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 1.144 2008/09/09 18:58:08 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_non_vars;   /* are there non-plain-Var entries? */
  42         /* array of num_vars entries: */
  43         tlist_vinfo vars[1];            /* VARIABLE LENGTH ARRAY */
  44 } indexed_tlist;                                /* VARIABLE LENGTH STRUCT */
  45
  46 typedef struct
  47 {
  48         PlannerGlobal *glob;
  49         int                     rtoffset;
  50 } fix_scan_expr_context;
  51
  52 typedef struct
  53 {
  54         PlannerGlobal *glob;
  55         indexed_tlist *outer_itlist;
  56         indexed_tlist *inner_itlist;
  57         Index           acceptable_rel;
  58         int                     rtoffset;
  59 } fix_join_expr_context;
  60
  61 typedef struct
  62 {
  63         PlannerGlobal *glob;
  64         indexed_tlist *subplan_itlist;
  65         int                     rtoffset;
  66 } fix_upper_expr_context;
  67
  68 /*
  69  * Check if a Const node is a regclass value.  We accept plain OID too,
  70  * since a regclass Const will get folded to that type if it's an argument
  71  * to oideq or similar operators.  (This might result in some extraneous
  72  * values in a plan's list of relation dependencies, but the worst result
  73  * would be occasional useless replans.)
  74  */
  75 #define ISREGCLASSCONST(con) \
  76         (((con)->consttype == REGCLASSOID || (con)->consttype == OIDOID) && \
  77          !(con)->constisnull)
  78
  79 #define fix_scan_list(glob, lst, rtoffset) \
  80         ((List *) fix_scan_expr(glob, (Node *) (lst), rtoffset))
  81
  82 static Plan *set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset);
  83 static Plan *set_subqueryscan_references(PlannerGlobal *glob,
  84                                                         SubqueryScan *plan,
  85                                                         int rtoffset);
  86 static bool trivial_subqueryscan(SubqueryScan *plan);
  87 static Node *fix_scan_expr(PlannerGlobal *glob, Node *node, int rtoffset);
  88 static Node *fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context);
  89 static bool fix_scan_expr_walker(Node *node, fix_scan_expr_context *context);
  90 static void set_join_references(PlannerGlobal *glob, Join *join, int rtoffset);
  91 static void set_inner_join_references(PlannerGlobal *glob, Plan *inner_plan,
  92                                                   indexed_tlist *outer_itlist);
  93 static void set_upper_references(PlannerGlobal *glob, Plan *plan, int rtoffset);
  94 static void set_dummy_tlist_references(Plan *plan, int rtoffset);
  95 static indexed_tlist *build_tlist_index(List *tlist);
  96 static Var *search_indexed_tlist_for_var(Var *var,
  97                                                          indexed_tlist *itlist,
  98                                                          Index newvarno,
  99                                                          int rtoffset);
 100 static Var *search_indexed_tlist_for_non_var(Node *node,
 101                                                                  indexed_tlist *itlist,
 102                                                                  Index newvarno);
 103 static List *fix_join_expr(PlannerGlobal *glob,
 104                           List *clauses,
 105                           indexed_tlist *outer_itlist,
 106                           indexed_tlist *inner_itlist,
 107                           Index acceptable_rel, int rtoffset);
 108 static Node *fix_join_expr_mutator(Node *node,
 109                                           fix_join_expr_context *context);
 110 static Node *fix_upper_expr(PlannerGlobal *glob,
 111                            Node *node,
 112                            indexed_tlist *subplan_itlist,
 113                            int rtoffset);
 114 static Node *fix_upper_expr_mutator(Node *node,
 115                                            fix_upper_expr_context *context);
 116 static bool fix_opfuncids_walker(Node *node, void *context);
 117 static bool extract_query_dependencies_walker(Node *node,
 118                                                                                           PlannerGlobal *context);
 119
 120
 121 /*****************************************************************************
 122  *
 123  *              SUBPLAN REFERENCES
 124  *
 125  *****************************************************************************/
 126
 127 /*
 128  * set_plan_references
 129  *
 130  * This is the final processing pass of the planner/optimizer.  The plan
 131  * tree is complete; we just have to adjust some representational details
 132  * for the convenience of the executor:
 133  *
 134  * 1. We flatten the various subquery rangetables into a single list, and
 135  * zero out RangeTblEntry fields that are not useful to the executor.
 136  *
 137  * 2. We adjust Vars in scan nodes to be consistent with the flat rangetable.
 138  *
 139  * 3. We adjust Vars in upper plan nodes to refer to the outputs of their
 140  * subplans.
 141  *
 142  * 4. We compute regproc OIDs for operators (ie, we look up the function
 143  * that implements each op).
 144  *
 145  * 5. We create lists of specific objects that the plan depends on.
 146  * This will be used by plancache.c to drive invalidation of cached plans.
 147  * Relation dependencies are represented by OIDs, and everything else by
 148  * PlanInvalItems (this distinction is motivated by the shared-inval APIs).
 149  * Currently, relations and user-defined functions are the only types of
 150  * objects that are explicitly tracked this way.
 151  *
 152  * We also perform one final optimization step, which is to delete
 153  * SubqueryScan plan nodes that aren't doing anything useful (ie, have
 154  * no qual and a no-op targetlist).  The reason for doing this last is that
 155  * it can't readily be done before set_plan_references, because it would
 156  * break set_upper_references: the Vars in the subquery's top tlist
 157  * wouldn't match up with the Vars in the outer plan tree.  The SubqueryScan
 158  * serves a necessary function as a buffer between outer query and subquery
 159  * variable numbering ... but after we've flattened the rangetable this is
 160  * no longer a problem, since then there's only one rtindex namespace.
 161  *
 162  * set_plan_references recursively traverses the whole plan tree.
 163  *
 164  * Inputs:
 165  *      glob: global data for planner run
 166  *      plan: the topmost node of the plan
 167  *      rtable: the rangetable for the current subquery
 168  *
 169  * The return value is normally the same Plan node passed in, but can be
 170  * different when the passed-in Plan is a SubqueryScan we decide isn't needed.
 171  *
 172  * The flattened rangetable entries are appended to glob->finalrtable, and
 173  * plan dependencies are appended to glob->relationOids (for relations)
 174  * and glob->invalItems (for everything else).
 175  *
 176  * Notice that we modify Plan nodes in-place, but use expression_tree_mutator
 177  * to process targetlist and qual expressions.  We can assume that the Plan
 178  * nodes were just built by the planner and are not multiply referenced, but
 179  * it's not so safe to assume that for expression tree nodes.
 180  */
 181 Plan *
 182 set_plan_references(PlannerGlobal *glob, Plan *plan, List *rtable)
 183 {
 184         int                     rtoffset = list_length(glob->finalrtable);
 185         ListCell   *lc;
 186
 187         /*
 188          * In the flat rangetable, we zero out substructure pointers that are not
 189          * needed by the executor; this reduces the storage space and copying cost
 190          * for cached plans.  We keep only the alias and eref Alias fields, which
 191          * are needed by EXPLAIN.
 192          */
 193         foreach(lc, rtable)
 194         {
 195                 RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
 196                 RangeTblEntry *newrte;
 197
 198                 /* flat copy to duplicate all the scalar fields */
 199                 newrte = (RangeTblEntry *) palloc(sizeof(RangeTblEntry));
 200                 memcpy(newrte, rte, sizeof(RangeTblEntry));
 201
 202                 /* zap unneeded sub-structure */
 203                 newrte->subquery = NULL;
 204                 newrte->funcexpr = NULL;
 205                 newrte->funccoltypes = NIL;
 206                 newrte->funccoltypmods = NIL;
 207                 newrte->values_lists = NIL;
 208                 newrte->joinaliasvars = NIL;
 209
 210                 glob->finalrtable = lappend(glob->finalrtable, newrte);
 211
 212                 /*
 213                  * If it's a plain relation RTE, add the table to relationOids.
 214                  *
 215                  * We do this even though the RTE might be unreferenced in the plan
 216                  * tree; this would correspond to cases such as views that were
 217                  * expanded, child tables that were eliminated by constraint
 218                  * exclusion, etc.      Schema invalidation on such a rel must still force
 219                  * rebuilding of the plan.
