsA(node, FuncExpr))
 683         {
 684                 record_plan_function_dependency(glob,
 685                                                                                 ((FuncExpr *) node)->funcid);
 686         }
 687         else if (IsA(node, OpExpr))
 688         {
 689                 set_opfuncid((OpExpr *) node);
 690                 record_plan_function_dependency(glob,
 691                                                                                 ((OpExpr *) node)->opfuncid);
 692         }
 693         else if (IsA(node, DistinctExpr))
 694         {
 695                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
 696                 record_plan_function_dependency(glob,
 697                                                                                 ((DistinctExpr *) node)->opfuncid);
 698         }
 699         else if (IsA(node, NullIfExpr))
 700         {
 701                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
 702                 record_plan_function_dependency(glob,
 703                                                                                 ((NullIfExpr *) node)->opfuncid);
 704         }
 705         else if (IsA(node, ScalarArrayOpExpr))
 706         {
 707                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
 708                 record_plan_function_dependency(glob,
 709                                                                                 ((ScalarArrayOpExpr *) node)->opfuncid);
 710         }
 711         else if (IsA(node, ArrayCoerceExpr))
 712         {
 713                 if (OidIsValid(((ArrayCoerceExpr *) node)->elemfuncid))
 714                         record_plan_function_dependency(glob,
 715                                                                                         ((ArrayCoerceExpr *) node)->elemfuncid);
 716         }
 717         else if (IsA(node, Const))
 718         {
 719                 Const      *con = (Const *) node;
 720
 721                 /* Check for regclass reference */
 722                 if (ISREGCLASSCONST(con))
 723                         glob->relationOids =
 724                                 lappend_oid(glob->relationOids,
 725                                                         DatumGetObjectId(con->constvalue));
 726         }
 727 }
 728
 729 /*
 730  * fix_scan_expr
 731  *              Do set_plan_references processing on a scan-level expression
 732  *
 733  * This consists of incrementing all Vars' varnos by rtoffset,
 734  * looking up operator opcode info for OpExpr and related nodes,
 735  * and adding OIDs from regclass Const nodes into glob->relationOids.
 736  */
 737 static Node *
 738 fix_scan_expr(PlannerGlobal *glob, Node *node, int rtoffset)
 739 {
 740         fix_scan_expr_context context;
 741
 742         context.glob = glob;
 743         context.rtoffset = rtoffset;
 744
 745         if (rtoffset != 0 || glob->lastPHId != 0)
 746         {
 747                 return fix_scan_expr_mutator(node, &context);
 748         }
 749         else
 750         {
 751                 /*
 752                  * If rtoffset == 0, we don't need to change any Vars, and if there
 753                  * are no placeholders anywhere we won't need to remove them.  Then
 754                  * it's OK to just scribble on the input node tree instead of copying
 755                  * (since the only change, filling in any unset opfuncid fields,
 756                  * is harmless).  This saves just enough cycles to be noticeable on
 757                  * trivial queries.
 758                  */
 759                 (void) fix_scan_expr_walker(node, &context);
 760                 return node;
 761         }
 762 }
 763
 764 static Node *
 765 fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
 766 {
 767         if (node == NULL)
 768                 return NULL;
 769         if (IsA(node, Var))
 770         {
 771                 Var                *var = copyVar((Var *) node);
 772
 773                 Assert(var->varlevelsup == 0);
 774
 775                 /*
 776                  * We should not see any Vars marked INNER, but in a nestloop inner
 777                  * scan there could be OUTER Vars.      Leave them alone.
 778                  */
 779                 Assert(var->varno != INNER);
 780                 if (var->varno > 0 && var->varno != OUTER)
 781                         var->varno += context->rtoffset;
 782                 if (var->varnoold > 0)
 783                         var->varnoold += context->rtoffset;
 784                 return (Node *) var;
 785         }
 786         if (IsA(node, CurrentOfExpr))
 787         {
 788                 CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);
 789
 790                 Assert(cexpr->cvarno != INNER);
 791                 Assert(cexpr->cvarno != OUTER);
 792                 cexpr->cvarno += context->rtoffset;
 793                 return (Node *) cexpr;
 794         }
 795         if (IsA(node, PlaceHolderVar))
 796         {
 797                 /* At scan level, we should always just evaluate the contained expr */
 798                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
 799
 800                 return fix_scan_expr_mutator((Node *) phv->phexpr, context);
 801         }
 802         fix_expr_common(context->glob, node);
 803         return expression_tree_mutator(node, fix_scan_expr_mutator,
 804                                                                    (void *) context);
 805 }
 806
 807 static bool
 808 fix_scan_expr_walker(Node *node, fix_scan_expr_context *context)
 809 {
 810         if (node == NULL)
 811                 return false;
 812         Assert(!IsA(node, PlaceHolderVar));
 813         fix_expr_common(context->glob, node);
 814         return expression_tree_walker(node, fix_scan_expr_walker,
 815                                                                   (void *) context);
 816 }
 817
 818 /*
 819  * set_join_references
 820  *        Modify the target list and quals of a join node to reference its
 821  *        subplans, by setting the varnos to OUTER or INNER and setting attno
 822  *        values to the result domain number of either the corresponding outer
 823  *        or inner join tuple item.  Also perform opcode lookup for these
 824  *        expressions. and add regclass OIDs to glob->relationOids.
 825  *
 826  * In the case of a nestloop with inner indexscan, we will also need to
 827  * apply the same transformation to any outer vars appearing in the
 828  * quals of the child indexscan.  set_inner_join_references does that.
