[mythtv] Scheduler needs table keys?

Chris Pinkham cpinkham at bc2va.org
Sun Jan 28 04:28:55 UTC 2007


* On Sun Jan 28, 2007 at 02:11:22PM +1000, Paul Andreassen wrote:
> I noticed Chris Pinkham mention it takes 19 seconds for a schedule run, mine 
> takes under a second.  Why is that?  Are some "Recording Schedules" more 
> complex with better guide information.  If so, are there extra keys we could 
> add to speed it up?

There are a few things that can make big differences:

MySQL version (mine is 3.32.54 I believe, I have tested but swiched to 5.x)
Number of recording schedules (84 for me)
Number of channels defined (87)
Number of days worth of data (12)
Types of scheduled recordings (any/any is worse than exact time/channel)
    My breakdown looks like this:
       1 Timeslot Record
      12 Channel Record
      66 All Record (any time any channel)
       1 Weekslot Record
       1 Find One
       1 Find Daily
       1 Find Weekly

Then there are other things that our out of Myth's control that also
affect the speed, such as the CPU speed, remote vs local database, etc..

As a test, I just changed all my "All Record" entries to "Channel Record"
on my development system and my scheduler runtime went from 17 seconds
down to 12 seconds.  I then changed all the "Channel Record" items to
"Timeslot Record" and the runtime went down to 6 seconds.  I did multiple
runs of each of these to make sure it wasn't cached data that was causing
the speedup.  I deleted 30 of the now "Timeslot Record" entries to drop me
to a total of 54 scheduled recordings and the scheduler runtime went down
to 3 seconds.

So from this quick test, you can see how drastic the differences can be
in different people's scheduler runtimes based solely on their types of
scheduled recordings and the number of each.

--
Chris


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