Comments on: Simple MySQL Proxy Failover

By: val

val — Sat, 05 Jun 2010 05:55:40 +0000

I’m having an issue using this script. I have my setup as two mysqld servers with master-master replication. When I unplug the network cable to master1 the mysql-proxy takes 3 minutes to failover to master2 and only marks master1 into state=2 (down) for 4 seconds. Then it ‘wakes it up’ again to state=0 (unknown). Upon the next query it takes another 3 minutes to fail (3 minutes because of the tcp timeout?) back to state=2 and then the whole cycle stars over again.

Why would it try to wake up the master1 after 4 seconds? What if the master1 machine goes down for the entire night, shouldn’t it just keep it down until it can be fixed? It would be fine if it didn’t hang for 3 minutes, but using this with web applications those 3 minutes is unacceptable.

Am I doing it wrong?

By: Diego

Diego — Tue, 16 Jun 2009 16:26:21 +0000

Hi Kyle,

This has been fixed on 0.7.0 (we have binaries available for 0.7.1 here http://dev.mysql.com/downloads/mysql-proxy/

Thanks

By: Kyle

Kyle — Tue, 16 Jun 2009 15:04:33 +0000

We had the same issue with 0.6.1 and rolled back to 0.6.0. 0.6.1 basically broke load balancing.

By: Sheeri Cabral

Sheeri Cabral — Tue, 03 Feb 2009 21:27:24 +0000

Erol,

Having the *exact* error would be useful. However, try doing a

telnet 192.168.100.21 3306

from the proxy machine to see if you can connect to the backend.

Also, you are aware that the proxy sits on port 4040 by default, right? So to connect you have to do:

mysql -h proxyserver -u user -p -P4040

By: Erol

Erol — Mon, 26 Jan 2009 20:01:40 +0000

Thanks fr this snippet of code.
One problem when I roll it out Im getting connection refused even though the proxy admin shows both backends

I start it with this:

/usr/local/sbin/mysql-proxy –proxy-lua-script=/opt/scripts/failover.lua –proxy-backend-addresses=192.168.100.21:3306 –proxy-backend-addresses=192.168.100.20:3306

The failover.lua is your code?
Any ideas what may cause this?

By: YoungWoo Kim

YoungWoo Kim — Tue, 01 Apr 2008 02:02:29 +0000

Sheeri,
Thanks for your advice.

So, I tested mysql-proxy 0.6.0.

As a result, It works fine with 0.6.0. :-)

In my case, I have two mysql servers with master-master replication scheme.

I think, mysql-proxy(0.6.1) does not recognize backends status(UP or DOWN).

Thanks.

Regards,
yw kim.

By: Sheeri Cabral

Sheeri Cabral — Mon, 31 Mar 2008 16:58:07 +0000

YoungWoo — I’m using

mysql-proxy-0.6.0-solaris10-x86_64

Can you give more details on how it does not work? ie, are you getting a syntax error with Lua, or are you finding that it does not work with failover? If that’s the case, what’s the behavior you’re seeing — are you seeing it do round-robin load balancing? Have you set up 2 backend servers with the –proxy-addresses startup option to mysql-proxy?

By: YoungWoo Kim

YoungWoo Kim — Mon, 31 Mar 2008 16:18:26 +0000

Hi Sheeri .
Thanks for your posting.
I got a Problem. It does not work mysql-proxy 0.6.1 on RHEL4.
Which version of mysql-proxy do you use for testing your lua script?

Thanks.

yw kim.