Re: notification: pg_notify ?

From: Mikhail Terekhov <terekhov(at)emc(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Neil Conway <nconway(at)klamath(dot)dyndns(dot)org>
Subject: Re: notification: pg_notify ?
Date: 2002-04-03 15:03:01
Message-ID: 3CAB19A5.3040103@emc.com
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Tom Lane wrote:


> There is a very significant performance problem with LISTEN/NOTIFY
> via pg_listener: in any application that generates notifications at
> a significant rate, pg_listener will accumulate dead tuples at that
> same rate, and we will soon find ourselves wasting lots of time
> scanning through dead tuples. Frequent VACUUMs might help, but the

That's unfortunate, may be if backend could reuse tuple on updates could help?

> whole thing is really quite silly: why are we using a storage mechanism
> that's designed entirely for *stable* storage of data to pass inherently
> *transient* signals? If the system crashes, we have absolutely zero

Because there is no other easy way to guarantee message delivery?

> interest in the former contents of pg_listener (and indeed need to go
> to some trouble to get rid of them).

There is no free beer :)

Regards,
Mikhail Terekhov

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