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

[Thomas Börkel]

Answering my own question:

After reading some MySQL performance tips, I changed the settings like
this (note that I also removed some):

key_buffer = 16M
max_allowed_packet = 1M
table_cache = 128
sort_buffer_size = 1M
net_buffer_length = 8K
query_cache_size = 16M
join_buffer_size = 1M
tmp_table_size = 128M
max_heap_table_size = 128M
thread_cache_size = 4

Scheduling is now very fast (0.2s). I think, it was mainly
tmp_table_size and max_heap_table_size...

Max. memory usage according to mysqltuner.pl is 629 MB, which sounds
good to me.

On 05.05.2013 00:15, Thomas Börkel wrote:
> HI!
> 
> On my production system, it takes very long to run the scheduler:
> 
> 2013-05-05 00:00:19.630711 I  Scheduled 740 items in 6.6 = 0.35 match +
> 0.39 check + 5.88 place
> 
> This is much faster on my test system with similar MySQL settings. The
> test system has less channels, but the same guide data (for the existing
> channels):
> 
> 2013-05-04 20:35:04.849792 I  Scheduled 943 items in 0.9 = 0.00 match +
> 0.00 check + 0.88 place
> 
> Both systems have a pretty similar Core i5 processor.
> 
> In MythTV wiki, there is some tuning explained, but it talks about
> InnoDB engine.
> 
> Apparently, when I look at the mysql dump of my databases, I am using
> MyIsam engine.
> 
> I already ran the optimize database script. Also I followed advice from
> the mysqltuner.pl script.
> 
> Anything else I can try?
> 
> Running MythTV 0.26 from March 2013.
> 
> These are my settings:
> key_buffer = 64M
> max_allowed_packet = 8M
> table_cache = 300
> sort_buffer_size = 48M
> net_buffer_length = 8M
> query_cache_type = 1
> query_cache_size = 32M
> join_buffer_size = 1M
> tmp_table_size = 64M
> max_heap_table_size = 64M
> thread_cache_size = 4
> key_buffer_size = 64M
> query_cache_limit = 8M
> 
> Thanks!
> 
> Thomas
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