[mythtv-users] Slow MySQL query after delete

jack snodgrass mrlinuxgroups at gmail.com
Sun Sep 2 12:56:17 UTC 2007


On 9/2/07, crs23 <pvr at groundhog.pair.com> wrote:
>
>
>  Deleting programs has been slow for me I think since I started using
> MythTV, but it's been getting worse and now it's pretty bad. I think I've
> tracked it down to a particularly slow SQL query and I'm hoping some one
> will have some advice for making it fast(er).
>
>  First, the backend seems to hold off on this query for a few seconds. I can
> usually manage to delete two programs before it kicks in. But when it does
> the frontend blocks waiting for the backend which itself blocks waiting for
> mysql.
>
>  The query takes around 35 to 40 seconds. It's a pretty complicated query.
> I've included it below but here I'll just mention it JOINs ten tables. Here
> are the EXPLAIN results. Sorry for the wide columns.


..stuff deleted....

.. I'm not sure I see the issues your having... you say that the query
takes 35 - 40
seconds, but the one you show says:

"10 rows in set (0.02 sec)"

I can past in that long-ass query you posted and it takes
68 rows in set (0.02 sec)
for me too.....

where / when / how exactly are you seeing thins query take 30+ seconds?

jack


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