From 1e871981823a68ec9e0174b652e8d27e05ce08bb Mon Sep 17 00:00:00 2001 From: Alexander Korotkov Date: Mon, 15 Apr 2019 20:20:43 +0300 Subject: [PATCH] Fix division by zero in _bt_vacuum_needs_cleanup() Checks inside _bt_vacuum_needs_cleanup() allow division by zero to happen when metad->btm_last_cleanup_num_heap_tuples == 0. This commit adjusts the expression so that no division by zero might happen. Reported-by: Piotr Stefaniak Discussion: https://postgr.es/m/DB8PR03MB5931C41F7787A95313F08322F22A0%40DB8PR03MB5931.eurprd03.prod.outlook.com Reviewed-by: Masahiko Sawada Backpatch-through: 11 --- src/backend/access/nbtree/nbtree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/backend/access/nbtree/nbtree.c b/src/backend/access/nbtree/nbtree.c index 7370379c6a..02fb352b94 100644 --- a/src/backend/access/nbtree/nbtree.c +++ b/src/backend/access/nbtree/nbtree.c @@ -835,7 +835,7 @@ _bt_vacuum_needs_cleanup(IndexVacuumInfo *info) prev_num_heap_tuples = metad->btm_last_cleanup_num_heap_tuples; if (cleanup_scale_factor <= 0 || - prev_num_heap_tuples < 0 || + prev_num_heap_tuples <= 0 || (info->num_heap_tuples - prev_num_heap_tuples) / prev_num_heap_tuples >= cleanup_scale_factor) result = true;