LCOV - code coverage report
Current view: top level - src/backend/optimizer/util - paramassign.c (source / functions) Hit Total Coverage
Test: PostgreSQL 18devel Lines: 213 222 95.9 %
Date: 2024-11-21 08:14:44 Functions: 13 13 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * paramassign.c
       4             :  *      Functions for assigning PARAM_EXEC slots during planning.
       5             :  *
       6             :  * This module is responsible for managing three planner data structures:
       7             :  *
       8             :  * root->glob->paramExecTypes: records actual assignments of PARAM_EXEC slots.
       9             :  * The i'th list element holds the data type OID of the i'th parameter slot.
      10             :  * (Elements can be InvalidOid if they represent slots that are needed for
      11             :  * chgParam signaling, but will never hold a value at runtime.)  This list is
      12             :  * global to the whole plan since the executor has only one PARAM_EXEC array.
      13             :  * Assignments are permanent for the plan: we never remove entries once added.
      14             :  *
      15             :  * root->plan_params: a list of PlannerParamItem nodes, recording Vars and
      16             :  * PlaceHolderVars that the root's query level needs to supply to lower-level
      17             :  * subqueries, along with the PARAM_EXEC number to use for each such value.
      18             :  * Elements are added to this list while planning a subquery, and the list
      19             :  * is reset to empty after completion of each subquery.
      20             :  *
      21             :  * root->curOuterParams: a list of NestLoopParam nodes, recording Vars and
      22             :  * PlaceHolderVars that some outer level of nestloop needs to pass down to
      23             :  * a lower-level plan node in its righthand side.  Elements are added to this
      24             :  * list as createplan.c creates lower Plan nodes that need such Params, and
      25             :  * are removed when it creates a NestLoop Plan node that will supply those
      26             :  * values.
      27             :  *
      28             :  * The latter two data structures are used to prevent creating multiple
      29             :  * PARAM_EXEC slots (each requiring work to fill) when the same upper
      30             :  * SubPlan or NestLoop supplies a value that is referenced in more than
      31             :  * one place in its child plan nodes.  However, when the same Var has to
      32             :  * be supplied to different subplan trees by different SubPlan or NestLoop
      33             :  * parent nodes, we don't recognize any commonality; a fresh plan_params or
      34             :  * curOuterParams entry will be made (since the old one has been removed
      35             :  * when we finished processing the earlier SubPlan or NestLoop) and a fresh
      36             :  * PARAM_EXEC number will be assigned.  At one time we tried to avoid
      37             :  * allocating duplicate PARAM_EXEC numbers in such cases, but it's harder
      38             :  * than it seems to avoid bugs due to overlapping Param lifetimes, so we
      39             :  * don't risk that anymore.  Minimizing the number of PARAM_EXEC slots
      40             :  * doesn't really save much executor work anyway.
      41             :  *
      42             :  *
      43             :  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
      44             :  * Portions Copyright (c) 1994, Regents of the University of California
      45             :  *
      46             :  * IDENTIFICATION
      47             :  *    src/backend/optimizer/util/paramassign.c
      48             :  *
      49             :  *-------------------------------------------------------------------------
      50             :  */
      51             : #include "postgres.h"
      52             : 
      53             : #include "nodes/nodeFuncs.h"
      54             : #include "nodes/plannodes.h"
      55             : #include "optimizer/paramassign.h"
      56             : #include "optimizer/placeholder.h"
      57             : #include "rewrite/rewriteManip.h"
      58             : 
      59             : 
      60             : /*
      61             :  * Select a PARAM_EXEC number to identify the given Var as a parameter for
      62             :  * the current subquery.  (It might already have one.)
      63             :  * Record the need for the Var in the proper upper-level root->plan_params.
