MySQL Bugs: #34793: Failover/Balancing packet error

Bug #34793	Failover/Balancing packet error
Submitted:	24 Feb 2008 20:17	Modified:	17 Aug 2009 15:19
Reporter:	Paul Freeman	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Proxy: Core	Severity:	S1 (Critical)
Version:	0.61 & Trunk r369	OS:	Linux (2.6.23-gentoo-r8)
Assigned to:	MC Brown	CPU Architecture:	Any
Tags:	2.6.23, amd64, balance, failover, gentoo, linux, regression, x86_64

Description:
Running the proxy in standard balance/failover mode as described at http://forge.mysql.com/wiki/MySQL_Proxy#Load_Balancing_.26_Failover

quote: "Run your tests, shut down one of the backends and see how the MySQL Proxy sends all traffic to the one which is still alive."

shutting down a backend node renders the proxy unusable, causing it to reject all connections:

error from mysql-proxy stdout:
2008-02-24 20:06:38: (critical) plugin.c.3778: connect(<host a>:3306) failed: Connection refused

error from the connecting client:
mysql -h <proxy host> -p -u<user> --port 4040
ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 0

I have tested using 0.61 binaries from dev.mysql.com, 0.61 source tree and Trunk r369.

How to repeat:

using 0.61 binaries from dev.mysql.com or 0.61 source tree or Trunk r369.

./mysql-proxy \
 --proxy-backend-addresses=<host a>:3306 \
 --proxy-backend-addresses=<host b>:3308 

stop the mysqld instance running on host a or host b and the proxy will no longer accept client connections:

error from mysql-proxy stdout:
2008-02-24 20:06:38: (critical) plugin.c.3778: connect(<host a>:3306) failed: Connection refused

error from the connecting client:
mysql -h <proxy host> -p -u<user> --port 4040
ERROR 2013 (HY000): Lost connection to MySQL server at 'reading initial communication packet', system error: 0

Suggested fix:
none known at time of posting.

Thank you for the report.

Verified as described.

Bug #36387 was marked as duplicate of this one.

Bug is not repeatable with Load Balancer.

Bug is not repeatable with current SVN sources.

Also it seems to be duplicate of bug #35295

Bug #39628 was marked as duplicate of this one.

Is this bug fixed under current svn trunk or work is still in progress.

Is a version of mysql-proxy with a fix for this issue publicly available anywhere ?

Verified fixed on 0.7.1

A note has been added to the 0.7.1 changelog: 

When using MySQL Proxy with multiple backends, the failure of one backend would cause proxy to disconnect all backends and stop routing requests.