 829  */
 830 static void
 831 set_join_references(PlannerGlobal *glob, Join *join, int rtoffset)
 832 {
 833         Plan       *outer_plan = join->plan.lefttree;
 834         Plan       *inner_plan = join->plan.righttree;
 835         indexed_tlist *outer_itlist;
 836         indexed_tlist *inner_itlist;
 837
 838         outer_itlist = build_tlist_index(outer_plan->targetlist);
 839         inner_itlist = build_tlist_index(inner_plan->targetlist);
 840
 841         /* All join plans have tlist, qual, and joinqual */
 842         join->plan.targetlist = fix_join_expr(glob,
 843                                                                                   join->plan.targetlist,
 844                                                                                   outer_itlist,
 845                                                                                   inner_itlist,
 846                                                                                   (Index) 0,
 847                                                                                   rtoffset);
 848         join->plan.qual = fix_join_expr(glob,
 849                                                                         join->plan.qual,
 850                                                                         outer_itlist,
 851                                                                         inner_itlist,
 852                                                                         (Index) 0,
 853                                                                         rtoffset);
 854         join->joinqual = fix_join_expr(glob,
 855                                                                    join->joinqual,
 856                                                                    outer_itlist,
 857                                                                    inner_itlist,
 858                                                                    (Index) 0,
 859                                                                    rtoffset);
 860
 861         /* Now do join-type-specific stuff */
 862         if (IsA(join, NestLoop))
 863         {
 864                 /* This processing is split out to handle possible recursion */
 865                 set_inner_join_references(glob, inner_plan, outer_itlist);
 866         }
 867         else if (IsA(join, MergeJoin))
 868         {
 869                 MergeJoin  *mj = (MergeJoin *) join;
 870
 871                 mj->mergeclauses = fix_join_expr(glob,
 872                                                                                  mj->mergeclauses,
 873                                                                                  outer_itlist,
 874                                                                                  inner_itlist,
 875                                                                                  (Index) 0,
 876                                                                                  rtoffset);
 877         }
 878         else if (IsA(join, HashJoin))
 879         {
 880                 HashJoin   *hj = (HashJoin *) join;
 881
 882                 hj->hashclauses = fix_join_expr(glob,
 883                                                                                 hj->hashclauses,
 884                                                                                 outer_itlist,
 885                                                                                 inner_itlist,
 886                                                                                 (Index) 0,
 887                                                                                 rtoffset);
 888         }
 889
 890         pfree(outer_itlist);
 891         pfree(inner_itlist);
 892 }
 893
 894 /*
 895  * set_inner_join_references
 896  *              Handle join references appearing in an inner indexscan's quals
 897  *
 898  * To handle bitmap-scan plan trees, we have to be able to recurse down
 899  * to the bottom BitmapIndexScan nodes; likewise, appendrel indexscans
 900  * require recursing through Append nodes.      This is split out as a separate
 901  * function so that it can recurse.
 902  *
 903  * Note we do *not* apply any rtoffset for non-join Vars; this is because
 904  * the quals will be processed again by fix_scan_expr when the set_plan_refs
 905  * recursion reaches the inner indexscan, and so we'd have done it twice.
 906  */
 907 static void
 908 set_inner_join_references(PlannerGlobal *glob, Plan *inner_plan,
 909                                                   indexed_tlist *outer_itlist)
 910 {
 911         if (IsA(inner_plan, IndexScan))
 912         {
 913                 /*
 914                  * An index is being used to reduce the number of tuples scanned in
 915                  * the inner relation.  If there are join clauses being used with the
 916                  * index, we must update their outer-rel var nodes to refer to the
 917                  * outer side of the join.
 918                  */
 919                 IndexScan  *innerscan = (IndexScan *) inner_plan;
 920                 List       *indexqualorig = innerscan->indexqualorig;
 921
 922                 /* No work needed if indexqual refers only to its own rel... */
 923                 if (NumRelids((Node *) indexqualorig) > 1)
 924                 {
 925                         Index           innerrel = innerscan->scan.scanrelid;
 926
 927                         /* only refs to outer vars get changed in the inner qual */
 928                         innerscan->indexqualorig = fix_join_expr(glob,
 929                                                                                                          indexqualorig,
 930                                                                                                          outer_itlist,
 931                                                                                                          NULL,
 932                                                                                                          innerrel,
 933                                                                                                          0);
 934                         innerscan->indexqual = fix_join_expr(glob,
 935                                                                                                  innerscan->indexqual,
 936                                                                                                  outer_itlist,
 937                                                                                                  NULL,
 938                                                                                                  innerrel,
 939                                                                                                  0);
 940
 941                         /*
 942                          * We must fix the inner qpqual too, if it has join clauses (this
 943                          * could happen if special operators are involved: some indexquals
 944                          * may get rechecked as qpquals).
 945                          */
 946                         if (NumRelids((Node *) inner_plan->qual) > 1)
 947                                 inner_plan->qual = fix_join_expr(glob,
 948                                                                                                  inner_plan->qual,
 949                                                                                                  outer_itlist,
 950                                                                                                  NULL,
 951                                                                                                  innerrel,
 952                                                                                                  0);
 953                 }
 954         }
 955         else if (IsA(inner_plan, BitmapIndexScan))
 956         {
 957                 /*
 958                  * Same, but index is being used within a bitmap plan.
