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From:Andrés Tello Date:October 3 2011 1:58pm
Subject:Re: 4 minute slow on select count(*) from table - myisam type
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have you tried

select count(yourindex) instead of select count(*) ?


On Mon, Oct 3, 2011 at 7:53 AM, Joey L <mjh2000@stripped> wrote:

> Thanks for the input -
> 1. I will wait 48 hours and see what happens.
> 2. can you tell me what are some performance tests I can do to help me
> better tune my server ?
> 3. I am concerned about this table : | w6h8a_sh404sef_urls
> |
> MyISAM |      10 | Dynamic    | 8908402 |            174 |  1551178184 |
>  281474976710655 |   2410850304 |         0 |        8908777 | 2011-09-22
> 11:16:03 | 2011-10-02 21:17:20 | 2011-10-02 10:12:04 | utf8_general_ci   |
>  NULL |                |                                   |
> what can I do to make it run faster - i did not write the code...but need
> to
> optimize server to handle this table when it gets larger.  It is used for
> url re-writes - so it has a lot of urls.
> thanks
> mjh
>
> On Mon, Oct 3, 2011 at 12:38 AM, Bruce Ferrell <bferrell@stripped
> >wrote:
>
> >
> > The meaning is:
> >
> > increase max_connections
> > reduce wait_timeout
> > -- 28800 is wait 8 hours before closing out dead connections
> > same for interactive_timeout
> >
> >
> > increase key_buffer_size (> 7.8G) increase join_buffer_size
> > -- This keeps mysql from having to run to disk constantly for keys
> > -- Key buffer size / total MyISAM indexes: 256.0M/7.8G
> > -- You have a key buffer of 256M and 7.8G of keys
> >
> > join_buffer_size (> 128.0K, or always use indexes with joins)
> > Joins performed without indexes: 23576 of 744k queries.
> > -- You probably want to look at the slow query log.  Generalize the
> queries
> > and the do an explain on the query.  I have seen instances where a query
> I
> > thought was using an index wasn't and I had to re-write... with help from
> > this list :-)  Thanks gang!
> >
> >
> > increase tmp_table_size (> 16M)
> > increase max_heap_table_size (> 16M)
> > -- When making adjustments, make tmp_table_size/max_heap_table_size equal
> >
> > increase table_cache ( > 1k )
> > -- Table cache hit rate: 7% (1K open / 14K opened)
> > -- Increase table_cache gradually to avoid file descriptor limits
> >
> > All of the aside, you need to let this run for at least 24 hours. I
> > prefer 48 hours.  The first line says mysql has only been running 9
> > hours.   You can reset the timeouts interactivly by entering at the
> > mysql prompt:
> >
> > set global wait_timeout=<some value>
> >
> > You can do the same for the interactive_timeout.
> >
> > Setting these values too low will cause long running queries to abort
> >
> >
> > On 10/02/2011 07:02 PM, Joey L wrote:
> > > Variables to adjust:
> > > >     max_connections (> 100)
> > > >     wait_timeout (< 28800)
> > > >     interactive_timeout (< 28800)
> > > >     key_buffer_size (> 7.8G)
> > > >     join_buffer_size (> 128.0K, or always use indexes with joins)
> > > >     tmp_table_size (> 16M)
> > > >     max_heap_table_size (> 16M)
> > > >     table_cache (> 1024)
> >
> >
> > --
> > MySQL General Mailing List
> > For list archives: http://lists.mysql.com/mysql
> > To unsubscribe:    http://lists.mysql.com/mysql?unsub=1
> >
> >
>

Thread
4 minute slow on select count(*) from table - myisam typeJoey L2 Oct
  • Re: 4 minute slow on select count(*) from table - myisam typeAndrew Moore2 Oct
    • Re: 4 minute slow on select count(*) from table - myisam typeJoey L2 Oct
  • Re: 4 minute slow on select count(*) from table - myisam typeBruce Ferrell2 Oct
Re: 4 minute slow on select count(*) from table - myisam typeAndrew Moore2 Oct
  • Re: 4 minute slow on select count(*) from table - myisam typeJoey L3 Oct
    • Re: 4 minute slow on select count(*) from table - myisam typeJoey L3 Oct
      • Re: 4 minute slow on select count(*) from table - myisam typeBruce Ferrell3 Oct
        • Re: 4 minute slow on select count(*) from table - myisam typeJoey L3 Oct
          • Re: 4 minute slow on select count(*) from table - myisam typeAndrés Tello3 Oct
            • Re: 4 minute slow on select count(*) from table - myisam typeJoey L3 Oct
              • Re: 4 minute slow on select count(*) from table - myisam typeEric Bergen3 Oct
                • Re: 4 minute slow on select count(*) from table - myisam typeJoey L6 Oct
                  • Re: 4 minute slow on select count(*) from table - myisam typeJoey L6 Oct
                    • Re: 4 minute slow on select count(*) from table - myisam typeJohnny Withers6 Oct
                      • Re: 4 minute slow on select count(*) from table - myisam typeJoey L6 Oct
                        • Re: 4 minute slow on select count(*) from table - myisam typeJohnny Withers6 Oct
                        • Re: 4 minute slow on select count(*) from table - myisam typeJohan De Meersman6 Oct
                        • Re: 4 minute slow on select count(*) from table - myisam typeRik Wasmus6 Oct
                          • Re: 4 minute slow on select count(*) from table - myisam typeJoey L6 Oct
                            • Re: 4 minute slow on select count(*) from table - myisam typeAndrew Moore6 Oct
                              • Re: 4 minute slow on select count(*) from table - myisam typeAndrew Moore6 Oct
                                • Re: 4 minute slow on select count(*) from table - myisam typeJoey L6 Oct
                                  • Re: 4 minute slow on select count(*) from table - myisam typeMichael Dykman6 Oct
Re: 4 minute slow on select count(*) from table - myisam typeAndrew Moore6 Oct
  • Re: 4 minute slow on select count(*) from table - myisam typeJoey L6 Oct
Re: 4 minute slow on select count(*) from table - myisam typeJohnny Withers6 Oct
  • Re: 4 minute slow on select count(*) from table - myisam typeJohan De Meersman7 Oct
Re: 4 minute slow on select count(*) from table - myisam typeJan Steinman7 Oct
  • Re: 4 minute slow on select count(*) from table - myisam typeJoey L7 Oct
    • Re: 4 minute slow on select count(*) from table - myisam typeAndrew Moore7 Oct