      64             :  */
      65             : static int
      66       48032 : assign_param_for_var(PlannerInfo *root, Var *var)
      67             : {
      68             :     ListCell   *ppl;
      69             :     PlannerParamItem *pitem;
      70             :     Index       levelsup;
      71             : 
      72             :     /* Find the query level the Var belongs to */
      73       96494 :     for (levelsup = var->varlevelsup; levelsup > 0; levelsup--)
      74       48462 :         root = root->parent_root;
      75             : 
      76             :     /* If there's already a matching PlannerParamItem there, just use it */
      77       70968 :     foreach(ppl, root->plan_params)
      78             :     {
      79       30302 :         pitem = (PlannerParamItem *) lfirst(ppl);
      80       30302 :         if (IsA(pitem->item, Var))
      81             :         {
      82       30302 :             Var        *pvar = (Var *) pitem->item;
      83             : 
      84             :             /*
      85             :              * This comparison must match _equalVar(), except for ignoring
      86             :              * varlevelsup.  Note that _equalVar() ignores varnosyn,
      87             :              * varattnosyn, and location, so this does too.
      88             :              */
      89       30302 :             if (pvar->varno == var->varno &&
      90       28226 :                 pvar->varattno == var->varattno &&
      91        7366 :                 pvar->vartype == var->vartype &&
      92        7366 :                 pvar->vartypmod == var->vartypmod &&
      93       14732 :                 pvar->varcollid == var->varcollid &&
      94        7366 :                 bms_equal(pvar->varnullingrels, var->varnullingrels))
      95        7366 :                 return pitem->paramId;
      96             :         }
      97             :     }
      98             : 
      99             :     /* Nope, so make a new one */
     100       40666 :     var = copyObject(var);
     101       40666 :     var->varlevelsup = 0;
     102             : 
     103       40666 :     pitem = makeNode(PlannerParamItem);
     104       40666 :     pitem->item = (Node *) var;
     105       40666 :     pitem->paramId = list_length(root->glob->paramExecTypes);
     106       40666 :     root->glob->paramExecTypes = lappend_oid(root->glob->paramExecTypes,
     107             :                                              var->vartype);
     108             : 
     109       40666 :     root->plan_params = lappend(root->plan_params, pitem);
     110             : 
     111       40666 :     return pitem->paramId;
     112             : }
     113             : 
     114             : /*
     115             :  * Generate a Param node to replace the given Var,
     116             :  * which is expected to have varlevelsup > 0 (ie, it is not local).
     117             :  * Record the need for the Var in the proper upper-level root->plan_params.
     118             :  */
     119             : Param *
     120       48032 : replace_outer_var(PlannerInfo *root, Var *var)
     121             : {
     122             :     Param      *retval;
     123             :     int         i;
     124             : 
     125             :     Assert(var->varlevelsup > 0 && var->varlevelsup < root->query_level);
     126             : 
     127             :     /* Find the Var in the appropriate plan_params, or add it if not present */
     128       48032 :     i = assign_param_for_var(root, var);
     129             : 
     130       48032 :     retval = makeNode(Param);
     131       48032 :     retval->paramkind = PARAM_EXEC;
     132       48032 :     retval->paramid = i;
     133       48032 :     retval->paramtype = var->vartype;
     134       48032 :     retval->paramtypmod = var->vartypmod;
     135       48032 :     retval->paramcollid = var->varcollid;
     136       48032 :     retval->location = var->location;
     137             : 
     138       48032 :     return retval;
     139             : }
     140             : 
     141             : /*
     142             :  * Select a PARAM_EXEC number to identify the given PlaceHolderVar as a
     143             :  * parameter for the current subquery.  (It might already have one.)
     144             :  * Record the need for the PHV in the proper upper-level root->plan_params.
     145             :  *
     146             :  * This is just like assign_param_for_var, except for PlaceHolderVars.
