From 7a12894de11ab04b93c9e96359008386b3b41cbb Mon Sep 17 00:00:00 2001
From: Igor Babaev <igor@askmonty.org>
Date: Sat, 10 Jun 2017 16:39:39 -0700
Subject: Fixed the bug mdev12992.

When the SELECT query from a trigger that used a subquery
in its SELECT list was prepared the counter select_n_having_items
was incremented in the constructor Item::Item(THD *thd).
As a result each invocation of the trigger required more and more
memory for the ref_pointer_array for this SELECT.
Made sure that the counter st_select_lex::select_n_having_items
would be incremented only at the first execution of such trigger.
---
 mysql-test/t/trigger.test | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

(limited to 'mysql-test/t/trigger.test')

diff --git a/mysql-test/t/trigger.test b/mysql-test/t/trigger.test
index 83b6966c676..5c65e3dd13b 100644
--- a/mysql-test/t/trigger.test
+++ b/mysql-test/t/trigger.test
@@ -2676,3 +2676,27 @@ select trigger_name, action_order, created from information_schema.triggers
   where event_object_table = 't1' and trigger_schema='test';
 drop table t1;
 set time_zone= @@global.time_zone;
+
+--echo #
+--echo # MDEV-12992: Increasing memory consumption
+--echo               with each invocation of trigger
+--echo #
+
+--let $n= 20000
+
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1);
+CREATE TABLE t2 (b INT);
+CREATE TRIGGER tr 
+  AFTER UPDATE ON t1 FOR EACH ROW SELECT (SELECT b FROM t2) INTO @x;
+ 
+--disable_query_log
+--echo # Running $n queries
+while ($n)
+{
+    UPDATE t1 SET a = 2;
+    --dec $n
+}
+--enable_query_log
+ 
+DROP TABLE t1,t2;
-- 
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