 959                  */
 960                 BitmapIndexScan *innerscan = (BitmapIndexScan *) inner_plan;
 961                 List       *indexqualorig = innerscan->indexqualorig;
 962
 963                 /* No work needed if indexqual refers only to its own rel... */
 964                 if (NumRelids((Node *) indexqualorig) > 1)
 965                 {
 966                         Index           innerrel = innerscan->scan.scanrelid;
 967
 968                         /* only refs to outer vars get changed in the inner qual */
 969                         innerscan->indexqualorig = fix_join_expr(glob,
 970                                                                                                          indexqualorig,
 971                                                                                                          outer_itlist,
 972                                                                                                          NULL,
 973                                                                                                          innerrel,
 974                                                                                                          0);
 975                         innerscan->indexqual = fix_join_expr(glob,
 976                                                                                                  innerscan->indexqual,
 977                                                                                                  outer_itlist,
 978                                                                                                  NULL,
 979                                                                                                  innerrel,
 980                                                                                                  0);
 981                         /* no need to fix inner qpqual */
 982                         Assert(inner_plan->qual == NIL);
 983                 }
 984         }
 985         else if (IsA(inner_plan, BitmapHeapScan))
 986         {
 987                 /*
 988                  * The inner side is a bitmap scan plan.  Fix the top node, and
 989                  * recurse to get the lower nodes.
 990                  *
 991                  * Note: create_bitmap_scan_plan removes clauses from bitmapqualorig
 992                  * if they are duplicated in qpqual, so must test these independently.
 993                  */
 994                 BitmapHeapScan *innerscan = (BitmapHeapScan *) inner_plan;
 995                 Index           innerrel = innerscan->scan.scanrelid;
 996                 List       *bitmapqualorig = innerscan->bitmapqualorig;
 997
 998                 /* only refs to outer vars get changed in the inner qual */
 999                 if (NumRelids((Node *) bitmapqualorig) > 1)
1000                         innerscan->bitmapqualorig = fix_join_expr(glob,
1001                                                                                                           bitmapqualorig,
1002                                                                                                           outer_itlist,
1003                                                                                                           NULL,
1004                                                                                                           innerrel,
1005                                                                                                           0);
1006
1007                 /*
1008                  * We must fix the inner qpqual too, if it has join clauses (this
1009                  * could happen if special operators are involved: some indexquals may
1010                  * get rechecked as qpquals).
1011                  */
1012                 if (NumRelids((Node *) inner_plan->qual) > 1)
1013                         inner_plan->qual = fix_join_expr(glob,
1014                                                                                          inner_plan->qual,
1015                                                                                          outer_itlist,
1016                                                                                          NULL,
1017                                                                                          innerrel,
1018                                                                                          0);
1019
1020                 /* Now recurse */
1021                 set_inner_join_references(glob, inner_plan->lefttree, outer_itlist);
1022         }
1023         else if (IsA(inner_plan, BitmapAnd))
1024         {
1025                 /* All we need do here is recurse */
1026                 BitmapAnd  *innerscan = (BitmapAnd *) inner_plan;
1027                 ListCell   *l;
1028
1029                 foreach(l, innerscan->bitmapplans)
1030                 {
1031                         set_inner_join_references(glob, (Plan *) lfirst(l), outer_itlist);
1032                 }
1033         }
1034         else if (IsA(inner_plan, BitmapOr))
1035         {
1036                 /* All we need do here is recurse */
1037                 BitmapOr   *innerscan = (BitmapOr *) inner_plan;
1038                 ListCell   *l;
1039
1040                 foreach(l, innerscan->bitmapplans)
1041                 {
1042                         set_inner_join_references(glob, (Plan *) lfirst(l), outer_itlist);
1043                 }
1044         }
1045         else if (IsA(inner_plan, TidScan))
1046         {
1047                 TidScan    *innerscan = (TidScan *) inner_plan;
1048                 Index           innerrel = innerscan->scan.scanrelid;
1049
1050                 innerscan->tidquals = fix_join_expr(glob,
1051                                                                                         innerscan->tidquals,
1052                                                                                         outer_itlist,
1053                                                                                         NULL,
1054                                                                                         innerrel,
1055                                                                                         0);
1056         }
1057         else if (IsA(inner_plan, Append))
1058         {
1059                 /*
1060                  * The inner side is an append plan.  Recurse to see if it contains
1061                  * indexscans that need to be fixed.
1062                  */
1063                 Append     *appendplan = (Append *) inner_plan;
1064                 ListCell   *l;
1065
1066                 foreach(l, appendplan->appendplans)
1067                 {
1068                         set_inner_join_references(glob, (Plan *) lfirst(l), outer_itlist);
1069                 }
1070         }
1071         else if (IsA(inner_plan, Result))
1072         {
1073                 /* Recurse through a gating Result node (similar to Append case) */
1074                 Result     *result = (Result *) inner_plan;
1075
1076                 if (result->plan.lefttree)
1077                         set_inner_join_references(glob, result->plan.lefttree, outer_itlist);
1078         }
1079 }
1080
1081 /*
1082  * set_upper_references
1083  *        Update the targetlist and quals of an upper-level plan node
1084  *        to refer to the tuples returned by its lefttree subplan.
1085  *        Also perform opcode lookup for these expressions, and
1086  *        add regclass OIDs to glob->relationOids.
1087  *
1088  * This is used for single-input plan types like Agg, Group, Result.