     147             :  */
     148             : static int
     149          42 : assign_param_for_placeholdervar(PlannerInfo *root, PlaceHolderVar *phv)
     150             : {
     151             :     ListCell   *ppl;
     152             :     PlannerParamItem *pitem;
     153             :     Index       levelsup;
     154             : 
     155             :     /* Find the query level the PHV belongs to */
     156          84 :     for (levelsup = phv->phlevelsup; levelsup > 0; levelsup--)
     157          42 :         root = root->parent_root;
     158             : 
     159             :     /* If there's already a matching PlannerParamItem there, just use it */
     160         102 :     foreach(ppl, root->plan_params)
     161             :     {
     162          60 :         pitem = (PlannerParamItem *) lfirst(ppl);
     163          60 :         if (IsA(pitem->item, PlaceHolderVar))
     164             :         {
     165           0 :             PlaceHolderVar *pphv = (PlaceHolderVar *) pitem->item;
     166             : 
     167             :             /* We assume comparing the PHIDs is sufficient */
     168           0 :             if (pphv->phid == phv->phid)
     169           0 :                 return pitem->paramId;
     170             :         }
     171             :     }
     172             : 
     173             :     /* Nope, so make a new one */
     174          42 :     phv = copyObject(phv);
     175          42 :     IncrementVarSublevelsUp((Node *) phv, -((int) phv->phlevelsup), 0);
     176             :     Assert(phv->phlevelsup == 0);
     177             : 
     178          42 :     pitem = makeNode(PlannerParamItem);
     179          42 :     pitem->item = (Node *) phv;
     180          42 :     pitem->paramId = list_length(root->glob->paramExecTypes);
     181          42 :     root->glob->paramExecTypes = lappend_oid(root->glob->paramExecTypes,
     182          42 :                                              exprType((Node *) phv->phexpr));
     183             : 
     184          42 :     root->plan_params = lappend(root->plan_params, pitem);
     185             : 
     186          42 :     return pitem->paramId;
     187             : }
     188             : 
     189             : /*
     190             :  * Generate a Param node to replace the given PlaceHolderVar,
     191             :  * which is expected to have phlevelsup > 0 (ie, it is not local).
     192             :  * Record the need for the PHV in the proper upper-level root->plan_params.
     193             :  *
     194             :  * This is just like replace_outer_var, except for PlaceHolderVars.
     195             :  */
     196             : Param *
     197          42 : replace_outer_placeholdervar(PlannerInfo *root, PlaceHolderVar *phv)
     198             : {
     199             :     Param      *retval;
     200             :     int         i;
     201             : 
     202             :     Assert(phv->phlevelsup > 0 && phv->phlevelsup < root->query_level);
     203             : 
     204             :     /* Find the PHV in the appropriate plan_params, or add it if not present */
     205          42 :     i = assign_param_for_placeholdervar(root, phv);
     206             : 
     207          42 :     retval = makeNode(Param);
     208          42 :     retval->paramkind = PARAM_EXEC;
     209          42 :     retval->paramid = i;
     210          42 :     retval->paramtype = exprType((Node *) phv->phexpr);
     211          42 :     retval->paramtypmod = exprTypmod((Node *) phv->phexpr);
     212          42 :     retval->paramcollid = exprCollation((Node *) phv->phexpr);
     213          42 :     retval->location = -1;
     214             : 
     215          42 :     return retval;
     216             : }
     217             : 
     218             : /*
     219             :  * Generate a Param node to replace the given Aggref
     220             :  * which is expected to have agglevelsup > 0 (ie, it is not local).
     221             :  * Record the need for the Aggref in the proper upper-level root->plan_params.
     222             :  */
     223             : Param *
     224          52 : replace_outer_agg(PlannerInfo *root, Aggref *agg)
     225             : {
     226             :     Param      *retval;
     227             :     PlannerParamItem *pitem;
     228             :     Index       levelsup;
     229             : 
     230             :     Assert(agg->agglevelsup > 0 && agg->agglevelsup < root->query_level);
     231             : 
     232             :     /* Find the query level the Aggref belongs to */
     233         104 :     for (levelsup = agg->agglevelsup; levelsup > 0; levelsup--)
     234          52 :         root = root->parent_root;
     235             : 
     236             :     /*
     237             :      * It does not seem worthwhile to try to de-duplicate references to outer
     238             :      * aggs.  Just make a new slot every time.
