diff options
Diffstat (limited to 'src/backend/optimizer/plan/subselect.c')
| -rw-r--r-- | src/backend/optimizer/plan/subselect.c | 42 |
1 files changed, 30 insertions, 12 deletions
diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c index 42da081e059..3c72199777e 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 - * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.65 2003/01/13 00:29:26 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.66 2003/01/13 18:10:53 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -65,7 +65,7 @@ static List *convert_sublink_opers(List *lefthand, List *operOids, List *targetlist, List **paramIds); static bool subplan_is_hashable(SubLink *slink, SubPlan *node); static Node *replace_correlation_vars_mutator(Node *node, void *context); -static Node *process_sublinks_mutator(Node *node, void *context); +static Node *process_sublinks_mutator(Node *node, bool *isTopQual); static bool finalize_primnode(Node *node, finalize_primnode_results *results); @@ -159,7 +159,8 @@ generate_new_param(Oid paramtype, int32 paramtypmod) * Convert a bare SubLink (as created by the parser) into a SubPlan. * * We are given the raw SubLink and the already-processed lefthand argument - * list (use this instead of the SubLink's own field). + * list (use this instead of the SubLink's own field). We are also told if + * this expression appears at top level of a WHERE/HAVING qual. * * The result is whatever we need to substitute in place of the SubLink * node in the executable expression. This will be either the SubPlan @@ -168,7 +169,7 @@ generate_new_param(Oid paramtype, int32 paramtypmod) * containing InitPlan Param nodes. */ static Node * -make_subplan(SubLink *slink, List *lefthand) +make_subplan(SubLink *slink, List *lefthand, bool isTopQual) { SubPlan *node = makeNode(SubPlan); Query *subquery = (Query *) (slink->subselect); @@ -232,7 +233,8 @@ make_subplan(SubLink *slink, List *lefthand) node->exprs = NIL; node->paramIds = NIL; node->useHashTable = false; - node->unknownEqFalse = false; + /* At top level of a qual, can treat UNKNOWN the same as FALSE */ + node->unknownEqFalse = isTopQual; node->setParam = NIL; node->parParam = NIL; node->args = NIL; @@ -589,17 +591,23 @@ replace_correlation_vars_mutator(Node *node, void *context) /* * Expand SubLinks to SubPlans in the given expression. + * + * The isQual argument tells whether or not this expression is a WHERE/HAVING + * qualifier expression. If it is, any sublinks appearing at top level need + * not distinguish FALSE from UNKNOWN return values. */ Node * -SS_process_sublinks(Node *expr) +SS_process_sublinks(Node *expr, bool isQual) { - /* No setup needed for tree walk, so away we go */ - return process_sublinks_mutator(expr, NULL); + /* The only context needed is the initial are-we-in-a-qual flag */ + return process_sublinks_mutator(expr, &isQual); } static Node * -process_sublinks_mutator(Node *node, void *context) +process_sublinks_mutator(Node *node, bool *isTopQual) { + bool locTopQual; + if (node == NULL) return NULL; if (IsA(node, SubLink)) @@ -610,12 +618,13 @@ process_sublinks_mutator(Node *node, void *context) /* * First, recursively process the lefthand-side expressions, if any. */ + locTopQual = false; lefthand = (List *) - process_sublinks_mutator((Node *) sublink->lefthand, context); + process_sublinks_mutator((Node *) sublink->lefthand, &locTopQual); /* * Now build the SubPlan node and make the expr to return. */ - return make_subplan(sublink, lefthand); + return make_subplan(sublink, lefthand, *isTopQual); } /* @@ -626,9 +635,18 @@ process_sublinks_mutator(Node *node, void *context) */ Assert(!is_subplan(node)); + /* + * If we recurse down through anything other than a List node, we are + * definitely not at top qual level anymore. + */ + if (IsA(node, List)) + locTopQual = *isTopQual; + else + locTopQual = false; + return expression_tree_mutator(node, process_sublinks_mutator, - context); + (void *) &locTopQual); } /* |