1089  *
1090  * In most cases, we have to match up individual Vars in the tlist and
1091  * qual expressions with elements of the subplan's tlist (which was
1092  * generated by flatten_tlist() from these selfsame expressions, so it
1093  * should have all the required variables).  There is an important exception,
1094  * however: GROUP BY and ORDER BY expressions will have been pushed into the
1095  * subplan tlist unflattened.  If these values are also needed in the output
1096  * then we want to reference the subplan tlist element rather than recomputing
1097  * the expression.
1098  */
1099 static void
1100 set_upper_references(PlannerGlobal *glob, Plan *plan, int rtoffset)
1101 {
1102         Plan       *subplan = plan->lefttree;
1103         indexed_tlist *subplan_itlist;
1104         List       *output_targetlist;
1105         ListCell   *l;
1106
1107         subplan_itlist = build_tlist_index(subplan->targetlist);
1108
1109         output_targetlist = NIL;
1110         foreach(l, plan->targetlist)
1111         {
1112                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1113                 Node       *newexpr;
1114
1115                 newexpr = fix_upper_expr(glob,
1116                                                                  (Node *) tle->expr,
1117                                                                  subplan_itlist,
1118                                                                  rtoffset);
1119                 tle = flatCopyTargetEntry(tle);
1120                 tle->expr = (Expr *) newexpr;
1121                 output_targetlist = lappend(output_targetlist, tle);
1122         }
1123         plan->targetlist = output_targetlist;
1124
1125         plan->qual = (List *)
1126                 fix_upper_expr(glob,
1127                                            (Node *) plan->qual,
1128                                            subplan_itlist,
1129                                            rtoffset);
1130
1131         pfree(subplan_itlist);
1132 }
1133
1134 /*
1135  * set_dummy_tlist_references
1136  *        Replace the targetlist of an upper-level plan node with a simple
1137  *        list of OUTER references to its child.
1138  *
1139  * This is used for plan types like Sort and Append that don't evaluate
1140  * their targetlists.  Although the executor doesn't care at all what's in
1141  * the tlist, EXPLAIN needs it to be realistic.
1142  *
1143  * Note: we could almost use set_upper_references() here, but it fails for
1144  * Append for lack of a lefttree subplan.  Single-purpose code is faster
1145  * anyway.
1146  */
1147 static void
1148 set_dummy_tlist_references(Plan *plan, int rtoffset)
1149 {
1150         List       *output_targetlist;
1151         ListCell   *l;
1152
1153         output_targetlist = NIL;
1154         foreach(l, plan->targetlist)
1155         {
1156                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1157                 Var                *oldvar = (Var *) tle->expr;
1158                 Var                *newvar;
1159
1160                 newvar = makeVar(OUTER,
1161                                                  tle->resno,
1162                                                  exprType((Node *) oldvar),
1163                                                  exprTypmod((Node *) oldvar),
1164                                                  0);
1165                 if (IsA(oldvar, Var))
1166                 {
1167                         newvar->varnoold = oldvar->varno + rtoffset;
1168                         newvar->varoattno = oldvar->varattno;
1169                 }
1170                 else
1171                 {
1172                         newvar->varnoold = 0;           /* wasn't ever a plain Var */
1173                         newvar->varoattno = 0;
1174                 }
1175
1176                 tle = flatCopyTargetEntry(tle);
1177                 tle->expr = (Expr *) newvar;
1178                 output_targetlist = lappend(output_targetlist, tle);
1179         }
1180         plan->targetlist = output_targetlist;
1181
1182         /* We don't touch plan->qual here */
1183 }
1184
1185
1186 /*
1187  * build_tlist_index --- build an index data structure for a child tlist
1188  *
1189  * In most cases, subplan tlists will be "flat" tlists with only Vars,
1190  * so we try to optimize that case by extracting information about Vars
1191  * in advance.  Matching a parent tlist to a child is still an O(N^2)
1192  * operation, but at least with a much smaller constant factor than plain
1193  * tlist_member() searches.
1194  *
1195  * The result of this function is an indexed_tlist struct to pass to
1196  * search_indexed_tlist_for_var() or search_indexed_tlist_for_non_var().
1197  * When done, the indexed_tlist may be freed with a single pfree().
1198  */
1199 static indexed_tlist *
1200 build_tlist_index(List *tlist)
1201 {
1202         indexed_tlist *itlist;
1203         tlist_vinfo *vinfo;
1204         ListCell   *l;
1205
1206         /* Create data structure with enough slots for all tlist entries */
1207         itlist = (indexed_tlist *)
1208                 palloc(offsetof(indexed_tlist, vars) +
1209                            list_length(tlist) * sizeof(tlist_vinfo));
1210
1211         itlist->tlist = tlist;
1212         itlist->has_ph_vars = false;
1213         itlist->has_non_vars = false;
1214
1215         /* Find the Vars and fill in the index array */
1216         vinfo = itlist->vars;
1217         foreach(l, tlist)
1218         {
1219                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1220
1221                 if (tle->expr && IsA(tle->expr, Var))
1222                 {
1223                         Var                *var = (Var *) tle->expr;
1224
1225                         vinfo->varno = var->varno;
1226                         vinfo->varattno = var->varattno;
1227                         vinfo->resno = tle->resno;
1228                         vinfo++;
1229                 }
1230                 else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
1231                         itlist->has_ph_vars = true;
1232                 else
1233                         itlist->has_non_vars = true;
1234         }
1235
1236         itlist->num_vars = (vinfo - itlist->vars);
1237
1238         return itlist;
1239 }
1240
1241 /*
1242  * build_tlist_index_other_vars --- build a restricted tlist index
1243  *
1244  * This is like build_tlist_index, but we only index tlist entries that
1245  * are Vars belonging to some rel other than the one specified.  We will set
1246  * has_ph_vars (allowing PlaceHolderVars to be matched), but not has_non_vars
1247  * (so nothing other than Vars and PlaceHolderVars can be matched).