     239             :      */
     240          52 :     agg = copyObject(agg);
     241          52 :     IncrementVarSublevelsUp((Node *) agg, -((int) agg->agglevelsup), 0);
     242             :     Assert(agg->agglevelsup == 0);
     243             : 
     244          52 :     pitem = makeNode(PlannerParamItem);
     245          52 :     pitem->item = (Node *) agg;
     246          52 :     pitem->paramId = list_length(root->glob->paramExecTypes);
     247          52 :     root->glob->paramExecTypes = lappend_oid(root->glob->paramExecTypes,
     248             :                                              agg->aggtype);
     249             : 
     250          52 :     root->plan_params = lappend(root->plan_params, pitem);
     251             : 
     252          52 :     retval = makeNode(Param);
     253          52 :     retval->paramkind = PARAM_EXEC;
     254          52 :     retval->paramid = pitem->paramId;
     255          52 :     retval->paramtype = agg->aggtype;
     256          52 :     retval->paramtypmod = -1;
     257          52 :     retval->paramcollid = agg->aggcollid;
     258          52 :     retval->location = agg->location;
     259             : 
     260          52 :     return retval;
     261             : }
     262             : 
     263             : /*
     264             :  * Generate a Param node to replace the given GroupingFunc expression which is
     265             :  * expected to have agglevelsup > 0 (ie, it is not local).
     266             :  * Record the need for the GroupingFunc in the proper upper-level
     267             :  * root->plan_params.
     268             :  */
     269             : Param *
     270          64 : replace_outer_grouping(PlannerInfo *root, GroupingFunc *grp)
     271             : {
     272             :     Param      *retval;
     273             :     PlannerParamItem *pitem;
     274             :     Index       levelsup;
     275          64 :     Oid         ptype = exprType((Node *) grp);
     276             : 
     277             :     Assert(grp->agglevelsup > 0 && grp->agglevelsup < root->query_level);
     278             : 
     279             :     /* Find the query level the GroupingFunc belongs to */
     280         136 :     for (levelsup = grp->agglevelsup; levelsup > 0; levelsup--)
     281          72 :         root = root->parent_root;
     282             : 
     283             :     /*
     284             :      * It does not seem worthwhile to try to de-duplicate references to outer
     285             :      * aggs.  Just make a new slot every time.
     286             :      */
     287          64 :     grp = copyObject(grp);
     288          64 :     IncrementVarSublevelsUp((Node *) grp, -((int) grp->agglevelsup), 0);
     289             :     Assert(grp->agglevelsup == 0);
     290             : 
     291          64 :     pitem = makeNode(PlannerParamItem);
     292          64 :     pitem->item = (Node *) grp;
     293          64 :     pitem->paramId = list_length(root->glob->paramExecTypes);
     294          64 :     root->glob->paramExecTypes = lappend_oid(root->glob->paramExecTypes,
     295             :                                              ptype);
     296             : 
     297          64 :     root->plan_params = lappend(root->plan_params, pitem);
     298             : 
     299          64 :     retval = makeNode(Param);
     300          64 :     retval->paramkind = PARAM_EXEC;
     301          64 :     retval->paramid = pitem->paramId;
     302          64 :     retval->paramtype = ptype;
     303          64 :     retval->paramtypmod = -1;
     304          64 :     retval->paramcollid = InvalidOid;
     305          64 :     retval->location = grp->location;
     306             : 
     307          64 :     return retval;
     308             : }
     309             : 
     310             : /*
     311             :  * Generate a Param node to replace the given MergeSupportFunc expression
     312             :  * which is expected to be in the RETURNING list of an upper-level MERGE
     313             :  * query.  Record the need for the MergeSupportFunc in the proper upper-level
     314             :  * root->plan_params.
     315             :  */
     316             : Param *
     317           6 : replace_outer_merge_support(PlannerInfo *root, MergeSupportFunc *msf)
     318             : {
     319             :     Param      *retval;
     320             :     PlannerParamItem *pitem;
     321           6 :     Oid         ptype = exprType((Node *) msf);
     322             : 
     323             :     Assert(root->parse->commandType != CMD_MERGE);
     324             : 
     325             :     /*
     326             :      * The parser should have ensured that the MergeSupportFunc is in the
     327             :      * RETURNING list of an upper-level MERGE query, so find that query.