 220                  *
 221                  * Note we don't bother to avoid duplicate list entries.  We could,
 222                  * but it would probably cost more cycles than it would save.
 223                  */
 224                 if (newrte->rtekind == RTE_RELATION)
 225                         glob->relationOids = lappend_oid(glob->relationOids,
 226                                                                                          newrte->relid);
 227         }
 228
 229         /* Now fix the Plan tree */
 230         return set_plan_refs(glob, plan, rtoffset);
 231 }
 232
 233 /*
 234  * set_plan_refs: recurse through the Plan nodes of a single subquery level
 235  */
 236 static Plan *
 237 set_plan_refs(PlannerGlobal *glob, Plan *plan, int rtoffset)
 238 {
 239         ListCell   *l;
 240
 241         if (plan == NULL)
 242                 return NULL;
 243
 244         /*
 245          * Plan-type-specific fixes
 246          */
 247         switch (nodeTag(plan))
 248         {
 249                 case T_SeqScan:
 250                         {
 251                                 SeqScan    *splan = (SeqScan *) plan;
 252
 253                                 splan->scanrelid += rtoffset;
 254                                 splan->plan.targetlist =
 255                                         fix_scan_list(glob, splan->plan.targetlist, rtoffset);
 256                                 splan->plan.qual =
 257                                         fix_scan_list(glob, splan->plan.qual, rtoffset);
 258                         }
 259                         break;
 260                 case T_IndexScan:
 261                         {
 262                                 IndexScan  *splan = (IndexScan *) plan;
 263
 264                                 splan->scan.scanrelid += rtoffset;
 265                                 splan->scan.plan.targetlist =
 266                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 267                                 splan->scan.plan.qual =
 268                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 269                                 splan->indexqual =
 270                                         fix_scan_list(glob, splan->indexqual, rtoffset);
 271                                 splan->indexqualorig =
 272                                         fix_scan_list(glob, splan->indexqualorig, rtoffset);
 273                         }
 274                         break;
 275                 case T_BitmapIndexScan:
 276                         {
 277                                 BitmapIndexScan *splan = (BitmapIndexScan *) plan;
 278
 279                                 splan->scan.scanrelid += rtoffset;
 280                                 /* no need to fix targetlist and qual */
 281                                 Assert(splan->scan.plan.targetlist == NIL);
 282                                 Assert(splan->scan.plan.qual == NIL);
 283                                 splan->indexqual =
 284                                         fix_scan_list(glob, splan->indexqual, rtoffset);
 285                                 splan->indexqualorig =
 286                                         fix_scan_list(glob, splan->indexqualorig, rtoffset);
 287                         }
 288                         break;
 289                 case T_BitmapHeapScan:
 290                         {
 291                                 BitmapHeapScan *splan = (BitmapHeapScan *) plan;
 292
 293                                 splan->scan.scanrelid += rtoffset;
 294                                 splan->scan.plan.targetlist =
 295                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 296                                 splan->scan.plan.qual =
 297                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 298                                 splan->bitmapqualorig =
 299                                         fix_scan_list(glob, splan->bitmapqualorig, rtoffset);
 300                         }
 301                         break;
 302                 case T_TidScan:
 303                         {
 304                                 TidScan    *splan = (TidScan *) plan;
 305
 306                                 splan->scan.scanrelid += rtoffset;
 307                                 splan->scan.plan.targetlist =
 308                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 309                                 splan->scan.plan.qual =
 310                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 311                                 splan->tidquals =
 312                                         fix_scan_list(glob, splan->tidquals, rtoffset);
 313                         }
 314                         break;
 315                 case T_SubqueryScan:
 316                         /* Needs special treatment, see comments below */
 317                         return set_subqueryscan_references(glob,
 318                                                                                            (SubqueryScan *) plan,
 319                                                                                            rtoffset);
 320                 case T_FunctionScan:
 321                         {
 322                                 FunctionScan *splan = (FunctionScan *) plan;
 323
 324                                 splan->scan.scanrelid += rtoffset;
 325                                 splan->scan.plan.targetlist =
 326                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 327                                 splan->scan.plan.qual =
 328                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 329                                 splan->funcexpr =
 330                                         fix_scan_expr(glob, splan->funcexpr, rtoffset);
 331                         }
 332                         break;
 333                 case T_ValuesScan:
 334                         {
 335                                 ValuesScan *splan = (ValuesScan *) plan;
 336
 337                                 splan->scan.scanrelid += rtoffset;
 338                                 splan->scan.plan.targetlist =
 339                                         fix_scan_list(glob, splan->scan.plan.targetlist, rtoffset);
 340                                 splan->scan.plan.qual =
 341                                         fix_scan_list(glob, splan->scan.plan.qual, rtoffset);
 342                                 splan->values_lists =
 343                                         fix_scan_list(glob, splan->values_lists, rtoffset);
 344                         }
 345                         break;
 346
 347                 case T_NestLoop:
 348                 case T_MergeJoin:
 349                 case T_HashJoin:
 350                         set_join_references(glob, (Join *) plan, rtoffset);
 351                         break;
 352
 353                 case T_Hash:
 354                 case T_Material:
 355                 case T_Sort:
 356                 case T_Unique:
 357                 case T_SetOp:
 358
 359                         /*
 360                          * These plan types don't actually bother to evaluate their
 361                          * targetlists, because they just return their unmodified input
 362                          * tuples.      Even though the targetlist won't be used by the
 363                          * executor, we fix it up for possible use by EXPLAIN (not to
 364                          * mention ease of debugging --- wrong varnos are very confusing).
 365                          */
 366                         set_dummy_tlist_references(plan, rtoffset);
 367
 368                         /*
 369                          * Since these plan types don't check quals either, we should not
 370                          * find any qual expression attached to them.
 371                          */
 372                         Assert(plan->qual == NIL);
 373                         break;
 374                 case T_Limit:
 375                         {
 376                                 Limit      *splan = (Limit *) plan;
 377
 378                                 /*
 379                                  * Like the plan types above, Limit doesn't evaluate its tlist
 380                                  * or quals.  It does have live expressions for limit/offset,
 381                                  * however; and those cannot contain subplan variable refs, so
 382                                  * fix_scan_expr works for them.
 383                                  */
 384                                 set_dummy_tlist_references(plan, rtoffset);
 385                                 Assert(splan->plan.qual == NIL);
 386
 387                                 splan->limitOffset =
 388                                         fix_scan_expr(glob, splan->limitOffset, rtoffset);
 389                                 splan->limitCount =
 390                                         fix_scan_expr(glob, splan->limitCount, rtoffset);
 391                         }
 392                         break;
 393                 case T_Agg:
 394                 case T_Group:
 395                         set_upper_references(glob, plan, rtoffset);
 396                         break;
 397                 case T_Result:
 398                         {
 399                                 Result     *splan = (Result *) plan;
 400
 401                                 /*
 402                                  * Result may or may not have a subplan; if not, it's more
 403                                  * like a scan node than an upper node.
 404                                  */
 405                                 if (splan->plan.lefttree != NULL)
 406                                         set_upper_references(glob, plan, rtoffset);
 407                                 else
 408                                 {
 409                                         splan->plan.targetlist =
 410                                                 fix_scan_list(glob, splan->plan.targetlist, rtoffset);
 411                                         splan->plan.qual =
 412                                                 fix_scan_list(glob, splan->plan.qual, rtoffset);
 413                                 }
 414                                 /* resconstantqual can't contain any subplan variable refs */
 415                                 splan->resconstantqual =
 416                                         fix_scan_expr(glob, splan->resconstantqual, rtoffset);
 417                         }
 418                         break;
 419                 case T_Append:
 420                         {
 421                                 Append     *splan = (Append *) plan;
 422
 423                                 /*
 424                                  * Append, like Sort et al, doesn't actually evaluate its
 425                                  * targetlist or check quals.
