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From:walter harms Date:June 13 2013 7:41am
Subject:Re: open files in mysqld 5.1.53
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Am 12.06.2013 12:33, schrieb Manuel Arostegui:
> 2013/6/12 walter harms <wharms@stripped>
> 
>>
>> Hi list,
>> i am trying to understand the incredible use of filepointers in our mysql
>> server (5.1.53).
>> under normal condition the server reports 10k-15k open files pointer.
>> I run a 'flush tables' every 2h to avoid problems, the number of
>> users/connections is constant
>> It is an automatic system but a few human users, a happy mix of myisam and
>> innodb tables running
>> with no problems on  mysqld 5.0 . But now sometimes i am
>> hit with an insane increase hitting the ceiling at 60k. I do not like the
>> idea to increase the
>> limit further because i do
>> not understand why this is happening (I seems to happen at random times).
>>
>> I am running out of idea what my cause the unexpected increase, any idea
>> what to watch ?
> 
> 
> I had a similar problem some years ago with 5.0.84. It was a database with
> thousand of tables (mostly in MyISAM).
> It turned to be the  --myisam-recover option in Debian init scripts (
> /usr/share/mysql/debian-start.inc.sh) . Obviously it's not a good idea to
> remove it, as if the server crashes, you will needed it.
> This used to be our db server after getting started:
> 
> dXX:~# find /proc/`cat /var/run/mysqld/mysqld.pid`/fd -follow -type f
> 2>/dev/null | wc -l
> 116810
> 
> This is what I saw at the time after removing that MyISAM check:
> 
> dXX:~# find /proc/`cat /var/run/mysqld/mysqld.pid`/fd -follow -type f
> 2>/dev/null | wc -l
> 10730
> 
> I would not recommend to keep this as a for-good-solution but a temporary
> one till you decide what to do. We migrated most of the tables to InnoDB
> (there was no reason to keep them as MyISAM, it was just legacy stuff). And
> these problems were gone.
> 
> I don't know if this can be your case, but this is what happened to us.
> 


Hello Manuel,
thx for your tip. We caught the problem when we moved to partitions. Strange is that
while testing the problem did not show up and even now we no clue why we experience
the sudden burst of use for file descriptors.

btw: i checked for that option and it seems that it is not set on the commandline
maybe it is hidden somewhere, since we use the mysql_safe wapper it should no be
but you never know.

re,
 wh



Thread
open files in mysqld 5.1.53walter harms12 Jun
  • Re: open files in mysqld 5.1.53Reindl Harald12 Jun
  • Re: open files in mysqld 5.1.53Manuel Arostegui12 Jun
    • Re: open files in mysqld 5.1.53walter harms13 Jun
      • Re: open files in mysqld 5.1.53Hartmut Holzgraefe13 Jun
        • Re: open files in mysqld 5.1.53walter harms13 Jun
        • Re: open files in mysqld 5.1.53Reindl Harald13 Jun