List:General Discussion« Previous MessageNext Message »
From:nigel wood Date:August 27 2007 8:27pm
Subject:Re: servers full potential / FT searches locking tables
View as plain text  
Justin wrote:
> Sometimes I get about 300 connections to the server, all are selects 
> and all select and get the data returned but the connection doesn't go 
> away and the website doesn't load up.. usually if there is a lock, the 
> selects wait 2-3 secs and build up, but once unlocked the queries all 
> are performed and then go away.. and the sites load fine.. 3 times 
> today this has happened and I'm trying to figure out what could be the 
> cause of it.  if I restart MySQL everything is good.
>
> Anyone have any ideas or any ideas on how I can trace where the 
> culprit would be..
>
> it's a LAMP backend..
>
>
Are you classing insert...select or create table....select as selects? 
They have very different locking effects.
Is the database in replication? if so is it a master or slave?
Do you have NFS mounts anywhere on the database server?
Are you using exclusively innodb tables? if not the source is probably 
table contention.
Get a couple of 'show full processlist', 'show innodb status'  query 
outputs during the lockups and run vmstat 1 -S M in another terminal. 
With the outputs from both you've something to work with.

Nigel Wood
Thread
servers full potential / FT searches locking tablesJustin27 Aug
  • Re: servers full potential / FT searches locking tablesJay Pipes27 Aug
    • Re: servers full potential / FT searches locking tablesRolando Edwards27 Aug
      • Re: servers full potential / FT searches locking tablesJay Pipes27 Aug
        • Re: servers full potential / FT searches locking tablesJustin27 Aug
          • Re: servers full potential / FT searches locking tablesnigel wood27 Aug
    • Re: servers full potential / FT searches locking tablesJustin27 Aug
  • Re: servers full potential / FT searches locking tablesMathieu Bruneau28 Aug
    • Re: servers full potential / FT searches locking tablesJustin28 Aug
      • Re: servers full potential / FT searches locking tablesMichael Dykman28 Aug
        • Re: servers full potential / FT searches locking tablesJustin28 Aug
        • Re: servers full potential / FT searches locking tablesKen Peng29 Aug
          • Re: servers full potential / FT searches locking tablesMichael Dykman30 Aug
            • Re: servers full potential / FT searches locking tablesKen Peng30 Aug
              • Re: servers full potential / FT searches locking tablesMichael Dykman30 Aug
        • Re: servers full potential / FT searches locking tablesJustin1 Sep
          • Re: servers full potential / FT searches locking tablesJustin3 Sep
            • Re: servers full potential / FT searches locking tablesBaron Schwartz3 Sep
              • Re: servers full potential / FT searches locking tablesJustin4 Sep
                • Memory Issue would someone confirmJustin4 Sep
                  • Re: Memory Issue would someone confirmJustin4 Sep