Re: App very unresponsive while performing simple update - Mailing list pgsql-performance

From Greg Stark
Subject Re: App very unresponsive while performing simple update
Date
Msg-id 87slmum3th.fsf@stark.xeocode.com
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In response to Re: App very unresponsive while performing simple update  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: App very unresponsive while performing simple update  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
Tom Lane <tgl@sss.pgh.pa.us> writes:

> Greg Stark <gsstark@mit.edu> writes:
> > What queries are those two processes executing? And what foreign keys do you
> > have on the product table or elsewhere referring to the product table? And
> > what indexes do you have on those columns?
>
> And what PG version is this?  Alvaro fixed the
> foreign-keys-take-exclusive-locks problem in 8.1 ...

Except I don't think this is taking an exclusive lock at all. The original
post had the deadlock detection fire on a SharedLock. I think the other
process is also an update and is holding an exclusive lock while also
trying to acquire a SharedLock for a foreign key column.

--
greg

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