From 1f42d35a1d6144a23602b2c0bc7f97f3046cf890 Mon Sep 17 00:00:00 2001 From: Alvaro Herrera Date: Wed, 12 Aug 2020 15:33:36 -0400 Subject: [PATCH] BRIN: Handle concurrent desummarization properly If a page range is desummarized at just the right time concurrently with an index walk, BRIN would raise an error indicating index corruption. This is scary and unhelpful; silently returning that the page range is not summarized is sufficient reaction. This bug was introduced by commit 975ad4e602ff as additional protection against a bug whose actual fix was elsewhere. Backpatch equally. Reported-By: Anastasia Lubennikova Diagnosed-By: Alexander Lakhin Discussion: https://postgr.es/m/2588667e-d07d-7e10-74e2-7e1e46194491@postgrespro.ru Backpatch: 9.5 - master --- src/backend/access/brin/brin_revmap.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/src/backend/access/brin/brin_revmap.c b/src/backend/access/brin/brin_revmap.c index e8b8308f82..35746714a7 100644 --- a/src/backend/access/brin/brin_revmap.c +++ b/src/backend/access/brin/brin_revmap.c @@ -282,10 +282,17 @@ brinGetTupleForHeapBlock(BrinRevmap *revmap, BlockNumber heapBlk, /* If we land on a revmap page, start over */ if (BRIN_IS_REGULAR_PAGE(page)) { + /* + * If the offset number is greater than what's in the page, it's + * possible that the range was desummarized concurrently. Just + * return NULL to handle that case. + */ if (*off > PageGetMaxOffsetNumber(page)) - ereport(ERROR, - (errcode(ERRCODE_INDEX_CORRUPTED), - errmsg_internal("corrupted BRIN index: inconsistent range map"))); + { + LockBuffer(*buf, BUFFER_LOCK_UNLOCK); + return NULL; + } + lp = PageGetItemId(page, *off); if (ItemIdIsUsed(lp)) {