1248  */
1249 static indexed_tlist *
1250 build_tlist_index_other_vars(List *tlist, Index ignore_rel)
1251 {
1252         indexed_tlist *itlist;
1253         tlist_vinfo *vinfo;
1254         ListCell   *l;
1255
1256         /* Create data structure with enough slots for all tlist entries */
1257         itlist = (indexed_tlist *)
1258                 palloc(offsetof(indexed_tlist, vars) +
1259                            list_length(tlist) * sizeof(tlist_vinfo));
1260
1261         itlist->tlist = tlist;
1262         itlist->has_ph_vars = false;
1263         itlist->has_non_vars = false;
1264
1265         /* Find the desired Vars and fill in the index array */
1266         vinfo = itlist->vars;
1267         foreach(l, tlist)
1268         {
1269                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1270
1271                 if (tle->expr && IsA(tle->expr, Var))
1272                 {
1273                         Var                *var = (Var *) tle->expr;
1274
1275                         if (var->varno != ignore_rel)
1276                         {
1277                                 vinfo->varno = var->varno;
1278                                 vinfo->varattno = var->varattno;
1279                                 vinfo->resno = tle->resno;
1280                                 vinfo++;
1281                         }
1282                 }
1283                 else if (tle->expr && IsA(tle->expr, PlaceHolderVar))
1284                         itlist->has_ph_vars = true;
1285         }
1286
1287         itlist->num_vars = (vinfo - itlist->vars);
1288
1289         return itlist;
1290 }
1291
1292 /*
1293  * search_indexed_tlist_for_var --- find a Var in an indexed tlist
1294  *
1295  * If a match is found, return a copy of the given Var with suitably
1296  * modified varno/varattno (to wit, newvarno and the resno of the TLE entry).
1297  * Also ensure that varnoold is incremented by rtoffset.
1298  * If no match, return NULL.
1299  */
1300 static Var *
1301 search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
1302                                                          Index newvarno, int rtoffset)
1303 {
1304         Index           varno = var->varno;
1305         AttrNumber      varattno = var->varattno;
1306         tlist_vinfo *vinfo;
1307         int                     i;
1308
1309         vinfo = itlist->vars;
1310         i = itlist->num_vars;
1311         while (i-- > 0)
1312         {
1313                 if (vinfo->varno == varno && vinfo->varattno == varattno)
1314                 {
1315                         /* Found a match */
1316                         Var                *newvar = copyVar(var);
1317
1318                         newvar->varno = newvarno;
1319                         newvar->varattno = vinfo->resno;
1320                         if (newvar->varnoold > 0)
1321                                 newvar->varnoold += rtoffset;
1322                         return newvar;
1323                 }
1324                 vinfo++;
1325         }
1326         return NULL;                            /* no match */
1327 }
1328
1329 /*
1330  * search_indexed_tlist_for_non_var --- find a non-Var in an indexed tlist
1331  *
1332  * If a match is found, return a Var constructed to reference the tlist item.
1333  * If no match, return NULL.
1334  *
1335  * NOTE: it is a waste of time to call this unless itlist->has_ph_vars or
1336  * itlist->has_non_vars
1337  */
1338 static Var *
1339 search_indexed_tlist_for_non_var(Node *node,
1340                                                                  indexed_tlist *itlist, Index newvarno)
1341 {
1342         TargetEntry *tle;
1343
1344         tle = tlist_member(node, itlist->tlist);
1345         if (tle)
1346         {
1347                 /* Found a matching subplan output expression */
1348                 Var                *newvar;
1349
1350                 newvar = makeVar(newvarno,
1351                                                  tle->resno,
1352                                                  exprType((Node *) tle->expr),
1353                                                  exprTypmod((Node *) tle->expr),
1354                                                  0);
1355                 newvar->varnoold = 0;   /* wasn't ever a plain Var */
1356                 newvar->varoattno = 0;
1357                 return newvar;
1358         }
1359         return NULL;                            /* no match */
1360 }
1361
1362 /*
1363  * fix_join_expr
1364  *         Create a new set of targetlist entries or join qual clauses by
1365  *         changing the varno/varattno values of variables in the clauses
1366  *         to reference target list values from the outer and inner join
1367  *         relation target lists.  Also perform opcode lookup and add
1368  *         regclass OIDs to glob->relationOids.
1369  *
1370  * This is used in two different scenarios: a normal join clause, where
1371  * all the Vars in the clause *must* be replaced by OUTER or INNER references;
1372  * and an indexscan being used on the inner side of a nestloop join.
1373  * In the latter case we want to replace the outer-relation Vars by OUTER
1374  * references, while Vars of the inner relation should be adjusted by rtoffset.
1375  * (We also implement RETURNING clause fixup using this second scenario.)
1376  *
1377  * For a normal join, acceptable_rel should be zero so that any failure to
1378  * match a Var will be reported as an error.  For the indexscan case,
1379  * pass inner_itlist = NULL and acceptable_rel = the (not-offseted-yet) ID
1380  * of the inner relation.
