[mythtv] Scheduler needs table keys?

[Brian Schott]

There are a couple of other possibilities:

1.  Are you regularly running mysqlcheck?  It is possible that the  
indexes will get out of whack unless they are rebuilt periodically.   
I'm using Debian packages, so it has a cron.weekly file to do this.

2. How big is the oldreccorded table (how long has mythtv been  
running)?  I suspect that the search for duplicates will get slow  
over time since it is doing string compares on on unindexed titles  
and descriptions (at least, I don't think they are indexed...).

---
Brian


On Jan 27, 2007, at 11:28 PM, Chris Pinkham wrote:

> * 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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