[mythtv-users] HowTo tune MySQL for schedule time and in general?

[Gary Buhrmaster]

On Sat, May 4, 2013 at 11:54 PM, Thomas Börkel <thomas at boerkel.de> wrote:
>
> Answering my own question:
.....
> Scheduling is now very fast (0.2s). I think, it was mainly
> tmp_table_size and max_heap_table_size...

The scheduler BUSQ (Big Ugly Scheduler Query) can
end up needing a large temporary result, depending on
the usual suspects (size/number of sources, channels,
recordings, recorded, etc.)  For a dedicated MythTV MySQL
DB, increasing the limit even further than 128M could mitigate
against a future surprise (since it seems that your previous
64M was not enough, it is not clear how close to 128M you
are currently at).  Note that one can also use tmpfs for the
/tmp filesystem (and some distro's are moving to that
paradigm) which can also mitigate against using disk i/o for
the temp tables, and since it is "the future", it is likely to
hide the poor defaults of MySQL for the tmp_table_size,
and a number of other tunables, which were apparently
chosen in the days where 640k was enough for anyone :-)

Gary