 426                                  */
 427                                 set_dummy_tlist_references(plan, rtoffset);
 428                                 Assert(splan->plan.qual == NIL);
 429                                 foreach(l, splan->appendplans)
 430                                 {
 431                                         lfirst(l) = set_plan_refs(glob,
 432                                                                                           (Plan *) lfirst(l),
 433                                                                                           rtoffset);
 434                                 }
 435                         }
 436                         break;
 437                 case T_BitmapAnd:
 438                         {
 439                                 BitmapAnd  *splan = (BitmapAnd *) plan;
 440
 441                                 /* BitmapAnd works like Append, but has no tlist */
 442                                 Assert(splan->plan.targetlist == NIL);
 443                                 Assert(splan->plan.qual == NIL);
 444                                 foreach(l, splan->bitmapplans)
 445                                 {
 446                                         lfirst(l) = set_plan_refs(glob,
 447                                                                                           (Plan *) lfirst(l),
 448                                                                                           rtoffset);
 449                                 }
 450                         }
 451                         break;
 452                 case T_BitmapOr:
 453                         {
 454                                 BitmapOr   *splan = (BitmapOr *) plan;
 455
 456                                 /* BitmapOr works like Append, but has no tlist */
 457                                 Assert(splan->plan.targetlist == NIL);
 458                                 Assert(splan->plan.qual == NIL);
 459                                 foreach(l, splan->bitmapplans)
 460                                 {
 461                                         lfirst(l) = set_plan_refs(glob,
 462                                                                                           (Plan *) lfirst(l),
 463                                                                                           rtoffset);
 464                                 }
 465                         }
 466                         break;
 467                 default:
 468                         elog(ERROR, "unrecognized node type: %d",
 469                                  (int) nodeTag(plan));
 470                         break;
 471         }
 472
 473         /*
 474          * Now recurse into child plans, if any
 475          *
 476          * NOTE: it is essential that we recurse into child plans AFTER we set
 477          * subplan references in this plan's tlist and quals.  If we did the
 478          * reference-adjustments bottom-up, then we would fail to match this
 479          * plan's var nodes against the already-modified nodes of the children.
 480          */
 481         plan->lefttree = set_plan_refs(glob, plan->lefttree, rtoffset);
 482         plan->righttree = set_plan_refs(glob, plan->righttree, rtoffset);
 483
 484         return plan;
 485 }
 486
 487 /*
 488  * set_subqueryscan_references
 489  *              Do set_plan_references processing on a SubqueryScan
 490  *
 491  * We try to strip out the SubqueryScan entirely; if we can't, we have
 492  * to do the normal processing on it.
 493  */
 494 static Plan *
 495 set_subqueryscan_references(PlannerGlobal *glob,
 496                                                         SubqueryScan *plan,
 497                                                         int rtoffset)
 498 {
 499         Plan       *result;
 500
 501         /* First, recursively process the subplan */
 502         plan->subplan = set_plan_references(glob, plan->subplan, plan->subrtable);
 503
 504         /* subrtable is no longer needed in the plan tree */
 505         plan->subrtable = NIL;
 506
 507         if (trivial_subqueryscan(plan))
 508         {
 509                 /*
 510                  * We can omit the SubqueryScan node and just pull up the subplan.
 511                  */
 512                 ListCell   *lp,
 513                                    *lc;
 514
 515                 result = plan->subplan;
 516
 517                 /* We have to be sure we don't lose any initplans */
 518                 result->initPlan = list_concat(plan->scan.plan.initPlan,
 519                                                                            result->initPlan);
 520
 521                 /*
 522                  * We also have to transfer the SubqueryScan's result-column names
 523                  * into the subplan, else columns sent to client will be improperly
 524                  * labeled if this is the topmost plan level.  Copy the "source
 525                  * column" information too.
 526                  */
 527                 forboth(lp, plan->scan.plan.targetlist, lc, result->targetlist)
 528                 {
 529                         TargetEntry *ptle = (TargetEntry *) lfirst(lp);
 530                         TargetEntry *ctle = (TargetEntry *) lfirst(lc);
 531
 532                         ctle->resname = ptle->resname;
 533                         ctle->resorigtbl = ptle->resorigtbl;
 534                         ctle->resorigcol = ptle->resorigcol;
 535                 }
 536         }
 537         else
 538         {
 539                 /*
 540                  * Keep the SubqueryScan node.  We have to do the processing that
 541                  * set_plan_references would otherwise have done on it.  Notice we do
 542                  * not do set_upper_references() here, because a SubqueryScan will
 543                  * always have been created with correct references to its subplan's
 544                  * outputs to begin with.
 545                  */
 546                 plan->scan.scanrelid += rtoffset;
 547                 plan->scan.plan.targetlist =
 548                         fix_scan_list(glob, plan->scan.plan.targetlist, rtoffset);
 549                 plan->scan.plan.qual =
 550                         fix_scan_list(glob, plan->scan.plan.qual, rtoffset);
 551
 552                 result = (Plan *) plan;
 553         }
 554
 555         return result;
 556 }
 557
 558 /*
 559  * trivial_subqueryscan
 560  *              Detect whether a SubqueryScan can be deleted from the plan tree.
 561  *
 562  * We can delete it if it has no qual to check and the targetlist just
 563  * regurgitates the output of the child plan.
 564  */
 565 static bool
 566 trivial_subqueryscan(SubqueryScan *plan)
 567 {
 568         int                     attrno;
 569         ListCell   *lp,
 570                            *lc;
 571
 572         if (plan->scan.plan.qual != NIL)
 573                 return false;
 574
 575         if (list_length(plan->scan.plan.targetlist) !=
 576                 list_length(plan->subplan->targetlist))
 577                 return false;                   /* tlists not same length */
 578
 579         attrno = 1;
 580         forboth(lp, plan->scan.plan.targetlist, lc, plan->subplan->targetlist)
 581         {
 582                 TargetEntry *ptle = (TargetEntry *) lfirst(lp);
 583                 TargetEntry *ctle = (TargetEntry *) lfirst(lc);
 584
 585                 if (ptle->resjunk != ctle->resjunk)
 586                         return false;           /* tlist doesn't match junk status */
 587
 588                 /*
 589                  * We accept either a Var referencing the corresponding element of the
 590                  * subplan tlist, or a Const equaling the subplan element. See
 591                  * generate_setop_tlist() for motivation.
 592                  */
 593                 if (ptle->expr && IsA(ptle->expr, Var))
 594                 {
 595                         Var                *var = (Var *) ptle->expr;
 596
 597                         Assert(var->varno == plan->scan.scanrelid);
 598                         Assert(var->varlevelsup == 0);
 599                         if (var->varattno != attrno)
 600                                 return false;   /* out of order */
 601                 }
 602                 else if (ptle->expr && IsA(ptle->expr, Const))
 603                 {
 604                         if (!equal(ptle->expr, ctle->expr))
 605                                 return false;
 606                 }
 607                 else
 608                         return false;
 609
 610                 attrno++;
 611         }
 612
 613         return true;
 614 }
 615
 616 /*
 617  * copyVar
 618  *              Copy a Var node.
 619  *
 620  * fix_scan_expr and friends do this enough times that it's worth having
 621  * a bespoke routine instead of using the generic copyObject() function.
 622  */
 623 static inline Var *
 624 copyVar(Var *var)
 625 {
 626         Var                *newvar = (Var *) palloc(sizeof(Var));
 627
 628         *newvar = *var;
 629         return newvar;
 630 }
 631
 632 /*
 633  * fix_expr_common
 634  *              Do generic set_plan_references processing on an expression node
 635  *
 636  * This is code that is common to all variants of expression-fixing.
 637  * We must look up operator opcode info for OpExpr and related nodes,
 638  * add OIDs from regclass Const nodes into glob->relationOids,
 639  * and add catalog TIDs for user-defined functions into glob->invalItems.
 640  *
 641  * We assume it's okay to update opcode info in-place.  So this could possibly
 642  * scribble on the planner's input data structures, but it's OK.