1381  *
1382  * 'clauses' is the targetlist or list of join clauses
1383  * 'outer_itlist' is the indexed target list of the outer join relation
1384  * 'inner_itlist' is the indexed target list of the inner join relation,
1385  *              or NULL
1386  * 'acceptable_rel' is either zero or the rangetable index of a relation
1387  *              whose Vars may appear in the clause without provoking an error.
1388  * 'rtoffset' is what to add to varno for Vars of acceptable_rel.
1389  *
1390  * Returns the new expression tree.  The original clause structure is
1391  * not modified.
1392  */
1393 static List *
1394 fix_join_expr(PlannerGlobal *glob,
1395                           List *clauses,
1396                           indexed_tlist *outer_itlist,
1397                           indexed_tlist *inner_itlist,
1398                           Index acceptable_rel,
1399                           int rtoffset)
1400 {
1401         fix_join_expr_context context;
1402
1403         context.glob = glob;
1404         context.outer_itlist = outer_itlist;
1405         context.inner_itlist = inner_itlist;
1406         context.acceptable_rel = acceptable_rel;
1407         context.rtoffset = rtoffset;
1408         return (List *) fix_join_expr_mutator((Node *) clauses, &context);
1409 }
1410
1411 static Node *
1412 fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
1413 {
1414         Var                *newvar;
1415
1416         if (node == NULL)
1417                 return NULL;
1418         if (IsA(node, Var))
1419         {
1420                 Var                *var = (Var *) node;
1421
1422                 /* First look for the var in the input tlists */
1423                 newvar = search_indexed_tlist_for_var(var,
1424                                                                                           context->outer_itlist,
1425                                                                                           OUTER,
1426                                                                                           context->rtoffset);
1427                 if (newvar)
1428                         return (Node *) newvar;
1429                 if (context->inner_itlist)
1430                 {
1431                         newvar = search_indexed_tlist_for_var(var,
1432                                                                                                   context->inner_itlist,
1433                                                                                                   INNER,
1434                                                                                                   context->rtoffset);
1435                         if (newvar)
1436                                 return (Node *) newvar;
1437                 }
1438
1439                 /* If it's for acceptable_rel, adjust and return it */
1440                 if (var->varno == context->acceptable_rel)
1441                 {
1442                         var = copyVar(var);
1443                         var->varno += context->rtoffset;
1444                         var->varnoold += context->rtoffset;
1445                         return (Node *) var;
1446                 }
1447
1448                 /* No referent found for Var */
1449                 elog(ERROR, "variable not found in subplan target lists");
1450         }
1451         if (IsA(node, PlaceHolderVar))
1452         {
1453                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
1454
1455                 /* See if the PlaceHolderVar has bubbled up from a lower plan node */
1456                 if (context->outer_itlist->has_ph_vars)
1457                 {
1458                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1459                                                                                                           context->outer_itlist,
1460                                                                                                           OUTER);
1461                         if (newvar)
1462                                 return (Node *) newvar;
1463                 }
1464                 if (context->inner_itlist && context->inner_itlist->has_ph_vars)
1465                 {
1466                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1467                                                                                                           context->inner_itlist,
1468                                                                                                           INNER);
1469                         if (newvar)
1470                                 return (Node *) newvar;
1471                 }
1472
1473                 /* If not supplied by input plans, evaluate the contained expr */
1474                 return fix_join_expr_mutator((Node *) phv->phexpr, context);
1475         }
1476         /* Try matching more complex expressions too, if tlists have any */
1477         if (context->outer_itlist->has_non_vars)
1478         {
1479                 newvar = search_indexed_tlist_for_non_var(node,
1480                                                                                                   context->outer_itlist,
1481                                                                                                   OUTER);
1482                 if (newvar)
1483                         return (Node *) newvar;
1484         }
1485         if (context->inner_itlist && context->inner_itlist->has_non_vars)
1486         {
1487                 newvar = search_indexed_tlist_for_non_var(node,
1488                                                                                                   context->inner_itlist,
1489                                                                                                   INNER);
1490                 if (newvar)
1491                         return (Node *) newvar;
1492         }
1493         fix_expr_common(context->glob, node);
1494         return expression_tree_mutator(node,
1495                                                                    fix_join_expr_mutator,
1496                                                                    (void *) context);
1497 }
1498
1499 /*
1500  * fix_upper_expr
1501  *              Modifies an expression tree so that all Var nodes reference outputs
1502  *              of a subplan.  Also performs opcode lookup, and adds regclass OIDs to
1503  *              glob->relationOids.
1504  *
1505  * This is used to fix up target and qual expressions of non-join upper-level
1506  * plan nodes.
1507  *
1508  * An error is raised if no matching var can be found in the subplan tlist
1509  * --- so this routine should only be applied to nodes whose subplans'
1510  * targetlists were generated via flatten_tlist() or some such method.
1511  *
1512  * If itlist->has_non_vars is true, then we try to match whole subexpressions
1513  * against elements of the subplan tlist, so that we can avoid recomputing
1514  * expressions that were already computed by the subplan.  (This is relatively
1515  * expensive, so we don't want to try it in the common case where the
1516  * subplan tlist is just a flattened list of Vars.)
1517  *
1518  * 'node': the tree to be fixed (a target item or qual)
1519  * 'subplan_itlist': indexed target list for subplan
1520  * 'rtoffset': how much to increment varnoold by
1521  *
1522  * The resulting tree is a copy of the original in which all Var nodes have
1523  * varno = OUTER, varattno = resno of corresponding subplan target.
