From 883dc0214a64c0923455bf30bfcc5f953e70af39 Mon Sep 17 00:00:00 2001 From: Tomas Vondra Date: Fri, 30 Dec 2022 19:44:48 +0100 Subject: [PATCH] Fix assert in BRIN build_distances When brin_minmax_multi_union merges summaries, we may end up with just a single range after merge_overlapping_ranges. The summaries may contain just one range each, and they may overlap (or be exactly the same). With a single range there's no distance to calculate, but we happen to call build_distances anyway - which is fine, we don't calculate the distance in this case, except that with asserts this failed due to a check there are at least two ranges. The assert is unnecessarily strict, so relax it a bit and bail out if there's just a single range. The relaxed assert would be enough, but this way we don't allocate unnecessary memory for distance. Backpatch to 14, where minmax-multi opclasses were introduced. Reported-by: Jaime Casanova Backpatch-through: 14 Discussion: https://postgr.es/m/YzVA55qS0hgz8P3r@ahch-to --- src/backend/access/brin/brin_minmax_multi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/src/backend/access/brin/brin_minmax_multi.c b/src/backend/access/brin/brin_minmax_multi.c index 389244b9c6c..73cc94de7bf 100644 --- a/src/backend/access/brin/brin_minmax_multi.c +++ b/src/backend/access/brin/brin_minmax_multi.c @@ -1335,7 +1335,11 @@ build_distances(FmgrInfo *distanceFn, Oid colloid, int ndistances; DistanceValue *distances; - Assert(neranges >= 2); + Assert(neranges > 0); + + /* If there's only a single range, there's no distance to calculate. */ + if (neranges == 1) + return NULL; ndistances = (neranges - 1); distances = (DistanceValue *) palloc0(sizeof(DistanceValue) * ndistances);