 643  */
 644 static void
 645 fix_expr_common(PlannerGlobal *glob, Node *node)
 646 {
 647         /* We assume callers won't call us on a NULL pointer */
 648         if (IsA(node, Aggref))
 649         {
 650                 record_plan_function_dependency(glob,
 651                                                                                 ((Aggref *) node)->aggfnoid);
 652         }
 653         else if (IsA(node, FuncExpr))
 654         {
 655                 record_plan_function_dependency(glob,
 656                                                                                 ((FuncExpr *) node)->funcid);
 657         }
 658         else if (IsA(node, OpExpr))
 659         {
 660                 set_opfuncid((OpExpr *) node);
 661                 record_plan_function_dependency(glob,
 662                                                                                 ((OpExpr *) node)->opfuncid);
 663         }
 664         else if (IsA(node, DistinctExpr))
 665         {
 666                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
 667                 record_plan_function_dependency(glob,
 668                                                                                 ((DistinctExpr *) node)->opfuncid);
 669         }
 670         else if (IsA(node, NullIfExpr))
 671         {
 672                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
 673                 record_plan_function_dependency(glob,
 674                                                                                 ((NullIfExpr *) node)->opfuncid);
 675         }
 676         else if (IsA(node, ScalarArrayOpExpr))
 677         {
 678                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
 679                 record_plan_function_dependency(glob,
 680                                                                                 ((ScalarArrayOpExpr *) node)->opfuncid);
 681         }
 682         else if (IsA(node, ArrayCoerceExpr))
 683         {
 684                 if (OidIsValid(((ArrayCoerceExpr *) node)->elemfuncid))
 685                         record_plan_function_dependency(glob,
 686                                                                                         ((ArrayCoerceExpr *) node)->elemfuncid);
 687         }
 688         else if (IsA(node, Const))
 689         {
 690                 Const      *con = (Const *) node;
 691
 692                 /* Check for regclass reference */
 693                 if (ISREGCLASSCONST(con))
 694                         glob->relationOids =
 695                                 lappend_oid(glob->relationOids,
 696                                                         DatumGetObjectId(con->constvalue));
 697         }
 698 }
 699
 700 /*
 701  * fix_scan_expr
 702  *              Do set_plan_references processing on a scan-level expression
 703  *
 704  * This consists of incrementing all Vars' varnos by rtoffset,
 705  * looking up operator opcode info for OpExpr and related nodes,
 706  * and adding OIDs from regclass Const nodes into glob->relationOids.
 707  */
 708 static Node *
 709 fix_scan_expr(PlannerGlobal *glob, Node *node, int rtoffset)
 710 {
 711         fix_scan_expr_context context;
 712
 713         context.glob = glob;
 714         context.rtoffset = rtoffset;
 715
 716         if (rtoffset != 0)
 717         {
 718                 return fix_scan_expr_mutator(node, &context);
 719         }
 720         else
 721         {
 722                 /*
 723                  * If rtoffset == 0, we don't need to change any Vars, which makes
 724                  * it OK to just scribble on the input node tree instead of copying
 725                  * (since the only change, filling in any unset opfuncid fields,
 726                  * is harmless).  This saves just enough cycles to be noticeable on
 727                  * trivial queries.
 728                  */
 729                 (void) fix_scan_expr_walker(node, &context);
 730                 return node;
 731         }
 732 }
 733
 734 static Node *
 735 fix_scan_expr_mutator(Node *node, fix_scan_expr_context *context)
 736 {
 737         if (node == NULL)
 738                 return NULL;
 739         if (IsA(node, Var))
 740         {
 741                 Var                *var = copyVar((Var *) node);
 742
 743                 Assert(var->varlevelsup == 0);
 744
 745                 /*
 746                  * We should not see any Vars marked INNER, but in a nestloop inner
 747                  * scan there could be OUTER Vars.      Leave them alone.
 748                  */
 749                 Assert(var->varno != INNER);
 750                 if (var->varno > 0 && var->varno != OUTER)
 751                         var->varno += context->rtoffset;
 752                 if (var->varnoold > 0)
 753                         var->varnoold += context->rtoffset;
 754                 return (Node *) var;
 755         }
 756         if (IsA(node, CurrentOfExpr))
 757         {
 758                 CurrentOfExpr *cexpr = (CurrentOfExpr *) copyObject(node);
 759
 760                 Assert(cexpr->cvarno != INNER);
 761                 Assert(cexpr->cvarno != OUTER);
 762                 cexpr->cvarno += context->rtoffset;
 763                 return (Node *) cexpr;
 764         }
 765         fix_expr_common(context->glob, node);
 766         return expression_tree_mutator(node, fix_scan_expr_mutator,
 767                                                                    (void *) context);
 768 }
 769
 770 static bool
 771 fix_scan_expr_walker(Node *node, fix_scan_expr_context *context)
 772 {
 773         if (node == NULL)
 774                 return false;
 775         fix_expr_common(context->glob, node);
 776         return expression_tree_walker(node, fix_scan_expr_walker,
 777                                                                   (void *) context);
 778 }
 779
 780 /*
 781  * set_join_references
 782  *        Modify the target list and quals of a join node to reference its
 783  *        subplans, by setting the varnos to OUTER or INNER and setting attno
 784  *        values to the result domain number of either the corresponding outer
 785  *        or inner join tuple item.  Also perform opcode lookup for these
 786  *        expressions. and add regclass OIDs to glob->relationOids.
 787  *
 788  * In the case of a nestloop with inner indexscan, we will also need to
 789  * apply the same transformation to any outer vars appearing in the
 790  * quals of the child indexscan.  set_inner_join_references does that.
 791  */
 792 static void
 793 set_join_references(PlannerGlobal *glob, Join *join, int rtoffset)
 794 {
 795         Plan       *outer_plan = join->plan.lefttree;
 796         Plan       *inner_plan = join->plan.righttree;
 797         indexed_tlist *outer_itlist;
 798         indexed_tlist *inner_itlist;
 799
 800         outer_itlist = build_tlist_index(outer_plan->targetlist);
 801         inner_itlist = build_tlist_index(inner_plan->targetlist);
 802
 803         /* All join plans have tlist, qual, and joinqual */
 804         join->plan.targetlist = fix_join_expr(glob,
 805                                                                                   join->plan.targetlist,
 806                                                                                   outer_itlist,
 807                                                                                   inner_itlist,
 808                                                                                   (Index) 0,
 809                                                                                   rtoffset);
 810         join->plan.qual = fix_join_expr(glob,
 811                                                                         join->plan.qual,
 812                                                                         outer_itlist,
 813                                                                         inner_itlist,
 814                                                                         (Index) 0,
 815                                                                         rtoffset);
 816         join->joinqual = fix_join_expr(glob,
 817                                                                    join->joinqual,
 818                                                                    outer_itlist,
 819                                                                    inner_itlist,
 820                                                                    (Index) 0,
 821                                                                    rtoffset);
 822
 823         /* Now do join-type-specific stuff */
 824         if (IsA(join, NestLoop))
 825         {
 826                 /* This processing is split out to handle possible recursion */
 827                 set_inner_join_references(glob, inner_plan, outer_itlist);
 828         }
 829         else if (IsA(join, MergeJoin))
 830         {
 831                 MergeJoin  *mj = (MergeJoin *) join;
 832
 833                 mj->mergeclauses = fix_join_expr(glob,
 834                                                                                  mj->mergeclauses,
 835                                                                                  outer_itlist,
 836                                                                                  inner_itlist,
 837                                                                                  (Index) 0,
 838                                                                                  rtoffset);
 839         }
 840         else if (IsA(join, HashJoin))
 841         {
 842                 HashJoin   *hj = (HashJoin *) join;
 843
 844                 hj->hashclauses = fix_join_expr(glob,
 845                                                                                 hj->hashclauses,
 846                                                                                 outer_itlist,
 847                                                                                 inner_itlist,
 848                                                                                 (Index) 0,
 849                                                                                 rtoffset);
 850         }
 851
 852         pfree(outer_itlist);
 853         pfree(inner_itlist);
 854 }
 855
 856 /*
 857  * set_inner_join_references
 858  *              Handle join references appearing in an inner indexscan's quals
 859  *
 860  * To handle bitmap-scan plan trees, we have to be able to recurse down
 861  * to the bottom BitmapIndexScan nodes; likewise, appendrel indexscans
 862  * require recursing through Append nodes.      This is split out as a separate
 863  * function so that it can recurse.
 864  *
 865  * Note we do *not* apply any rtoffset for non-join Vars; this is because
 866  * the quals will be processed again by fix_scan_expr when the set_plan_refs
 867  * recursion reaches the inner indexscan, and so we'd have done it twice.