     328             :      */
     329             :     do
     330             :     {
     331           6 :         root = root->parent_root;
     332           6 :         if (root == NULL)
     333           0 :             elog(ERROR, "MergeSupportFunc found outside MERGE");
     334           6 :     } while (root->parse->commandType != CMD_MERGE);
     335             : 
     336             :     /*
     337             :      * It does not seem worthwhile to try to de-duplicate references to outer
     338             :      * MergeSupportFunc expressions.  Just make a new slot every time.
     339             :      */
     340           6 :     msf = copyObject(msf);
     341             : 
     342           6 :     pitem = makeNode(PlannerParamItem);
     343           6 :     pitem->item = (Node *) msf;
     344           6 :     pitem->paramId = list_length(root->glob->paramExecTypes);
     345           6 :     root->glob->paramExecTypes = lappend_oid(root->glob->paramExecTypes,
     346             :                                              ptype);
     347             : 
     348           6 :     root->plan_params = lappend(root->plan_params, pitem);
     349             : 
     350           6 :     retval = makeNode(Param);
     351           6 :     retval->paramkind = PARAM_EXEC;
     352           6 :     retval->paramid = pitem->paramId;
     353           6 :     retval->paramtype = ptype;
     354           6 :     retval->paramtypmod = -1;
     355           6 :     retval->paramcollid = InvalidOid;
     356           6 :     retval->location = msf->location;
     357             : 
     358           6 :     return retval;
     359             : }
     360             : 
     361             : /*
     362             :  * Generate a Param node to replace the given Var,
     363             :  * which is expected to come from some upper NestLoop plan node.
     364             :  * Record the need for the Var in root->curOuterParams.
     365             :  */
     366             : Param *
     367       83394 : replace_nestloop_param_var(PlannerInfo *root, Var *var)
     368             : {
     369             :     Param      *param;
     370             :     NestLoopParam *nlp;
     371             :     ListCell   *lc;
     372             : 
     373             :     /* Is this Var already listed in root->curOuterParams? */
     374       92078 :     foreach(lc, root->curOuterParams)
     375             :     {
     376       46530 :         nlp = (NestLoopParam *) lfirst(lc);
     377       46530 :         if (equal(var, nlp->paramval))
     378             :         {
     379             :             /* Yes, so just make a Param referencing this NLP's slot */
     380       37846 :             param = makeNode(Param);
     381       37846 :             param->paramkind = PARAM_EXEC;
     382       37846 :             param->paramid = nlp->paramno;
     383       37846 :             param->paramtype = var->vartype;
     384       37846 :             param->paramtypmod = var->vartypmod;
     385       37846 :             param->paramcollid = var->varcollid;
     386       37846 :             param->location = var->location;
     387       37846 :             return param;
     388             :         }
     389             :     }
     390             : 
     391             :     /* No, so assign a PARAM_EXEC slot for a new NLP */
     392       45548 :     param = generate_new_exec_param(root,
     393             :                                     var->vartype,
     394             :                                     var->vartypmod,
     395             :                                     var->varcollid);
     396       45548 :     param->location = var->location;
     397             : 
     398             :     /* Add it to the list of required NLPs */
     399       45548 :     nlp = makeNode(NestLoopParam);
     400       45548 :     nlp->paramno = param->paramid;
     401       45548 :     nlp->paramval = copyObject(var);
     402       45548 :     root->curOuterParams = lappend(root->curOuterParams, nlp);
     403             : 
     404             :     /* And return the replacement Param */
     405       45548 :     return param;
     406             : }
     407             : 
     408             : /*
     409             :  * Generate a Param node to replace the given PlaceHolderVar,
     410             :  * which is expected to come from some upper NestLoop plan node.
     411             :  * Record the need for the PHV in root->curOuterParams.
     412             :  *
     413             :  * This is just like replace_nestloop_param_var, except for PlaceHolderVars.
