David Geier <da...@swarm64.com> writes: > search_plan_tree() assumes that > CustomScanState::ScanState::ss_currentRelation is never NULL. In my > understanding that only holds for CustomScanState nodes which are at the > bottom of the plan and actually read from a relation. CustomScanState > nodes which are not at the bottom don't have ss_currentRelation set. I > believe for such nodes, instead search_plan_tree() should recurse into > CustomScanState::custom_ps.
Hm. I agree that we shouldn't simply assume that ss_currentRelation isn't null. However, we cannot make search_plan_tree() descend through non-leaf CustomScan nodes, because we don't know what processing is involved there. We need to find a scan that is guaranteed to return rows that are one-to-one with the cursor output. This is why the function doesn't descend through join or aggregation nodes, and I see no argument by which we should assume we know more about what a customscan node will do than we know about those. So I'm inclined to think a suitable fix is just - if (RelationGetRelid(sstate->ss_currentRelation) == table_oid) + if (sstate->ss_currentRelation && + RelationGetRelid(sstate->ss_currentRelation) == table_oid) result = sstate; regards, tom lane