 868  */
 869 static void
 870 set_inner_join_references(PlannerGlobal *glob, Plan *inner_plan,
 871                                                   indexed_tlist *outer_itlist)
 872 {
 873         if (IsA(inner_plan, IndexScan))
 874         {
 875                 /*
 876                  * An index is being used to reduce the number of tuples scanned in
 877                  * the inner relation.  If there are join clauses being used with the
 878                  * index, we must update their outer-rel var nodes to refer to the
 879                  * outer side of the join.
 880                  */
 881                 IndexScan  *innerscan = (IndexScan *) inner_plan;
 882                 List       *indexqualorig = innerscan->indexqualorig;
 883
 884                 /* No work needed if indexqual refers only to its own rel... */
 885                 if (NumRelids((Node *) indexqualorig) > 1)
 886                 {
 887                         Index           innerrel = innerscan->scan.scanrelid;
 888
 889                         /* only refs to outer vars get changed in the inner qual */
 890                         innerscan->indexqualorig = fix_join_expr(glob,
 891                                                                                                          indexqualorig,
 892                                                                                                          outer_itlist,
 893                                                                                                          NULL,
 894                                                                                                          innerrel,
 895                                                                                                          0);
 896                         innerscan->indexqual = fix_join_expr(glob,
 897                                                                                                  innerscan->indexqual,
 898                                                                                                  outer_itlist,
 899                                                                                                  NULL,
 900                                                                                                  innerrel,
 901                                                                                                  0);
 902
 903                         /*
 904                          * We must fix the inner qpqual too, if it has join clauses (this
 905                          * could happen if special operators are involved: some indexquals
 906                          * may get rechecked as qpquals).
 907                          */
 908                         if (NumRelids((Node *) inner_plan->qual) > 1)
 909                                 inner_plan->qual = fix_join_expr(glob,
 910                                                                                                  inner_plan->qual,
 911                                                                                                  outer_itlist,
 912                                                                                                  NULL,
 913                                                                                                  innerrel,
 914                                                                                                  0);
 915                 }
 916         }
 917         else if (IsA(inner_plan, BitmapIndexScan))
 918         {
 919                 /*
 920                  * Same, but index is being used within a bitmap plan.
 921                  */
 922                 BitmapIndexScan *innerscan = (BitmapIndexScan *) inner_plan;
 923                 List       *indexqualorig = innerscan->indexqualorig;
 924
 925                 /* No work needed if indexqual refers only to its own rel... */
 926                 if (NumRelids((Node *) indexqualorig) > 1)
 927                 {
 928                         Index           innerrel = innerscan->scan.scanrelid;
 929
 930                         /* only refs to outer vars get changed in the inner qual */
 931                         innerscan->indexqualorig = fix_join_expr(glob,
 932                                                                                                          indexqualorig,
 933                                                                                                          outer_itlist,
 934                                                                                                          NULL,
 935                                                                                                          innerrel,
 936                                                                                                          0);
 937                         innerscan->indexqual = fix_join_expr(glob,
 938                                                                                                  innerscan->indexqual,
 939                                                                                                  outer_itlist,
 940                                                                                                  NULL,
 941                                                                                                  innerrel,
 942                                                                                                  0);
 943                         /* no need to fix inner qpqual */
 944                         Assert(inner_plan->qual == NIL);
 945                 }
 946         }
 947         else if (IsA(inner_plan, BitmapHeapScan))
 948         {
 949                 /*
 950                  * The inner side is a bitmap scan plan.  Fix the top node, and
 951                  * recurse to get the lower nodes.
 952                  *
 953                  * Note: create_bitmap_scan_plan removes clauses from bitmapqualorig
 954                  * if they are duplicated in qpqual, so must test these independently.
 955                  */
 956                 BitmapHeapScan *innerscan = (BitmapHeapScan *) inner_plan;
 957                 Index           innerrel = innerscan->scan.scanrelid;
 958                 List       *bitmapqualorig = innerscan->bitmapqualorig;
 959
 960                 /* only refs to outer vars get changed in the inner qual */
 961                 if (NumRelids((Node *) bitmapqualorig) > 1)
 962                         innerscan->bitmapqualorig = fix_join_expr(glob,
 963                                                                                                           bitmapqualorig,
 964                                                                                                           outer_itlist,
 965                                                                                                           NULL,
 966                                                                                                           innerrel,
 967                                                                                                           0);
 968
 969                 /*
 970                  * We must fix the inner qpqual too, if it has join clauses (this
 971                  * could happen if special operators are involved: some indexquals may
 972                  * get rechecked as qpquals).
 973                  */
 974                 if (NumRelids((Node *) inner_plan->qual) > 1)
 975                         inner_plan->qual = fix_join_expr(glob,
 976                                                                                          inner_plan->qual,
 977                                                                                          outer_itlist,
 978                                                                                          NULL,
 979                                                                                          innerrel,
 980                                                                                          0);
 981
 982                 /* Now recurse */
 983                 set_inner_join_references(glob, inner_plan->lefttree, outer_itlist);
 984         }
 985         else if (IsA(inner_plan, BitmapAnd))
 986         {
 987                 /* All we need do here is recurse */
 988                 BitmapAnd  *innerscan = (BitmapAnd *) inner_plan;
 989                 ListCell   *l;
 990
 991                 foreach(l, innerscan->bitmapplans)
 992                 {
 993                         set_inner_join_references(glob, (Plan *) lfirst(l), outer_itlist);
 994                 }
 995         }
 996         else if (IsA(inner_plan, BitmapOr))
 997         {
 998                 /* All we need do here is recurse */
 999                 BitmapOr   *innerscan = (BitmapOr *) inner_plan;
1000                 ListCell   *l;
1001
1002                 foreach(l, innerscan->bitmapplans)
1003                 {
1004                         set_inner_join_references(glob, (Plan *) lfirst(l), outer_itlist);
1005                 }
1006         }
1007         else if (IsA(inner_plan, TidScan))
1008         {
1009                 TidScan    *innerscan = (TidScan *) inner_plan;
1010                 Index           innerrel = innerscan->scan.scanrelid;
1011
1012                 innerscan->tidquals = fix_join_expr(glob,
1013                                                                                         innerscan->tidquals,
1014                                                                                         outer_itlist,
1015                                                                                         NULL,
1016                                                                                         innerrel,
1017                                                                                         0);
1018         }
1019         else if (IsA(inner_plan, Append))
1020         {
1021                 /*
1022                  * The inner side is an append plan.  Recurse to see if it contains
1023                  * indexscans that need to be fixed.
1024                  */
1025                 Append     *appendplan = (Append *) inner_plan;
1026                 ListCell   *l;
1027
1028                 foreach(l, appendplan->appendplans)
1029                 {
1030                         set_inner_join_references(glob, (Plan *) lfirst(l), outer_itlist);
1031                 }
1032         }
1033         else if (IsA(inner_plan, Result))
1034         {
1035                 /* Recurse through a gating Result node (similar to Append case) */
1036                 Result     *result = (Result *) inner_plan;
1037
1038                 if (result->plan.lefttree)
1039                         set_inner_join_references(glob, result->plan.lefttree, outer_itlist);
1040         }
1041 }
1042
1043 /*
1044  * set_upper_references
1045  *        Update the targetlist and quals of an upper-level plan node
1046  *        to refer to the tuples returned by its lefttree subplan.
1047  *        Also perform opcode lookup for these expressions, and
1048  *        add regclass OIDs to glob->relationOids.
1049  *
1050  * This is used for single-input plan types like Agg, Group, Result.
1051  *
1052  * In most cases, we have to match up individual Vars in the tlist and
1053  * qual expressions with elements of the subplan's tlist (which was
1054  * generated by flatten_tlist() from these selfsame expressions, so it
1055  * should have all the required variables).  There is an important exception,
1056  * however: GROUP BY and ORDER BY expressions will have been pushed into the
1057  * subplan tlist unflattened.  If these values are also needed in the output
1058  * then we want to reference the subplan tlist element rather than recomputing
1059  * the expression.
