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

From James Mansion
Subject Re: LISTEN / NOTIFY performance in 8.3
Date
Msg-id 47C48F9E.7000505@mansionfamily.plus.com
Whole thread Raw
In response to Re: LISTEN / NOTIFY performance in 8.3  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: LISTEN / NOTIFY performance in 8.3
List pgsql-performance
Tom Lane wrote:
> read-modify-write type of operation it uses an exclusive lock, so only
> one can clear its pg_listener entry at a time.  The 'waiting' ones you
> are seeing are stacked up behind whichever one has the lock at the
> moment.  They shouldn't be waiting for long.
>
I certainly hadn't expected that to be the implementation technique -
isn't it smply that we need
a sngle flag per worker process and can set/test-and-clear with atomic
operations and then a
signal to wake them up?

Anyway - how hard would it be to install triggers on commit and
rollback?  Then we could write
our own mechanisms.

James


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