diff options
Diffstat (limited to 'src/backend/optimizer/util/var.c')
| -rw-r--r-- | src/backend/optimizer/util/var.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/src/backend/optimizer/util/var.c b/src/backend/optimizer/util/var.c index 5f736ad6c40..4a3d5c8408e 100644 --- a/src/backend/optimizer/util/var.c +++ b/src/backend/optimizer/util/var.c @@ -161,8 +161,13 @@ pull_varnos_walker(Node *node, pull_varnos_context *context) if (IsA(node, PlaceHolderVar)) { /* - * Normally, we can just take the varnos in the contained expression. - * But if it is variable-free, use the PHV's syntactic relids. + * A PlaceHolderVar acts as a variable of its syntactic scope, or + * lower than that if it references only a subset of the rels in its + * syntactic scope. It might also contain lateral references, but we + * should ignore such references when computing the set of varnos in + * an expression tree. Also, if the PHV contains no variables within + * its syntactic scope, it will be forced to be evaluated exactly at + * the syntactic scope, so take that as the relid set. */ PlaceHolderVar *phv = (PlaceHolderVar *) node; pull_varnos_context subcontext; @@ -170,12 +175,15 @@ pull_varnos_walker(Node *node, pull_varnos_context *context) subcontext.varnos = NULL; subcontext.sublevels_up = context->sublevels_up; (void) pull_varnos_walker((Node *) phv->phexpr, &subcontext); - - if (bms_is_empty(subcontext.varnos) && - phv->phlevelsup == context->sublevels_up) - context->varnos = bms_add_members(context->varnos, phv->phrels); - else - context->varnos = bms_join(context->varnos, subcontext.varnos); + if (phv->phlevelsup == context->sublevels_up) + { + subcontext.varnos = bms_int_members(subcontext.varnos, + phv->phrels); + if (bms_is_empty(subcontext.varnos)) + context->varnos = bms_add_members(context->varnos, + phv->phrels); + } + context->varnos = bms_join(context->varnos, subcontext.varnos); return false; } if (IsA(node, Query)) |