[mythtv] Scheduler needs table keys?

[f-myth-users at media.mit.edu]

    > Date: Sat, 27 Jan 2007 23:47:32 -0500
    > From: Brian Schott <bschott at east.isi.edu>

    > 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.

I'm one of the OP's on this issue, and my DB gets optimized daily.
That ain't it.  The problem is that the scheduler is holding locks
required to empty the ivtv buffers.

    > 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...).

I've got continuous "-v all" backend and frontend logs from the day I
started running Mythtv (about about 14 months ago).  I started seeing
IOBOUND errors after only a month, although I didn't notice them in
the logs for some months after that.  So it's not the size of
oldrecorded.

(Granted, I also had my DB on the same spindle as the recordings, and
I had it using the default Ubuntu Breezy settings and not the "big
database" settings some have mentioned [details on request], and
changing those helped a little---but not enough.)