MySQL Bugs: #35648: Agent should set it's own wait

Bug #35648	Agent should set it's own wait_timeout
Submitted:	28 Mar 2008 14:26	Modified:	13 Jan 2009 11:09
Reporter:	Johan Idrén	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Enterprise Monitor: Agent	Severity:	S3 (Non-critical)
Version:	1.2.1.8246	OS:	Any
Assigned to:	Jan Kneschke	CPU Architecture:	Any

Description:
If a system has a global wait_timeout lower than the general activity of the agent, the agent will be kicked out, the monitored server will log an error and Aborted_clients will step up one.

How to repeat:
mysql> set global wait_timeout=45;
Query OK, 0 rows affected (0.00 sec)

From log:
080328 12:16:59 [Warning] Aborted connection 154 to db: 'unconnected' user: 'root' host: 'localhost' (Got timeout reading communication packets)

Suggested fix:
Let the agent set wait_timeout to something higher than it's usual sleep time, for it's own connection

Can be worked around by setting wait_timeout to a higher value globally, but if it's set very low then it's probably set low to workaround other issues. Hence not a very good workaround.

The fix is in 2.0.0 already.

revno: 983
committer: jan@mysql.com
branch nick: mysql-lb-clean
timestamp: Fri 2008-08-15 18:00:06 +0200
message:
  "set wait_timeout = 30min" (fixes #35648) and made the whole connection setup "fatal" to make
  sure we never operate on the connection if it isn't initialized correctly

Verified fixed in agent build 2.0.0.7111.

An entry was added to the 2.0 changelog:

If a system had a global wait_timeout lower than the general activity of the agent, the agent was disconnected. The monitored server then logged an error and incremented Aborted_clients.