[Chugalug] damned if you do, damned if you don't

Ed King chevyiinova at bellsouth.net
Wed Oct 10 20:50:37 UTC 2012


I'm such a slacker...   it took me 2 months to install "innotop".   I just 
finished the installation and got it to connect.   Looks like the default screen 
shows db uptime, queries per second, and current sql statement executing on the 
main screen.   I hit "L" to get to the show-lock screen and wouldn't you know 
it, I don't have any locks right now (not complaining).





________________________________
From: Jason Brown <lists at masterforge.com>
To: chugalug at chugalug.org
Sent: Fri, August 17, 2012 12:05:37 PM
Subject: Re: [Chugalug] damned if you do, damned if you don't


The default timeout is 50 seconds,       thats a pretty long time for an insert 
or update. Are you sure you       can't trim that?
You might be better served tracking down the locking culprit and       fixing 
the root issue, that or upgrading to faster hardware.
This looks useful, 
http://www.xaprb.com/blog/2007/09/18/how-to-debug-innodb-lock-waits/        I 
have not used that exact method yet but now that I have found it       I plan 
to.

Anyway, here are some lines from some of my server configs that       affect 
innodb performance.

innodb_flush_method = O_DIRECT
This one is very hardware dependent, may help, may hurt: 
http://dev.mysql.com/doc/refman/5.1/en/innodb-parameters.html#sysvar_innodb_flush_method
 (We use to avoid double buffering as the article says).

innodb_flush_log_at_trx_commit = 2
Depends on your situation, reduces disk write load by a tiny       amount.

--Jason



On 08/17/2012 12:50 PM, Ed King wrote:

----- Original Message ----  sooooooo...  what magical incantations do you folks 
use in your my.cnf file to  avoid innodb locks yet still maintain transactional 
integrity?   did I stump the experts? ;)   I've tried increasing the lock wait 
timeout and I  even turned off the locks completely (or so I thought) but I 
still get an  occasional lock-wait timeout.  I don't see how I can make my 
transactions any  smaller than what they already are.     I was visiting my 
nephew last night when I asked if I could borrow a newspaper. "This is the 21st 
century." he said. "We don't waste money on newspapers. Here, you can borrow my 
iPad." I can tell you, that bloody fly never knew what hit it... 
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