diff options
Diffstat (limited to 'src/backend/optimizer/plan/subselect.c')
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 159 |
1 files changed, 116 insertions, 43 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index cf503d51135..b94419a09dc 100644 --- a/src/backend/optimizer/plan/subselect.c +++ b/src/backend/optimizer/plan/subselect.c @@ -7,7 +7,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.162 2010/04/19 00:55:25 rhaas Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.163 2010/07/12 17:01:06 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -83,30 +83,20 @@ static bool finalize_primnode(Node *node, finalize_primnode_context *context); /* - * Generate a Param node to replace the given Var, - * which is expected to have varlevelsup > 0 (ie, it is not local). + * Select a PARAM_EXEC number to identify the given Var. + * If the Var already has a param slot, return that one. */ -static Param * -replace_outer_var(PlannerInfo *root, Var *var) +static int +assign_param_for_var(PlannerInfo *root, Var *var) { - Param *retval; ListCell *ppl; PlannerParamItem *pitem; Index abslevel; int i; - Assert(var->varlevelsup > 0 && var->varlevelsup < root->query_level); abslevel = root->query_level - var->varlevelsup; - /* - * If there's already a paramlist entry for this same Var, just use it. - * NOTE: in sufficiently complex querytrees, it is possible for the same - * varno/abslevel to refer to different RTEs in different parts of the - * parsetree, so that different fields might end up sharing the same Param - * number. As long as we check the vartype/typmod as well, I believe that - * this sort of aliasing will cause no trouble. The correct field should - * get stored into the Param slot at execution in each part of the tree. - */ + /* If there's already a paramlist entry for this same Var, just use it */ i = 0; foreach(ppl, root->glob->paramlist) { @@ -119,24 +109,76 @@ replace_outer_var(PlannerInfo *root, Var *var) pvar->varattno == var->varattno && pvar->vartype == var->vartype && pvar->vartypmod == var->vartypmod) - break; + return i; } i++; } - if (!ppl) - { - /* Nope, so make a new one */ - var = (Var *) copyObject(var); - var->varlevelsup = 0; + /* Nope, so make a new one */ + var = (Var *) copyObject(var); + var->varlevelsup = 0; - pitem = makeNode(PlannerParamItem); - pitem->item = (Node *) var; - pitem->abslevel = abslevel; + pitem = makeNode(PlannerParamItem); + pitem->item = (Node *) var; + pitem->abslevel = abslevel; - root->glob->paramlist = lappend(root->glob->paramlist, pitem); - /* i is already the correct index for the new item */ - } + root->glob->paramlist = lappend(root->glob->paramlist, pitem); + + /* i is already the correct list index for the new item */ + return i; +} + +/* + * Generate a Param node to replace the given Var, + * which is expected to have varlevelsup > 0 (ie, it is not local). + */ +static Param * +replace_outer_var(PlannerInfo *root, Var *var) +{ + Param *retval; + int i; + + Assert(var->varlevelsup > 0 && var->varlevelsup < root->query_level); + + /* + * Find the Var in root->glob->paramlist, or add it if not present. + * + * NOTE: in sufficiently complex querytrees, it is possible for the same + * varno/abslevel to refer to different RTEs in different parts of the + * parsetree, so that different fields might end up sharing the same Param + * number. As long as we check the vartype/typmod as well, I believe that + * this sort of aliasing will cause no trouble. The correct field should + * get stored into the Param slot at execution in each part of the tree. + */ + i = assign_param_for_var(root, var); + + retval = makeNode(Param); + retval->paramkind = PARAM_EXEC; + retval->paramid = i; + retval->paramtype = var->vartype; + retval->paramtypmod = var->vartypmod; + retval->location = -1; + + return retval; +} + +/* + * Generate a Param node to replace the given Var, which will be supplied + * from an upper NestLoop join node. + * + * Because we allow nestloop and subquery Params to alias each other, + * this is effectively the same as replace_outer_var, except that we expect + * the Var to be local to the current query level. + */ +Param * +assign_nestloop_param(PlannerInfo *root, Var *var) +{ + Param *retval; + int i; + + Assert(var->varlevelsup == 0); + + i = assign_param_for_var(root, var); retval = makeNode(Param); retval->paramkind = PARAM_EXEC; @@ -1773,8 +1815,9 @@ SS_finalize_plan(PlannerInfo *root, Plan *plan, bool attach_initplans) * * Note: this is a bit overly generous since some parameters of upper * query levels might belong to query subtrees that don't include this - * query. However, valid_params is only a debugging crosscheck, so it - * doesn't seem worth expending lots of cycles to try to be exact. + * query, or might be nestloop params that won't be passed down at all. + * However, valid_params is only a debugging crosscheck, so it doesn't + * seem worth expending lots of cycles to try to be exact. */ valid_params = bms_copy(initSetParam); paramid = 0; @@ -1849,6 +1892,8 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params, { finalize_primnode_context context; int locally_added_param; + Bitmapset *nestloop_params; + Bitmapset *child_params; if (plan == NULL) return NULL; @@ -1856,6 +1901,7 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params, context.root = root; context.paramids = NULL; /* initialize set to empty */ locally_added_param = -1; /* there isn't one */ + nestloop_params = NULL; /* there aren't any */ /* * When we call finalize_primnode, context.paramids sets are automatically @@ -2056,8 +2102,20 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params, break; case T_NestLoop: - finalize_primnode((Node *) ((Join *) plan)->joinqual, - &context); + { + ListCell *l; + + finalize_primnode((Node *) ((Join *) plan)->joinqual, + &context); + /* collect set of params that will be passed to right child */ + foreach(l, ((NestLoop *) plan)->nestParams) + { + NestLoopParam *nlp = (NestLoopParam *) lfirst(l); + + nestloop_params = bms_add_member(nestloop_params, + nlp->paramno); + } + } break; case T_MergeJoin: @@ -2120,17 +2178,32 @@ finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params, } /* Process left and right child plans, if any */ - context.paramids = bms_add_members(context.paramids, - finalize_plan(root, - plan->lefttree, - valid_params, - scan_params)); - - context.paramids = bms_add_members(context.paramids, - finalize_plan(root, - plan->righttree, - valid_params, - scan_params)); + child_params = finalize_plan(root, + plan->lefttree, + valid_params, + scan_params); + context.paramids = bms_add_members(context.paramids, child_params); + + if (nestloop_params) + { + /* right child can reference nestloop_params as well as valid_params */ + child_params = finalize_plan(root, + plan->righttree, + bms_union(nestloop_params, valid_params), + scan_params); + /* ... and they don't count as parameters used at my level */ + child_params = bms_difference(child_params, nestloop_params); + bms_free(nestloop_params); + } + else + { + /* easy case */ + child_params = finalize_plan(root, + plan->righttree, + valid_params, + scan_params); + } + context.paramids = bms_add_members(context.paramids, child_params); /* * Any locally generated parameter doesn't count towards its generating |