The ungrouped zone-map aggregate ignores a WHERE that references no column, and returns rows heap does not #1435

Found by @OffgridwithJD reviewing #1429. Measured on PG17 and PG18 at default settings.

What happens

On a columnar table, an ungrouped aggregate whose WHERE references no column ignores that WHERE:

The plan shows Columnar Vectorized Aggregates: 3, with no gating Result above it. This is a wrong answer, not a performance issue.

Cause, as read in the code

src/columnar_vector.c builds the ungrouped node's quals with extract_actual_clauses(factRel->baserestrictinfo, false) (around line 1567). With pseudoconstant = false that drops the gating quals, so quals is NIL and needsScan is false. The node then answers from the zone maps alone. The node's own gating-qual refusal, further down (around line 1639), is never reached on that path.

The grouped node has the same refusal, and checks it before building its quals, which is why it isn't affected. An RLS policy with no column reference is planned as an ordinary Filter, and was measured safe.

Proposed fix

Refuse the ungrouped node when baserestrictinfo holds a pseudoconstant qual, before needsScan is decided, as the grouped node does. The test should be red first, in both twins: each of the three queries above against heap, plus a premise that a column-free WHERE which is true still gets the vectorized plan.

🤖 Generated with Claude Code