1060  */
1061 static void
1062 set_upper_references(PlannerGlobal *glob, Plan *plan, int rtoffset)
1063 {
1064         Plan       *subplan = plan->lefttree;
1065         indexed_tlist *subplan_itlist;
1066         List       *output_targetlist;
1067         ListCell   *l;
1068
1069         subplan_itlist = build_tlist_index(subplan->targetlist);
1070
1071         output_targetlist = NIL;
1072         foreach(l, plan->targetlist)
1073         {
1074                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1075                 Node       *newexpr;
1076
1077                 newexpr = fix_upper_expr(glob,
1078                                                                  (Node *) tle->expr,
1079                                                                  subplan_itlist,
1080                                                                  rtoffset);
1081                 tle = flatCopyTargetEntry(tle);
1082                 tle->expr = (Expr *) newexpr;
1083                 output_targetlist = lappend(output_targetlist, tle);
1084         }
1085         plan->targetlist = output_targetlist;
1086
1087         plan->qual = (List *)
1088                 fix_upper_expr(glob,
1089                                            (Node *) plan->qual,
1090                                            subplan_itlist,
1091                                            rtoffset);
1092
1093         pfree(subplan_itlist);
1094 }
1095
1096 /*
1097  * set_dummy_tlist_references
1098  *        Replace the targetlist of an upper-level plan node with a simple
1099  *        list of OUTER references to its child.
1100  *
1101  * This is used for plan types like Sort and Append that don't evaluate
1102  * their targetlists.  Although the executor doesn't care at all what's in
1103  * the tlist, EXPLAIN needs it to be realistic.
1104  *
1105  * Note: we could almost use set_upper_references() here, but it fails for
1106  * Append for lack of a lefttree subplan.  Single-purpose code is faster
1107  * anyway.
1108  */
1109 static void
1110 set_dummy_tlist_references(Plan *plan, int rtoffset)
1111 {
1112         List       *output_targetlist;
1113         ListCell   *l;
1114
1115         output_targetlist = NIL;
1116         foreach(l, plan->targetlist)
1117         {
1118                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1119                 Var                *oldvar = (Var *) tle->expr;
1120                 Var                *newvar;
1121
1122                 newvar = makeVar(OUTER,
1123                                                  tle->resno,
1124                                                  exprType((Node *) oldvar),
1125                                                  exprTypmod((Node *) oldvar),
1126                                                  0);
1127                 if (IsA(oldvar, Var))
1128                 {
1129                         newvar->varnoold = oldvar->varno + rtoffset;
1130                         newvar->varoattno = oldvar->varattno;
1131                 }
1132                 else
1133                 {
1134                         newvar->varnoold = 0;           /* wasn't ever a plain Var */
1135                         newvar->varoattno = 0;
1136                 }
1137
1138                 tle = flatCopyTargetEntry(tle);
1139                 tle->expr = (Expr *) newvar;
1140                 output_targetlist = lappend(output_targetlist, tle);
1141         }
1142         plan->targetlist = output_targetlist;
1143
1144         /* We don't touch plan->qual here */
1145 }
1146
1147
1148 /*
1149  * build_tlist_index --- build an index data structure for a child tlist
1150  *
1151  * In most cases, subplan tlists will be "flat" tlists with only Vars,
1152  * so we try to optimize that case by extracting information about Vars
1153  * in advance.  Matching a parent tlist to a child is still an O(N^2)
1154  * operation, but at least with a much smaller constant factor than plain
1155  * tlist_member() searches.
1156  *
1157  * The result of this function is an indexed_tlist struct to pass to
1158  * search_indexed_tlist_for_var() or search_indexed_tlist_for_non_var().
1159  * When done, the indexed_tlist may be freed with a single pfree().
1160  */
1161 static indexed_tlist *
1162 build_tlist_index(List *tlist)
1163 {
1164         indexed_tlist *itlist;
1165         tlist_vinfo *vinfo;
1166         ListCell   *l;
1167
1168         /* Create data structure with enough slots for all tlist entries */
1169         itlist = (indexed_tlist *)
1170                 palloc(offsetof(indexed_tlist, vars) +
1171                            list_length(tlist) * sizeof(tlist_vinfo));
1172
1173         itlist->tlist = tlist;
1174         itlist->has_non_vars = false;
1175
1176         /* Find the Vars and fill in the index array */
1177         vinfo = itlist->vars;
1178         foreach(l, tlist)
1179         {
1180                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1181
1182                 if (tle->expr && IsA(tle->expr, Var))
1183                 {
1184                         Var                *var = (Var *) tle->expr;
1185
1186                         vinfo->varno = var->varno;
1187                         vinfo->varattno = var->varattno;
1188                         vinfo->resno = tle->resno;
1189                         vinfo++;
1190                 }
1191                 else
1192                         itlist->has_non_vars = true;
1193         }
1194
1195         itlist->num_vars = (vinfo - itlist->vars);
1196
1197         return itlist;
1198 }
1199
1200 /*
1201  * build_tlist_index_other_vars --- build a restricted tlist index
1202  *
1203  * This is like build_tlist_index, but we only index tlist entries that
1204  * are Vars and belong to some rel other than the one specified.
1205  */
1206 static indexed_tlist *
1207 build_tlist_index_other_vars(List *tlist, Index ignore_rel)
1208 {
1209         indexed_tlist *itlist;
1210         tlist_vinfo *vinfo;
1211         ListCell   *l;
1212
1213         /* Create data structure with enough slots for all tlist entries */
1214         itlist = (indexed_tlist *)
1215                 palloc(offsetof(indexed_tlist, vars) +
1216                            list_length(tlist) * sizeof(tlist_vinfo));
1217
1218         itlist->tlist = tlist;
1219         itlist->has_non_vars = false;
1220
1221         /* Find the desired Vars and fill in the index array */
1222         vinfo = itlist->vars;
1223         foreach(l, tlist)
1224         {
1225                 TargetEntry *tle = (TargetEntry *) lfirst(l);
1226
1227                 if (tle->expr && IsA(tle->expr, Var))
1228                 {
1229                         Var                *var = (Var *) tle->expr;
1230
1231                         if (var->varno != ignore_rel)
1232                         {
1233                                 vinfo->varno = var->varno;
1234                                 vinfo->varattno = var->varattno;
1235                                 vinfo->resno = tle->resno;
1236                                 vinfo++;
1237                         }
1238                 }
1239         }
1240
1241         itlist->num_vars = (vinfo - itlist->vars);
1242
1243         return itlist;
1244 }
1245
1246 /*
1247  * search_indexed_tlist_for_var --- find a Var in an indexed tlist
1248  *
1249  * If a match is found, return a copy of the given Var with suitably
1250  * modified varno/varattno (to wit, newvarno and the resno of the TLE entry).
1251  * Also ensure that varnoold is incremented by rtoffset.
1252  * If no match, return NULL.
1253  */
1254 static Var *
1255 search_indexed_tlist_for_var(Var *var, indexed_tlist *itlist,
1256                                                          Index newvarno, int rtoffset)
1257 {
1258         Index           varno = var->varno;
1259         AttrNumber      varattno = var->varattno;
1260         tlist_vinfo *vinfo;
1261         int                     i;
1262
1263         vinfo = itlist->vars;
1264         i = itlist->num_vars;
1265         while (i-- > 0)
1266         {
1267                 if (vinfo->varno == varno && vinfo->varattno == varattno)
1268                 {
1269                         /* Found a match */
1270                         Var                *newvar = copyVar(var);
1271
1272                         newvar->varno = newvarno;
1273                         newvar->varattno = vinfo->resno;
1274                         if (newvar->varnoold > 0)
1275                                 newvar->varnoold += rtoffset;
1276                         return newvar;
1277                 }
1278                 vinfo++;
1279         }
1280         return NULL;                            /* no match */
1281 }
1282
1283 /*
1284  * search_indexed_tlist_for_non_var --- find a non-Var in an indexed tlist
1285  *
1286  * If a match is found, return a Var constructed to reference the tlist item.
1287  * If no match, return NULL.
