From: Alexander Barkov
Date: November 16 2010 7:28pm
Subject: Re: bzr commit into mysql-5.5-bugteam branch (bar:3121) Bug#57306
List-Archive: http://lists.mysql.com/commits/124077
Message-Id: <4CE2DB54.2000608@oracle.com>
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Hi Guilhem,

I've committed a new patch version:

http://lists.mysql.com/commits/124076


It fixes two small problems:

- with SHOW PROCESSLIST printing empty string instead of "NULL"
   in the Info column in some circumstances.


- Under heavy load the new test case failed with this diff:

--- 
/home/bar/mysql-bzr/mysql-5.5-bugteam.b57306/mysql-test/r/show_check.result 
2010-11-16 13:24:34.000000000 +0300
+++ 
/home/bar/mysql-bzr/mysql-5.5-bugteam.b57306/mysql-test/r/show_check.reject 
2010-11-16 21:18:03.000000000 +0300
@@ -1526,7 +1526,7 @@
  SHOW PROCESSLIST;
  Id	User	Host	db	Command	Time	State	Info
  ###	root	localhost	test	Query	###	###	SHOW PROCESSLIST
-###	root	localhost	test	Query	###	###	SELECT GET_LOCK('t',1000) AS 'σσσσ'
+###	root	localhost	test	Query	###	###	SET NAMES latin1
  SET NAMES utf8;
  SHOW PROCESSLIST;
  Id	User	Host	db	Command	Time	State	Info



This happened because "SHOW PROCESSLIST" in the default
thread could start before the background thread con1 changes its status
from "SET NAMES latin1" to "SELECT GET_LOCK('t',1000) AS 'σσσσ'".


So I added wait_condition as follows:

SET NAMES latin1;
--send SELECT GET_LOCK('t',1000) AS 'σσσσ';
--connection default
# Make sure con1 has switched from "SET NAMES" to "SELECT GET_LOCK"
let $wait_timeout= 10;
let $wait_condition= SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST 
WHERE INFO LIKE '%GET_LOCK%';
--source include/wait_condition.inc
--replace_column 1 ### 6 ### 7 ###
SHOW PROCESSLIST;