diff options
Diffstat (limited to 'src/backend/optimizer/prep/prepunion.c')
| -rw-r--r-- | src/backend/optimizer/prep/prepunion.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c index 0c68ec011be..8eaa734916d 100644 --- a/src/backend/optimizer/prep/prepunion.c +++ b/src/backend/optimizer/prep/prepunion.c @@ -324,7 +324,7 @@ recurse_set_operations(Node *setOp, PlannerInfo *root, * anyway; otherwise do statistical estimation. * * XXX you don't really want to know about this: we do the estimation - * using the subquery's original targetlist expressions, not the + * using the subroot->parse's original targetlist expressions, not the * subroot->processed_tlist which might seem more appropriate. The * reason is that if the subquery is itself a setop, it may return a * processed_tlist containing "varno 0" Vars generated by @@ -332,6 +332,9 @@ recurse_set_operations(Node *setOp, PlannerInfo *root, * mightily. We ought to get rid of the "varno 0" hack, but that * requires a redesign of the parsetree representation of setops, so * that there can be an RTE corresponding to each setop's output. + * Note, we use this not subquery's targetlist but subroot->parse's + * targetlist, because it was revised by self-join removal. subquery's + * targetlist might contain the references to the removed relids. */ if (pNumGroups) { @@ -341,7 +344,7 @@ recurse_set_operations(Node *setOp, PlannerInfo *root, *pNumGroups = subpath->rows; else *pNumGroups = estimate_num_groups(subroot, - get_tlist_exprs(subquery->targetList, false), + get_tlist_exprs(subroot->parse->targetList, false), subpath->rows, NULL, NULL); |