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From:Morgan Tocker Date:June 2 2014 3:40pm
Subject:Re: SHOW FULL COLUMNS QUERIES hogging my CPU
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Hi Jatin,

On Jun 2, 2014, at 7:56 AM, Jatin Davey <jashokda@stripped> wrote:

> I found this blog while trying to find a fix for my problem. Thought it might be
> useful to share.
> 
> Here it is:
> 
> http://whirlpool.net.au/blog/5

To confirm - did you manage to fix your problem?

I was about to comment that it looks like queries generated by an ORM or connector.  It
looks like from your version string you have an MySQL enterprise, may I suggest creating
a ticket with support?

Regarding your most recent reply:

> All the "SHOW FULL COLUMN" queries that we do on the respective tables are very small
> tables. They hardly cross 50 rows. Hence that is the reason whenever these queries are
> made i can see high cpu usage in %user_time. If it were very large tables then the cpu
> would be spending lot of time in waiting for I/O as the databases reads would have to do a
> lot of I/O to read the data from the disks.

If it helps - I believe performance should be similar with large tables, since in the case
of big table or small table, what is accessed here should just be meta data.

Earlier versions of MySQL could rebuild InnoDB statistics on some SHOW commands (I’m
not sure about SHOW FULL COLUMN), but this is now disabled by default:
http://dev.mysql.com/doc/refman/5.6/en/innodb-parameters.html#sysvar_innodb_stats_on_metadata

- Morgan
Thread
SHOW FULL COLUMNS QUERIES hogging my CPUJatin Davey2 Jun 2014
  • Re: SHOW FULL COLUMNS QUERIES hogging my CPUReindl Harald2 Jun 2014
    • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJatin Davey2 Jun 2014
      • Re: SHOW FULL COLUMNS QUERIES hogging my CPUMichael Dykman2 Jun 2014
        • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJatin Davey2 Jun 2014
      • Re: SHOW FULL COLUMNS QUERIES hogging my CPUSinger Wang2 Jun 2014
        • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJatin Davey2 Jun 2014
          • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJatin Davey2 Jun 2014
            • Re: SHOW FULL COLUMNS QUERIES hogging my CPUMorgan Tocker2 Jun 2014
              • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJatin Davey3 Jun 2014
          • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJohan De Meersman2 Jun 2014
            • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJohan De Meersman3 Jun 2014
              • Re: SHOW FULL COLUMNS QUERIES hogging my CPUJatin Davey3 Jun 2014