Re: Performance monitor signal handler

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Samuel Sieb <samuel(at)sieb(dot)net>, Jan Wieck <JanWieck(at)Yahoo(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Performance monitor signal handler
Date: 2001-03-17 17:10:37
Message-ID: 200103171710.MAA21495@candle.pha.pa.us
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> ... and a lot more load on the CPU. Same-machine "network" connections
> are much cheaper (on most kernels, anyway) than real network
> connections.
>
> I think all of this discussion is vast overkill. No one has yet
> demonstrated that it's not sufficient to have *one* collector process
> and a lossy transmission method. Let's try that first, and if it really
> proves to be unworkable then we can get out the lily-gilding equipment.
> But there is tons more stuff to do before we have useful stats at all,
> and I don't think that this aspect is the most critical part of the
> problem.

Agreed. Sounds like overkill.

How about a per-backend shared memory area for stats, plus a global
shared memory area that each backend can add to when it exists. That
meets most of our problem.

The only open issue is per-table stuff, and I would like to see some
circular buffer implemented to handle that, with a collection process
that has access to shared memory. Even better, have an SQL table
updated with the per-table stats periodically. How about a collector
process that periodically reads though the shared memory and UPDATE's
SQL tables with the information.

--
Bruce Momjian | http://candle.pha.pa.us
pgman(at)candle(dot)pha(dot)pa(dot)us | (610) 853-3000
+ If your life is a hard drive, | 830 Blythe Avenue
+ Christ can be your backup. | Drexel Hill, Pennsylvania 19026

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