[mythtv-users] Slow program listings and deleting

[Rob Willett (Mythtv)]

Nick,

Thanks for this. My comments are

Nick Morrott wrote:
>> 1) Should the table recordmatch be so large? Is 4,000 entries a lot?
> 
> I depends on how many recording rules you have, how many results they
> generate per video source, and how many video soures you have defined.
> Do you have any rules which return many results, such as genre
> searches, or are they specific to program titles? If you remove any
> rules which have been created recently, does performance revert to its
> previous level?

I do have a fair few recording rules. They are mostly one-offs for 
recording a film or something. No genre searches. I'll go through these 
and pull them out and see what happens.

>> 2) Should data be deleted from this table? if so how?
> 
> No. This should happen automatically during rescheduling and after
> listings updates.

Not sure what you mean here, you say no and then say it happens 
automatically. I think you mean that after a listing update from the DVB 
signal older programs are deleted.

> 
>> 3) What sizes are other peoples recordmatch tables?
> 
> I currently have 288 records in recordmatch, generated from 2 video
> sources and 54 recording rules.

Mmm....I have 4012 in this table. I will do 1) and see if this reduces.

> 
>> 4) Does the monster SQL statement above look familiar? Does it have form
>> as a slow query? Are there additional indexes that could be created? I
>> did an EXPLAIN on it, but it doesn't give me any real help.
> 
> You can check http://cvs.mythtv.org/trac/browser/trunk/mythtv/libs/libmythtv/dbcheck.cpp
> and cross-reference your installation's DBSchema version to ensure you
> have the intended indexes - if you have any missing you can recreate
> them.
> 

Thats the sort of thing I was after. I've had a look and will see if I 
can compare this to my schema.

>> 5) Any suggestions as to what to do?
> 
> Check your video sources/channels and make sure you do not have any
> extraneous channels/listings data in the database. I can't say whether
> upgrading to 0.20-fixes would help you out here.
> 

The video sources has one entry, so I suspect thats OK.

The channels table has 38 rows. Some of them (Teachers TV) will never be 
used. I will trim them down.