[mythtv-users] Slow MySQL query after delete

[Matthew McClement]

Pat Pierce wrote:
*snip*
> 
> was being left at "0" when the system deleted the files out of the
> "deleted" group. After updating the table with "update oldrecorded
> set duplicate='1';", I decided to clean up all the duplicate entries
> in the table. I had several hundred
> 
> lines which were duplicate title and subtitle, so I copied the table
> to "oldrecorded_test" create table oldrecorded_test as select * from
> oldrecorded; and made a delete statement as follows: delete from
> oldrecorded_test T1 where starttime not in
*snip*

Unless I'm missing something, it doesn't look like you re-created the
indexes on the new table, so selects were likely resulting in a full
table scan.

Depending on how much time you have, you can usually figure out what's
causing the performance problems by turning on slow query logging in
MySQL and then running the queries manually, prefixed with EXPLAIN. The
output isn't hugely complicated but the manual is your best reference to
figuring out the
output(http://dev.mysql.com/doc/refman/5.0/en/using-explain.html).

Matt