     414             :  */
     415             : Param *
     416         246 : replace_nestloop_param_placeholdervar(PlannerInfo *root, PlaceHolderVar *phv)
     417             : {
     418             :     Param      *param;
     419             :     NestLoopParam *nlp;
     420             :     ListCell   *lc;
     421             : 
     422             :     /* Is this PHV already listed in root->curOuterParams? */
     423         324 :     foreach(lc, root->curOuterParams)
     424             :     {
     425         180 :         nlp = (NestLoopParam *) lfirst(lc);
     426         180 :         if (equal(phv, nlp->paramval))
     427             :         {
     428             :             /* Yes, so just make a Param referencing this NLP's slot */
     429         102 :             param = makeNode(Param);
     430         102 :             param->paramkind = PARAM_EXEC;
     431         102 :             param->paramid = nlp->paramno;
     432         102 :             param->paramtype = exprType((Node *) phv->phexpr);
     433         102 :             param->paramtypmod = exprTypmod((Node *) phv->phexpr);
     434         102 :             param->paramcollid = exprCollation((Node *) phv->phexpr);
     435         102 :             param->location = -1;
     436         102 :             return param;
     437             :         }
     438             :     }
     439             : 
     440             :     /* No, so assign a PARAM_EXEC slot for a new NLP */
     441         144 :     param = generate_new_exec_param(root,
     442         144 :                                     exprType((Node *) phv->phexpr),
     443         144 :                                     exprTypmod((Node *) phv->phexpr),
     444         144 :                                     exprCollation((Node *) phv->phexpr));
     445             : 
     446             :     /* Add it to the list of required NLPs */
     447         144 :     nlp = makeNode(NestLoopParam);
     448         144 :     nlp->paramno = param->paramid;
     449         144 :     nlp->paramval = (Var *) copyObject(phv);
     450         144 :     root->curOuterParams = lappend(root->curOuterParams, nlp);
     451             : 
     452             :     /* And return the replacement Param */
     453         144 :     return param;
     454             : }
     455             : 
     456             : /*
     457             :  * process_subquery_nestloop_params
     458             :  *    Handle params of a parameterized subquery that need to be fed
     459             :  *    from an outer nestloop.
     460             :  *
     461             :  * Currently, that would be *all* params that a subquery in FROM has demanded
     462             :  * from the current query level, since they must be LATERAL references.
     463             :  *
     464             :  * subplan_params is a list of PlannerParamItems that we intend to pass to
     465             :  * a subquery-in-FROM.  (This was constructed in root->plan_params while
     466             :  * planning the subquery, but isn't there anymore when this is called.)
     467             :  *
     468             :  * The subplan's references to the outer variables are already represented
     469             :  * as PARAM_EXEC Params, since that conversion was done by the routines above
     470             :  * while planning the subquery.  So we need not modify the subplan or the
     471             :  * PlannerParamItems here.  What we do need to do is add entries to
     472             :  * root->curOuterParams to signal the parent nestloop plan node that it must
     473             :  * provide these values.  This differs from replace_nestloop_param_var in
     474             :  * that the PARAM_EXEC slots to use have already been determined.
     475             :  *
     476             :  * Note that we also use root->curOuterRels as an implicit parameter for
     477             :  * sanity checks.
     478             :  */
     479             : void
     480         454 : process_subquery_nestloop_params(PlannerInfo *root, List *subplan_params)
     481             : {
     482             :     ListCell   *lc;
     483             : 
     484        1016 :     foreach(lc, subplan_params)
     485             :     {
     486         562 :         PlannerParamItem *pitem = lfirst_node(PlannerParamItem, lc);
     487             : 
     488         562 :         if (IsA(pitem->item, Var))
     489             :         {
     490         532 :             Var        *var = (Var *) pitem->item;
     491             :             NestLoopParam *nlp;
     492             :             ListCell   *lc2;
     493             : 
     494             :             /* If not from a nestloop outer rel, complain */
     495         532 :             if (!bms_is_member(var->varno, root->curOuterRels))
     496           0 :                 elog(ERROR, "non-LATERAL parameter required by subquery");
     497             : 
     498             :             /* Is this param already listed in root->curOuterParams? */
     499         724 :             foreach(lc2, root->curOuterParams)
     500             :             {
