[mythtv-users] Slow MySQL query after delete

crs23 pvr at groundhog.pair.com
Wed Sep 5 04:30:39 UTC 2007

Victor Perez-2 wrote:
> IMHO the query is pretty quick but (at least in my case) returns a whole
> lot
> of information. I got 1168 rows back in 4 seconds but the data makes a
> 421K
> file. In my opinion the delay is from mythtv parsing through this huge
> dataset so we would need to find out why does it need that much
> information
> back on each row, program's primary key should be enough for mythtv to
> find
> the next program to record.

I have empirical evidence which I've posted that shows the query is not
quick for me.  I get over 3600 rows in about 30 seconds via the command line
mysql.  MythTV is not involved in that time.  Any performance improvement is
welcome, of course, but speeding up parsing the result of this query
probably won't be very significant on my box.

It's interesting you get about 1/3 the rows in 1/9 the time.  That suggests
a potential quadratic behavior in the query but two data points isn't much
to pin a hypothesis on.

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