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From:Hank Date:September 22 2011 7:51pm
Subject:Re: Slower performance with LOCK TABLES
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On Thu, Sep 22, 2011 at 3:11 PM, Hassan Schroeder <
hassan.schroeder@stripped> wrote:

> On Thu, Sep 22, 2011 at 11:51 AM, Hank <heskin@stripped> wrote:
> > Like I said, the problem is not just one particular SQL statement. It is
> > several dozen statements operating on tables with several hundred million
> > records.  The problem is that I am finding that when I use LOCK TABLES,
> > these queries run slower (please read my ORIGINAL post with all this
> > information).
>
> Wandering out my area of expertise here :-) but have you done any
> key cache tuning or are you running with the defaults?
>
> mysql> show variables like 'key_%';
>
> Also, what is the exact LOCK TABLE statement you're using?
>
>
No, I haven't done any key cache tuning, as that's out of my area of
expertise as well! I have 8GB of memory on this box, and I can go up to
12GB.

Here are the variables:

| key_buffer_size          | 402653184 |
| key_cache_age_threshold  | 300       |
| key_cache_block_size     | 1024      |
| key_cache_division_limit | 100       |

The lock statement is quite simple:

LOCK TABLE dest d write, source s read;

thanks.

Thread
Slower performance with LOCK TABLESHank22 Sep
  • Re: Slower performance with LOCK TABLESAntony T Curtis22 Sep
    • Re: Slower performance with LOCK TABLESHank22 Sep
Re: Slower performance with LOCK TABLESAntony T Curtis22 Sep
  • Re: Slower performance with LOCK TABLESHank22 Sep
    • Re: Slower performance with LOCK TABLESAnanda Kumar22 Sep
      • Re: Slower performance with LOCK TABLESHank22 Sep
        • Re: Slower performance with LOCK TABLESAnanda Kumar22 Sep
          • Re: Slower performance with LOCK TABLESHank22 Sep
            • Re: Slower performance with LOCK TABLESAnanda Kumar22 Sep
              • Re: Slower performance with LOCK TABLESHank22 Sep
                • Re: Slower performance with LOCK TABLESAnanda Kumar22 Sep
                • Re: Slower performance with LOCK TABLESJohan De Meersman23 Sep
                  • Re: Slower performance with LOCK TABLESHank23 Sep
                  • Re: Slower performance with LOCK TABLESHank23 Sep
                    • Re: Slower performance with LOCK TABLESJohan De Meersman26 Sep
                  • Re: Slower performance with LOCK TABLEShsv23 Sep
Re: Slower performance with LOCK TABLESHank22 Sep