     501         192 :                 nlp = (NestLoopParam *) lfirst(lc2);
     502         192 :                 if (nlp->paramno == pitem->paramId)
     503             :                 {
     504             :                     Assert(equal(var, nlp->paramval));
     505             :                     /* Present, so nothing to do */
     506           0 :                     break;
     507             :                 }
     508             :             }
     509         532 :             if (lc2 == NULL)
     510             :             {
     511             :                 /* No, so add it */
     512         532 :                 nlp = makeNode(NestLoopParam);
     513         532 :                 nlp->paramno = pitem->paramId;
     514         532 :                 nlp->paramval = copyObject(var);
     515         532 :                 root->curOuterParams = lappend(root->curOuterParams, nlp);
     516             :             }
     517             :         }
     518          30 :         else if (IsA(pitem->item, PlaceHolderVar))
     519             :         {
     520          30 :             PlaceHolderVar *phv = (PlaceHolderVar *) pitem->item;
     521             :             NestLoopParam *nlp;
     522             :             ListCell   *lc2;
     523             : 
     524             :             /* If not from a nestloop outer rel, complain */
     525          30 :             if (!bms_is_subset(find_placeholder_info(root, phv)->ph_eval_at,
     526          30 :                                root->curOuterRels))
     527           0 :                 elog(ERROR, "non-LATERAL parameter required by subquery");
     528             : 
     529             :             /* Is this param already listed in root->curOuterParams? */
     530          90 :             foreach(lc2, root->curOuterParams)
     531             :             {
     532          60 :                 nlp = (NestLoopParam *) lfirst(lc2);
     533          60 :                 if (nlp->paramno == pitem->paramId)
     534             :                 {
     535             :                     Assert(equal(phv, nlp->paramval));
     536             :                     /* Present, so nothing to do */
     537           0 :                     break;
     538             :                 }
     539             :             }
     540          30 :             if (lc2 == NULL)
     541             :             {
     542             :                 /* No, so add it */
     543          30 :                 nlp = makeNode(NestLoopParam);
     544          30 :                 nlp->paramno = pitem->paramId;
     545          30 :                 nlp->paramval = (Var *) copyObject(phv);
     546          30 :                 root->curOuterParams = lappend(root->curOuterParams, nlp);
     547             :             }
     548             :         }
     549             :         else
     550           0 :             elog(ERROR, "unexpected type of subquery parameter");
     551             :     }
     552         454 : }
     553             : 
     554             : /*
     555             :  * Identify any NestLoopParams that should be supplied by a NestLoop plan
     556             :  * node with the specified lefthand rels.  Remove them from the active
     557             :  * root->curOuterParams list and return them as the result list.
     558             :  *
     559             :  * XXX Here we also hack up the returned Vars and PHVs so that they do not
     560             :  * contain nullingrel sets exceeding what is available from the outer side.
     561             :  * This is needed if we have applied outer join identity 3,
     562             :  *      (A leftjoin B on (Pab)) leftjoin C on (Pb*c)
     563             :  *      = A leftjoin (B leftjoin C on (Pbc)) on (Pab)
     564             :  * and C contains lateral references to B.  It's still safe to apply the
     565             :  * identity, but the parser will have created those references in the form
     566             :  * "b*" (i.e., with varnullingrels listing the A/B join), while what we will
     567             :  * have available from the nestloop's outer side is just "b".  We deal with
     568             :  * that here by stripping the nullingrels down to what is available from the
     569             :  * outer side according to leftrelids.
     570             :  *
     571             :  * That fixes matters for the case of forward application of identity 3.
     572             :  * If the identity was applied in the reverse direction, we will have
     573             :  * parameter Vars containing too few nullingrel bits rather than too many.
     574             :  * Currently, that causes no problems because setrefs.c applies only a
     575             :  * subset check to nullingrels in NestLoopParams, but we'd have to work
     576             :  * harder if we ever want to tighten that check.  This is all pretty annoying
     577             :  * because it greatly weakens setrefs.c's cross-check, but the alternative
     578             :  * seems to be to generate multiple versions of each laterally-parameterized
     579             :  * subquery, which'd be unduly expensive.
