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From:Aleksandar Skodric Date:March 28 2008 3:43pm
Subject:Problems with unauthenticated user and DB slowing down
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Hi all,

I am having problems with the following issue.

Since couple of days ago, we got signs from our customers that website
'feels' very slow.
One of our tests is IQ test. For this one, timing is crucial and it is
unacceptable that test takes longer (because of slow site) - as it working
as a disadvantage for the one who is taking test.

We have following configuration:
Load balancer
|                  |
www1         www2

Both www1 and www2 are same hardware. On both is apache, with mysql:
www1:~# mysql --help
mysql  Ver 14.12 Distrib 5.0.32, for pc-linux-gnu (i486) using readline 5.2

www1 = master DB;
www2 = slave DB;

What I have noticed is that DB goes slow, there are few, sometimes many
(20+) unauthenticated user in process list.
They hang there for couple of seconds, then disappear. They are in state of
'connecting' and with action 'login'. They never establish connection
however.

I have checked:

1. ddos (could not find anything to point that way);
2. DNS resolving (as Google pointed that to be an issue); - no DNS problems,
both server can resolve nice and fast. I have also started both DB servers
with --skip-resolving but again, it did not help.

So, when these unauthenticated users come - the whole database goes real
slow for a few moments.

Has anyone had these issues? Any tips?

Cheers!

-- 
Met vriendelijke groeten / With kind regards,

Aleksandar Škodrić
MAS Coders / BEO Coders

Wijenburglaan 149
6825 CG Arnhem
The Netherlands
tel: +31 (0) 26 - 7113810
mob: +31 (0)62 - 6965820
fax: +31 (0)84 - 7369698
email: info@stripped
http://www.mascoders.nl
Trade register: NL-30173044
Thread
Problems with unauthenticated user and DB slowing downAleksandar Skodric28 Mar
  • Re: Problems with unauthenticated user and DB slowing downMichael Dykman28 Mar