postgrespro.git / summary / log / commit / refs

commit    1e871981823a68ec9e0174b652e8d27e05ce08bb
Author:   Alexander Korotkov <akorotkov@postgresql.org>
Date:     Mon Apr 15 17:20:43 2019 +0000

    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;


[parent: 3a45321a4917]