1524  * The original tree is not modified.
1525  */
1526 static Node *
1527 fix_upper_expr(PlannerGlobal *glob,
1528                            Node *node,
1529                            indexed_tlist *subplan_itlist,
1530                            int rtoffset)
1531 {
1532         fix_upper_expr_context context;
1533
1534         context.glob = glob;
1535         context.subplan_itlist = subplan_itlist;
1536         context.rtoffset = rtoffset;
1537         return fix_upper_expr_mutator(node, &context);
1538 }
1539
1540 static Node *
1541 fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
1542 {
1543         Var                *newvar;
1544
1545         if (node == NULL)
1546                 return NULL;
1547         if (IsA(node, Var))
1548         {
1549                 Var                *var = (Var *) node;
1550
1551                 newvar = search_indexed_tlist_for_var(var,
1552                                                                                           context->subplan_itlist,
1553                                                                                           OUTER,
1554                                                                                           context->rtoffset);
1555                 if (!newvar)
1556                         elog(ERROR, "variable not found in subplan target list");
1557                 return (Node *) newvar;
1558         }
1559         if (IsA(node, PlaceHolderVar))
1560         {
1561                 PlaceHolderVar *phv = (PlaceHolderVar *) node;
1562
1563                 /* See if the PlaceHolderVar has bubbled up from a lower plan node */
1564                 if (context->subplan_itlist->has_ph_vars)
1565                 {
1566                         newvar = search_indexed_tlist_for_non_var((Node *) phv,
1567                                                                                                           context->subplan_itlist,
1568                                                                                                           OUTER);
1569                         if (newvar)
1570                                 return (Node *) newvar;
1571                 }
1572                 /* If not supplied by input plan, evaluate the contained expr */
1573                 return fix_upper_expr_mutator((Node *) phv->phexpr, context);
1574         }
1575         /* Try matching more complex expressions too, if tlist has any */
1576         if (context->subplan_itlist->has_non_vars)
1577         {
1578                 newvar = search_indexed_tlist_for_non_var(node,
1579                                                                                                   context->subplan_itlist,
1580                                                                                                   OUTER);
1581                 if (newvar)
1582                         return (Node *) newvar;
1583         }
1584         fix_expr_common(context->glob, node);
1585         return expression_tree_mutator(node,
1586                                                                    fix_upper_expr_mutator,
1587                                                                    (void *) context);
1588 }
1589
1590 /*
1591  * set_returning_clause_references
1592  *              Perform setrefs.c's work on a RETURNING targetlist
1593  *
1594  * If the query involves more than just the result table, we have to
1595  * adjust any Vars that refer to other tables to reference junk tlist
1596  * entries in the top plan's targetlist.  Vars referencing the result
1597  * table should be left alone, however (the executor will evaluate them
1598  * using the actual heap tuple, after firing triggers if any).  In the
1599  * adjusted RETURNING list, result-table Vars will still have their
1600  * original varno, but Vars for other rels will have varno OUTER.
1601  *
1602  * We also must perform opcode lookup and add regclass OIDs to
1603  * glob->relationOids.
1604  *
1605  * 'rlist': the RETURNING targetlist to be fixed
1606  * 'topplan': the top Plan node for the query (not yet passed through
1607  *              set_plan_references)
1608  * 'resultRelation': RT index of the associated result relation
1609  *
1610  * Note: we assume that result relations will have rtoffset zero, that is,
1611  * they are not coming from a subplan.
1612  */
1613 List *
1614 set_returning_clause_references(PlannerGlobal *glob,
1615                                                                 List *rlist,
1616                                                                 Plan *topplan,
1617                                                                 Index resultRelation)
1618 {
1619         indexed_tlist *itlist;
1620
1621         /*
1622          * We can perform the desired Var fixup by abusing the fix_join_expr
1623          * machinery that normally handles inner indexscan fixup.  We search the
1624          * top plan's targetlist for Vars of non-result relations, and use
1625          * fix_join_expr to convert RETURNING Vars into references to those tlist
1626          * entries, while leaving result-rel Vars as-is.
1627          *
1628          * PlaceHolderVars will also be sought in the targetlist, but no
1629          * more-complex expressions will be.  Note that it is not possible for
1630          * a PlaceHolderVar to refer to the result relation, since the result
1631          * is never below an outer join.  If that case could happen, we'd have
1632          * to be prepared to pick apart the PlaceHolderVar and evaluate its
1633          * contained expression instead.
1634          */
1635         itlist = build_tlist_index_other_vars(topplan->targetlist, resultRelation);
1636
1637         rlist = fix_join_expr(glob,
1638                                                   rlist,
1639                                                   itlist,
1640                                                   NULL,
1641                                                   resultRelation,
1642                                                   0);
1643
1644         pfree(itlist);
1645
1646         return rlist;
1647 }
1648
1649 /*****************************************************************************
1650  *                                      OPERATOR REGPROC LOOKUP
1651  *****************************************************************************/
1652
1653 /*
1654  * fix_opfuncids
1655  *        Calculate opfuncid field from opno for each OpExpr node in given tree.
1656  *        The given tree can be anything expression_tree_walker handles.
1657  *
1658  * The argument is modified in-place.  (This is OK since we'd want the
1659  * same change for any node, even if it gets visited more than once due to
1660  * shared structure.)