1288  *
1289  * NOTE: it is a waste of time to call this if !itlist->has_non_vars
1290  */
1291 static Var *
1292 search_indexed_tlist_for_non_var(Node *node,
1293                                                                  indexed_tlist *itlist, Index newvarno)
1294 {
1295         TargetEntry *tle;
1296
1297         tle = tlist_member(node, itlist->tlist);
1298         if (tle)
1299         {
1300                 /* Found a matching subplan output expression */
1301                 Var                *newvar;
1302
1303                 newvar = makeVar(newvarno,
1304                                                  tle->resno,
1305                                                  exprType((Node *) tle->expr),
1306                                                  exprTypmod((Node *) tle->expr),
1307                                                  0);
1308                 newvar->varnoold = 0;   /* wasn't ever a plain Var */
1309                 newvar->varoattno = 0;
1310                 return newvar;
1311         }
1312         return NULL;                            /* no match */
1313 }
1314
1315 /*
1316  * fix_join_expr
1317  *         Create a new set of targetlist entries or join qual clauses by
1318  *         changing the varno/varattno values of variables in the clauses
1319  *         to reference target list values from the outer and inner join
1320  *         relation target lists.  Also perform opcode lookup and add
1321  *         regclass OIDs to glob->relationOids.
1322  *
1323  * This is used in two different scenarios: a normal join clause, where
1324  * all the Vars in the clause *must* be replaced by OUTER or INNER references;
1325  * and an indexscan being used on the inner side of a nestloop join.
1326  * In the latter case we want to replace the outer-relation Vars by OUTER
1327  * references, while Vars of the inner relation should be adjusted by rtoffset.
1328  * (We also implement RETURNING clause fixup using this second scenario.)
1329  *
1330  * For a normal join, acceptable_rel should be zero so that any failure to
1331  * match a Var will be reported as an error.  For the indexscan case,
1332  * pass inner_itlist = NULL and acceptable_rel = the (not-offseted-yet) ID
1333  * of the inner relation.
1334  *
1335  * 'clauses' is the targetlist or list of join clauses
1336  * 'outer_itlist' is the indexed target list of the outer join relation
1337  * 'inner_itlist' is the indexed target list of the inner join relation,
1338  *              or NULL
1339  * 'acceptable_rel' is either zero or the rangetable index of a relation
1340  *              whose Vars may appear in the clause without provoking an error.
1341  * 'rtoffset' is what to add to varno for Vars of acceptable_rel.
1342  *
1343  * Returns the new expression tree.  The original clause structure is
1344  * not modified.
1345  */
1346 static List *
1347 fix_join_expr(PlannerGlobal *glob,
1348                           List *clauses,
1349                           indexed_tlist *outer_itlist,
1350                           indexed_tlist *inner_itlist,
1351                           Index acceptable_rel,
1352                           int rtoffset)
1353 {
1354         fix_join_expr_context context;
1355
1356         context.glob = glob;
1357         context.outer_itlist = outer_itlist;
1358         context.inner_itlist = inner_itlist;
1359         context.acceptable_rel = acceptable_rel;
1360         context.rtoffset = rtoffset;
1361         return (List *) fix_join_expr_mutator((Node *) clauses, &context);
1362 }
1363
1364 static Node *
1365 fix_join_expr_mutator(Node *node, fix_join_expr_context *context)
1366 {
1367         Var                *newvar;
1368
1369         if (node == NULL)
1370                 return NULL;
1371         if (IsA(node, Var))
1372         {
1373                 Var                *var = (Var *) node;
1374
1375                 /* First look for the var in the input tlists */
1376                 newvar = search_indexed_tlist_for_var(var,
1377                                                                                           context->outer_itlist,
1378                                                                                           OUTER,
1379                                                                                           context->rtoffset);
1380                 if (newvar)
1381                         return (Node *) newvar;
1382                 if (context->inner_itlist)
1383                 {
1384                         newvar = search_indexed_tlist_for_var(var,
1385                                                                                                   context->inner_itlist,
1386                                                                                                   INNER,
1387                                                                                                   context->rtoffset);
1388                         if (newvar)
1389                                 return (Node *) newvar;
1390                 }
1391
1392                 /* If it's for acceptable_rel, adjust and return it */
1393                 if (var->varno == context->acceptable_rel)
1394                 {
1395                         var = copyVar(var);
1396                         var->varno += context->rtoffset;
1397                         var->varnoold += context->rtoffset;
1398                         return (Node *) var;
1399                 }
1400
1401                 /* No referent found for Var */
1402                 elog(ERROR, "variable not found in subplan target lists");
1403         }
1404         /* Try matching more complex expressions too, if tlists have any */
1405         if (context->outer_itlist->has_non_vars)
1406         {
1407                 newvar = search_indexed_tlist_for_non_var(node,
1408                                                                                                   context->outer_itlist,
1409                                                                                                   OUTER);
1410                 if (newvar)
1411                         return (Node *) newvar;
1412         }
1413         if (context->inner_itlist && context->inner_itlist->has_non_vars)
1414         {
1415                 newvar = search_indexed_tlist_for_non_var(node,
1416                                                                                                   context->inner_itlist,
1417                                                                                                   INNER);
1418                 if (newvar)
1419                         return (Node *) newvar;
1420         }
1421         fix_expr_common(context->glob, node);
1422         return expression_tree_mutator(node,
1423                                                                    fix_join_expr_mutator,
1424                                                                    (void *) context);
1425 }
1426
1427 /*
1428  * fix_upper_expr
1429  *              Modifies an expression tree so that all Var nodes reference outputs
1430  *              of a subplan.  Also performs opcode lookup, and adds regclass OIDs to
1431  *              glob->relationOids.
1432  *
1433  * This is used to fix up target and qual expressions of non-join upper-level
1434  * plan nodes.
1435  *
1436  * An error is raised if no matching var can be found in the subplan tlist
1437  * --- so this routine should only be applied to nodes whose subplans'
1438  * targetlists were generated via flatten_tlist() or some such method.
1439  *
1440  * If itlist->has_non_vars is true, then we try to match whole subexpressions
1441  * against elements of the subplan tlist, so that we can avoid recomputing
1442  * expressions that were already computed by the subplan.  (This is relatively
1443  * expensive, so we don't want to try it in the common case where the
1444  * subplan tlist is just a flattened list of Vars.)
1445  *
1446  * 'node': the tree to be fixed (a target item or qual)
1447  * 'subplan_itlist': indexed target list for subplan
1448  * 'rtoffset': how much to increment varnoold by
1449  *
1450  * The resulting tree is a copy of the original in which all Var nodes have
1451  * varno = OUTER, varattno = resno of corresponding subplan target.
1452  * The original tree is not modified.
1453  */
1454 static Node *
1455 fix_upper_expr(PlannerGlobal *glob,
1456                            Node *node,
1457                            indexed_tlist *subplan_itlist,
1458                            int rtoffset)
1459 {
1460         fix_upper_expr_context context;
1461
1462         context.glob = glob;
1463         context.subplan_itlist = subplan_itlist;
1464         context.rtoffset = rtoffset;
1465         return fix_upper_expr_mutator(node, &context);
1466 }
1467
1468 static Node *
1469 fix_upper_expr_mutator(Node *node, fix_upper_expr_context *context)
1470 {
1471         Var                *newvar;
1472
1473         if (node == NULL)
1474                 return NULL;
1475         if (IsA(node, Var))
1476         {
1477                 Var                *var = (Var *) node;
1478
1479                 newvar = search_indexed_tlist_for_var(var,
1480                                                                                           context->subplan_itlist,
1481                                                                                           OUTER,
1482                                                                                           context->rtoffset);
1483                 if (!newvar)
1484                         elog(ERROR, "variable not found in subplan target list");
1485                 return (Node *) newvar;
1486         }
1487         /* Try matching more complex expressions too, if tlist has any */
1488         if (context->subplan_itlist->has_non_vars)
1489         {
1490                 newvar = search_indexed_tlist_for_non_var(node,
1491                                                                                                   context->subplan_itlist,
1492                                                                                                   OUTER);
1493                 if (newvar)
1494                         return (Node *) newvar;
1495         }
1496         fix_expr_common(context->glob, node);
1497         return expression_tree_mutator(node,
1498                                                                    fix_upper_expr_mutator,
1499                                                                    (void *) context);
1500 }
1501
1502 /*
1503  * set_returning_clause_references
1504  *              Perform setrefs.c's work on a RETURNING targetlist
1505  *
1506  * If the query involves more than just the result table, we have to
1507  * adjust any Vars that refer to other tables to reference junk tlist
1508  * entries in the top plan's targetlist.  Vars referencing the result
1509  * table should be left alone, however (the executor will evaluate them
1510  * using the actual heap tuple, after firing triggers if any).  In the
1511  * adjusted RETURNING list, result-table Vars will still have their
1512  * original varno, but Vars for other rels will have varno OUTER.
