Re: LISTEN / NOTIFY performance in 8.3 - Mailing list pgsql-performance

From Tom Lane
Subject Re: LISTEN / NOTIFY performance in 8.3
Date
Msg-id 5576.1203795335@sss.pgh.pa.us
Whole thread Raw
In response to LISTEN / NOTIFY performance in 8.3  (Joel Stevenson <joelstevenson@mac.com>)
List pgsql-performance
Joel Stevenson <joelstevenson@mac.com> writes:
> I have an existing app that provides a producer / consumer type of
> queue and that uses the LISTEN / NOTIFY mechanism to signal the
> consumers of new items arriving in the queue.  The consumers then
> process these items and issue a notify to signal that they have been
> processed.  In the past issuing these notifications happened very
> quickly, now on 8.3 I'm seeing all of them taking over 300ms and many
> of them taking 1500ms or more!

That's strange, I would not have thought that listen/notify behavior
would change at all.  How are you measuring this delay exactly?
Can you put together a self-contained test case?

            regards, tom lane

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