diff options
Diffstat (limited to 'src/backend/optimizer/plan/planner.c')
| -rw-r--r-- | src/backend/optimizer/plan/planner.c | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c index ecdd7280eb8..d58635c887c 100644 --- a/src/backend/optimizer/plan/planner.c +++ b/src/backend/optimizer/plan/planner.c @@ -777,6 +777,27 @@ subquery_planner(PlannerGlobal *glob, Query *parse, } /* + * Now that we are done preprocessing expressions, and in particular done + * flattening join alias variables, get rid of the joinaliasvars lists. + * They no longer match what expressions in the rest of the tree look + * like, because we have not preprocessed expressions in those lists (and + * do not want to; for example, expanding a SubLink there would result in + * a useless unreferenced subplan). Leaving them in place simply creates + * a hazard for later scans of the tree. We could try to prevent that by + * using QTW_IGNORE_JOINALIASES in every tree scan done after this point, + * but that doesn't sound very reliable. + */ + if (root->hasJoinRTEs) + { + foreach(l, parse->rtable) + { + RangeTblEntry *rte = lfirst_node(RangeTblEntry, l); + + rte->joinaliasvars = NIL; + } + } + + /* * In some cases we may want to transfer a HAVING clause into WHERE. We * cannot do so if the HAVING clause contains aggregates (obviously) or * volatile functions (since a HAVING clause is supposed to be executed @@ -902,11 +923,12 @@ preprocess_expression(PlannerInfo *root, Node *expr, int kind) /* * If the query has any join RTEs, replace join alias variables with - * base-relation variables. We must do this before sublink processing, - * else sublinks expanded out from join aliases would not get processed. - * We can skip it in non-lateral RTE functions, VALUES lists, and - * TABLESAMPLE clauses, however, since they can't contain any Vars of the - * current query level. + * base-relation variables. We must do this first, since any expressions + * we may extract from the joinaliasvars lists have not been preprocessed. + * For example, if we did this after sublink processing, sublinks expanded + * out from join aliases would not get processed. But we can skip this in + * non-lateral RTE functions, VALUES lists, and TABLESAMPLE clauses, since + * they can't contain any Vars of the current query level. */ if (root->hasJoinRTEs && !(kind == EXPRKIND_RTFUNC || |