MySQL Bugs: #39603: MEM 2.0 does not fail on certain critical error

Bug #39603	MEM 2.0 does not fail on certain critical error
Submitted:	23 Sep 2008 15:32	Modified:	21 Jul 2009 10:45
Reporter:	Matthew Montgomery	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Enterprise Monitor: Agent	Severity:	S3 (Non-critical)
Version:	2.0.0.7017 ?	OS:	Any
Assigned to:	Kay Roepke	CPU Architecture:	Any
Tags:	mem_20_maint

Description:
Agent receives this critical error but does not terminate.

2008-09-23 09:35:02: (critical) agent_mysqld.c:139: mysql_real_query() failed: Can't find file: './mysql/inventory.frm' (errno: 13) (errno=1017)

How to repeat:
Set permissions on mysql.inventory table such that the agent user cannot access it.  Then restart the agent.

Suggested fix:
Make the agent handle the "critical" error with a shutdown.

As far as I can tell this is not a critical error, so the log level should be changed? It means that the agent is unable to get information from the *replication master* of the slave it is monitoring to help deduce the topology. However there are other sources of information for topology discovery to use.

Jan, any comment on how you end up in this branch? Is it *really* critical at this point? Can the agent tell that it doesn't have enough information to send up for discovery to complete without access to the *master* UUID?

Looks like the error-msg is also wrong. We should leave early here, yes.

Kay Roepke writes: 
------------------------------------------------------------
revno: 1411
committer: Kay Roepke <kay@sun.com>
branch nick: agent
timestamp: Thu 2009-07-09 18:33:33 +0200
message:
  Bug#39603/EM-3151: don't try to reconnect and execute queries when we are already in shutdown mode, avoid flooding the log with spurious error messages

Keith Russell writes: 
Patch installed in versions => 2.1.0.1076.

Diego Medina writes: 
Verified fixed on 2.1.0.1076

The agent does not shutdown on such a critical error, because it is not a critical error. It shows as critical because of the underlying log system we currently use.

Before, the agent would log the same error message several times, now it logs it only once.

An entry was added to the 2.1.0 changelog:

The Agent received a critical error but did not terminate as expected. The critical error generated was:

2008-09-23 09:35:02: (critical) agent_mysqld.c:139: mysql_real_query() failed: Can't find
file: './mysql/inventory.frm' (errno: 13) (errno=1017)