Bug #26240 Creating a trigger on a locked table hangs the session

• Submitted: 9 Feb 2007 21:42
• Modified: 12 Feb 2007 7:33
• Reporter: Giuseppe Maxia
• Status: Duplicate
• Category: MySQL Server: Locking
• Severity: S2 (Serious)
• Version: 5.0.36,5.1.15
• OS: Linux (Linux, Mac OS X)
• CPU Architecture: Any
• Tags: locking, triggers

[9 Feb 2007 21:42] Giuseppe Maxia

Description:
If you lock a table and then try to create a trigger, the session hangs.

   DROP TABLE IF EXISTS t1;
   CREATE TABLE t1 (i int);
   LOCK TABLE t1 WRITE;
   create trigger t1_bi before insert on t1 for each row set @a:=1;

After these commands, the session is locked for its own user, who can't unlock it.

This can be related to bug#23713  

How to repeat:
--disable_warnings
   DROP TABLE IF EXISTS t1;
--enable_warnings
   CREATE TABLE t1 (i int) engine=myisam;
   LOCK TABLE t1 WRITE;
   create trigger t1_bi before insert on t1 for each row set @a:=1;

Suggested fix:
Perhaps forbidding the trigger creation when a table is locked?

[12 Feb 2007 7:33] Giuseppe Maxia

This bug is fixed in 5.0 by the same patch issued for bug#23713
 
(http://lists.mysql.com/commits/19659)

Changing the status to duplicate.