1513  *
1514  * We also must perform opcode lookup and add regclass OIDs to
1515  * glob->relationOids.
1516  *
1517  * 'rlist': the RETURNING targetlist to be fixed
1518  * 'topplan': the top Plan node for the query (not yet passed through
1519  *              set_plan_references)
1520  * 'resultRelation': RT index of the associated result relation
1521  *
1522  * Note: we assume that result relations will have rtoffset zero, that is,
1523  * they are not coming from a subplan.
1524  */
1525 List *
1526 set_returning_clause_references(PlannerGlobal *glob,
1527                                                                 List *rlist,
1528                                                                 Plan *topplan,
1529                                                                 Index resultRelation)
1530 {
1531         indexed_tlist *itlist;
1532
1533         /*
1534          * We can perform the desired Var fixup by abusing the fix_join_expr
1535          * machinery that normally handles inner indexscan fixup.  We search the
1536          * top plan's targetlist for Vars of non-result relations, and use
1537          * fix_join_expr to convert RETURNING Vars into references to those tlist
1538          * entries, while leaving result-rel Vars as-is.
1539          */
1540         itlist = build_tlist_index_other_vars(topplan->targetlist, resultRelation);
1541
1542         rlist = fix_join_expr(glob,
1543                                                   rlist,
1544                                                   itlist,
1545                                                   NULL,
1546                                                   resultRelation,
1547                                                   0);
1548
1549         pfree(itlist);
1550
1551         return rlist;
1552 }
1553
1554 /*****************************************************************************
1555  *                                      OPERATOR REGPROC LOOKUP
1556  *****************************************************************************/
1557
1558 /*
1559  * fix_opfuncids
1560  *        Calculate opfuncid field from opno for each OpExpr node in given tree.
1561  *        The given tree can be anything expression_tree_walker handles.
1562  *
1563  * The argument is modified in-place.  (This is OK since we'd want the
1564  * same change for any node, even if it gets visited more than once due to
1565  * shared structure.)
1566  */
1567 void
1568 fix_opfuncids(Node *node)
1569 {
1570         /* This tree walk requires no special setup, so away we go... */
1571         fix_opfuncids_walker(node, NULL);
1572 }
1573
1574 static bool
1575 fix_opfuncids_walker(Node *node, void *context)
1576 {
1577         if (node == NULL)
1578                 return false;
1579         if (IsA(node, OpExpr))
1580                 set_opfuncid((OpExpr *) node);
1581         else if (IsA(node, DistinctExpr))
1582                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1583         else if (IsA(node, NullIfExpr))
1584                 set_opfuncid((OpExpr *) node);  /* rely on struct equivalence */
1585         else if (IsA(node, ScalarArrayOpExpr))
1586                 set_sa_opfuncid((ScalarArrayOpExpr *) node);
1587         return expression_tree_walker(node, fix_opfuncids_walker, context);
1588 }
1589
1590 /*
1591  * set_opfuncid
1592  *              Set the opfuncid (procedure OID) in an OpExpr node,
1593  *              if it hasn't been set already.
1594  *
1595  * Because of struct equivalence, this can also be used for
1596  * DistinctExpr and NullIfExpr nodes.
1597  */
1598 void
1599 set_opfuncid(OpExpr *opexpr)
1600 {
1601         if (opexpr->opfuncid == InvalidOid)
1602                 opexpr->opfuncid = get_opcode(opexpr->opno);
1603 }
1604
1605 /*
1606  * set_sa_opfuncid
1607  *              As above, for ScalarArrayOpExpr nodes.
1608  */
1609 void
1610 set_sa_opfuncid(ScalarArrayOpExpr *opexpr)
1611 {
1612         if (opexpr->opfuncid == InvalidOid)
1613                 opexpr->opfuncid = get_opcode(opexpr->opno);
1614 }
1615
1616 /*****************************************************************************
1617  *                                      QUERY DEPENDENCY MANAGEMENT
1618  *****************************************************************************/
1619
1620 /*
1621  * record_plan_function_dependency
1622  *              Mark the current plan as depending on a particular function.
1623  *
1624  * This is exported so that the function-inlining code can record a
1625  * dependency on a function that it's removed from the plan tree.
1626  */
1627 void
1628 record_plan_function_dependency(PlannerGlobal *glob, Oid funcid)
1629 {
1630         /*
1631          * For performance reasons, we don't bother to track built-in functions;
1632          * we just assume they'll never change (or at least not in ways that'd
1633          * invalidate plans using them).  For this purpose we can consider a
1634          * built-in function to be one with OID less than FirstBootstrapObjectId.
1635          * Note that the OID generator guarantees never to generate such an
1636          * OID after startup, even at OID wraparound.
1637          */
1638         if (funcid >= (Oid) FirstBootstrapObjectId)
1639         {
1640                 HeapTuple       func_tuple;
1641                 PlanInvalItem *inval_item;
1642
1643                 func_tuple = SearchSysCache(PROCOID,
1644                                                                         ObjectIdGetDatum(funcid),
1645                                                                         0, 0, 0);
1646                 if (!HeapTupleIsValid(func_tuple))
1647                         elog(ERROR, "cache lookup failed for function %u", funcid);
1648
1649                 inval_item = makeNode(PlanInvalItem);
1650
1651                 /*
1652                  * It would work to use any syscache on pg_proc, but plancache.c
1653                  * expects us to use PROCOID.
1654                  */
1655                 inval_item->cacheId = PROCOID;
1656                 inval_item->tupleId = func_tuple->t_self;
1657
1658                 glob->invalItems = lappend(glob->invalItems, inval_item);
1659
1660                 ReleaseSysCache(func_tuple);
1661         }
1662 }
1663
1664 /*
1665  * extract_query_dependencies
1666  *              Given a list of not-yet-planned queries (i.e. Query nodes),
1667  *              extract their dependencies just as set_plan_references would do.
1668  *
1669  * This is needed by plancache.c to handle invalidation of cached unplanned
1670  * queries.
1671  */
1672 void
1673 extract_query_dependencies(List *queries,
1674                                                    List **relationOids,
1675                                                    List **invalItems)
1676 {
1677         PlannerGlobal glob;
1678
1679         /* Make up a dummy PlannerGlobal so we can use this module's machinery */
1680         MemSet(&glob, 0, sizeof(glob));
1681         glob.type = T_PlannerGlobal;
1682         glob.relationOids = NIL;
1683         glob.invalItems = NIL;
1684
1685         (void) extract_query_dependencies_walker((Node *) queries, &glob);
1686
1687         *relationOids = glob.relationOids;
1688         *invalItems = glob.invalItems;
1689 }
1690
1691 static bool
1692 extract_query_dependencies_walker(Node *node, PlannerGlobal *context)
1693 {
1694         if (node == NULL)
1695                 return false;
1696         /* Extract function dependencies and check for regclass Consts */
1697         fix_expr_common(context, node);
1698         if (IsA(node, Query))
1699         {
1700                 Query      *query = (Query *) node;
1701                 ListCell   *lc;
1702
1703                 /* Collect relation OIDs in this Query's rtable */
1704                 foreach(lc, query->rtable)
1705                 {
1706                         RangeTblEntry *rte = (RangeTblEntry *) lfirst(lc);
1707
1708                         if (rte->rtekind == RTE_RELATION)
1709                                 context->relationOids = lappend_oid(context->relationOids,
1710                                                                                                         rte->relid);
1711                 }
1712
1713                 /* And recurse into the query's subexpressions */
1714                 return query_tree_walker(query, extract_query_dependencies_walker,
1715                                                                  (void *) context, 0);
1716         }
1717         return expression_tree_walker(node, extract_query_dependencies_walker,
1718                                                                   (void *) context);
1719 }