From 097b6440066cb29a7a4ca769a3717ea0ebde6329 Mon Sep 17 00:00:00 2001 From: Sergey Petrunya Date: Wed, 19 Feb 2014 17:45:33 +0400 Subject: [PATCH] MDEV-5600: Wrong result on 2nd execution of PS depending on the length of the query - Item_direct_view_ref didn't clear its pointer to item_equal in ::cleanup. - Some Item_direct_view_ref objects have statement lifetime (i.e. they survive across multiple EXECUTE commands). Item_equal objects live only for the duration of one EXECUTE. This caused Item_direct_view_ref to have a stale pointer, which could cause all sorts of effects. (In this bug's testcase it was pointing to the wrong Item_equal, causing wrong query result) - Fixed by doing what Item_field::cleanup() does - don't keep item_equal pointer value. - There is no testcase because the only testcase I've got is highly fragile (e.g. the bug will not show up if @@datadir is of the wrong length). --- sql/item.h | 1 + 1 file changed, 1 insertion(+) diff --git a/sql/item.h b/sql/item.h index 58abc42dd80..80f8ef966bb 100644 --- a/sql/item.h +++ b/sql/item.h @@ -3103,6 +3103,7 @@ public: void cleanup() { null_ref_table= NULL; + item_equal= NULL; Item_direct_ref::cleanup(); } };