     580             :  */
     581             : List *
     582       81712 : identify_current_nestloop_params(PlannerInfo *root, Relids leftrelids)
     583             : {
     584             :     List       *result;
     585             :     ListCell   *cell;
     586             : 
     587       81712 :     result = NIL;
     588      128918 :     foreach(cell, root->curOuterParams)
     589             :     {
     590       47206 :         NestLoopParam *nlp = (NestLoopParam *) lfirst(cell);
     591             : 
     592             :         /*
     593             :          * We are looking for Vars and PHVs that can be supplied by the
     594             :          * lefthand rels.  When we find one, it's okay to modify it in-place
     595             :          * because all the routines above make a fresh copy to put into
     596             :          * curOuterParams.
     597             :          */
     598       94238 :         if (IsA(nlp->paramval, Var) &&
     599       47032 :             bms_is_member(nlp->paramval->varno, leftrelids))
     600       46080 :         {
     601       46080 :             Var        *var = (Var *) nlp->paramval;
     602             : 
     603       46080 :             root->curOuterParams = foreach_delete_current(root->curOuterParams,
     604             :                                                           cell);
     605       46080 :             var->varnullingrels = bms_intersect(var->varnullingrels,
     606             :                                                 leftrelids);
     607       46080 :             result = lappend(result, nlp);
     608             :         }
     609        1300 :         else if (IsA(nlp->paramval, PlaceHolderVar) &&
     610         348 :                  bms_is_subset(find_placeholder_info(root,
     611         174 :                                                      (PlaceHolderVar *) nlp->paramval)->ph_eval_at,
     612             :                                leftrelids))
     613             :         {
     614         174 :             PlaceHolderVar *phv = (PlaceHolderVar *) nlp->paramval;
     615             : 
     616         174 :             root->curOuterParams = foreach_delete_current(root->curOuterParams,
     617             :                                                           cell);
     618         174 :             phv->phnullingrels = bms_intersect(phv->phnullingrels,
     619             :                                                leftrelids);
     620         174 :             result = lappend(result, nlp);
     621             :         }
     622             :     }
     623       81712 :     return result;
     624             : }
     625             : 
     626             : /*
     627             :  * Generate a new Param node that will not conflict with any other.
     628             :  *
     629             :  * This is used to create Params representing subplan outputs or
     630             :  * NestLoop parameters.
     631             :  *
     632             :  * We don't need to build a PlannerParamItem for such a Param, but we do
     633             :  * need to make sure we record the type in paramExecTypes (otherwise,
     634             :  * there won't be a slot allocated for it).
     635             :  */
     636             : Param *
     637       58252 : generate_new_exec_param(PlannerInfo *root, Oid paramtype, int32 paramtypmod,
     638             :                         Oid paramcollation)
     639             : {
     640             :     Param      *retval;
     641             : 
     642       58252 :     retval = makeNode(Param);
     643       58252 :     retval->paramkind = PARAM_EXEC;
     644       58252 :     retval->paramid = list_length(root->glob->paramExecTypes);
     645       58252 :     root->glob->paramExecTypes = lappend_oid(root->glob->paramExecTypes,
     646             :                                              paramtype);
     647       58252 :     retval->paramtype = paramtype;
     648       58252 :     retval->paramtypmod = paramtypmod;
     649       58252 :     retval->paramcollid = paramcollation;
     650       58252 :     retval->location = -1;
     651             : 
     652       58252 :     return retval;
     653             : }
     654             : 
     655             : /*
     656             :  * Assign a (nonnegative) PARAM_EXEC ID for a special parameter (one that
     657             :  * is not actually used to carry a value at runtime).  Such parameters are
     658             :  * used for special runtime signaling purposes, such as connecting a
     659             :  * recursive union node to its worktable scan node or forcing plan
     660             :  * re-evaluation within the EvalPlanQual mechanism.  No actual Param node
     661             :  * exists with this ID, however.
     662             :  */
     663             : int
     664      102630 : assign_special_exec_param(PlannerInfo *root)
     665             : {
     666      102630 :     int         paramId = list_length(root->glob->paramExecTypes);
     667             : 
     668      102630 :     root->glob->paramExecTypes = lappend_oid(root->glob->paramExecTypes,
     669             :                                              InvalidOid);
     670      102630 :     return paramId;
     671             : }

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