[mythtv-firehose] mythtv/new-logging commit: b4d96b4c4 by Michael T. Dean (sphery)

[MythTV]

      Author:  Michael T. Dean <mdean at mythtv.org>
 Change Date:  2011-05-29T17:49:57-07:00
   Push Date:  2011/05/29 17:50:48 -0700
  Repository:  mythtv
      Branch:  new-logging
New Revision:  b4d96b4c4c37e5195affaf0d0662b4ab71c47c92
   Changeset:  https://github.com/MythTV/mythtv/commit/b4d96b4c4

Log:

Try to improve row counting performance for logging.

Since InnoDB engine doesn't store the row count for tables, like MyISAM
does, try to improve the performance of the count query.  By counting
id, the optimizer should choose to use the primary index.  At this
point, I'm not forcing it, but if it's found to help for InnoDB users,
we can do so later.

See:
http://www.cloudspace.com/blog/2009/08/06/fast-mysql-innodb-count-really-fast/
http://www.mysqlperformanceblog.com/2007/04/10/count-vs-countcol/

Modified:

   mythtv/programs/mythbackend/housekeeper.cpp