1661  */
1662 void
1663 fix_opfuncids(Node *node)
1664 {
1665         /* This tree walk requires no special setup, so away we go... */
1666         fix_opfuncids_walker(node, NULL);
1667 }
1668
1669 static bool
1670 fix_opfuncids_walker(Node *node, void *context)
1671 {
1672         if (node == NULL)
1673                 return false;
1674         if (IsA(node, OpExpr))
1675                 set_opfuncid((OpExpr *) node);
1676         else if (IsA(node, DistinctExpr))
1677                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1678         else if (IsA(node, NullIfExpr))
1679                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1680         else if (IsA(node, ScalarArrayOpExpr))
1681                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
1682         return expression_tree_walker(node, fix_opfuncids_walker, context);
1683 }
1684
1685 /*
1686  * set_opfuncid
1687  *              Set the opfuncid (procedure OID) in an OpExpr node,
1688  *              if it hasn't been set already.
1689  *
1690  * Because of struct equivalence, this can also be used for
1691  * DistinctExpr and NullIfExpr nodes.
1692  */
1693 void
1694 set_opfuncid(OpExpr *opexpr)
1695 {
1696         if (opexpr->opfuncid == InvalidOid)
1697                 opexpr->opfuncid = get_opcode(opexpr->opno);
1698 }
1699
1700 /*
1701  * set_sa_opfuncid
1702  *              As above, for ScalarArrayOpExpr nodes.
1703  */
1704 void
1705 set_sa_opfuncid(ScalarArrayOpExpr *opexpr)
1706 {
1707         if (opexpr->opfuncid == InvalidOid)
1708                 opexpr->opfuncid = get_opcode(opexpr->opno);
1709 }
1710
1711 /*****************************************************************************
1712  *                                      QUERY DEPENDENCY MANAGEMENT
1713  *****************************************************************************/
1714
1715 /*
1716  * record_plan_function_dependency
1717  *              Mark the current plan as depending on a particular function.
1718  *
1719  * This is exported so that the function-inlining code can record a
1720  * dependency on a function that it's removed from the plan tree.
1721  */
1722 void
1723 record_plan_function_dependency(PlannerGlobal *glob, Oid funcid)
1724 {
1725         /*
1726          * For performance reasons, we don't bother to track built-in functions;
1727          * we just assume they'll never change (or at least not in ways that'd
1728          * invalidate plans using them).  For this purpose we can consider a
1729          * built-in function to be one with OID less than FirstBootstrapObjectId.
1730          * Note that the OID generator guarantees never to generate such an
1731          * OID after startup, even at OID wraparound.
1732          */
1733         if (funcid >= (Oid) FirstBootstrapObjectId)
1734         {
1735                 HeapTuple       func_tuple;
1736                 PlanInvalItem *inval_item;
1737
1738                 func_tuple = SearchSysCache(PROCOID,
1739                                                                         ObjectIdGetDatum(funcid),
1740                                                                         0, 0, 0);
1741                 if (!HeapTupleIsValid(func_tuple))
1742                         elog(ERROR, "cache lookup failed for function %u", funcid);
1743
1744                 inval_item = makeNode(PlanInvalItem);
1745
1746                 /*
1747                  * It would work to use any syscache on pg_proc, but plancache.c
1748                  * expects us to use PROCOID.
1749                  */
1750                 inval_item->cacheId = PROCOID;
1751                 inval_item->tupleId = func_tuple->t_self;
1752
1753                 glob->invalItems = lappend(glob->invalItems, inval_item);
1754
1755                 ReleaseSysCache(func_tuple);
1756         }
1757 }
1758
1759 /*
1760  * extract_query_dependencies
1761  *              Given a list of not-yet-planned queries (i.e. Query nodes),
1762  *              extract their dependencies just as set_plan_references would do.
1763  *
1764  * This is needed by plancache.c to handle invalidation of cached unplanned
1765  * queries.
1766  */
1767 void
1768 extract_query_dependencies(List *queries,
1769                                                    List **relationOids,
1770                                                    List **invalItems)
1771 {
1772         PlannerGlobal glob;
1773
1774         /* Make up a dummy PlannerGlobal so we can use this module's machinery */
1775         MemSet(&glob, 0, sizeof(glob));
1776         glob.type = T_PlannerGlobal;
1777         glob.relationOids = NIL;
1778         glob.invalItems = NIL;
1779
1780         (void) extract_query_dependencies_walker((Node *) queries, &glob);
1781
1782         *relationOids = glob.relationOids;
1783         *invalItems = glob.invalItems;
1784 }
1785
1786 static bool
1787 extract_query_dependencies_walker(Node *node, PlannerGlobal *context)
1788 {
1789         if (node == NULL)
1790                 return false;
1791         Assert(!IsA(node, PlaceHolderVar));
1792         /* Extract function dependencies and check for regclass Consts */
1793         fix_expr_common(context, node);
1794         if (IsA(node, Query))
1795         {
1796                 Query      *query = (Query *) node;
1797                 ListCell   *lc;
1798
1799                 /* Collect relation OIDs in this Query's rtable */
1800                 foreach(lc, query->rtable)
1801                 {
1802                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
1803
1804                         if (rte->rtekind == RTE_RELATION)
1805                                 context->relationOids = lappend_oid(context->relationOids,
1806                                                                                                         rte->relid);
1807                 }
1808
1809                 /* And recurse into the query's subexpressions */
1810                 return query_tree_walker(query, extract_query_dependencies_walker,
1811                                                                  (void *) context, 0);
1812         }
1813         return expression_tree_walker(node, extract_query_dependencies_walker,
1814                                                                   (void *) context);
1815 }