Re: Long running queries degrade performance

From: Mike Nolan <nolan(at)gw(dot)tssi(dot)com>
To: chris(dot)kratz(at)vistashare(dot)com (Chris Kratz)
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Long running queries degrade performance
Date: 2004-04-16 20:25:12
Message-ID: 200404162025.i3GKPDe4013710@gw.tssi.com
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> Fairly sure, when it is happening, postgres usually is taking up the top slots
> for cpu usage as reported by top. Perhaps there is a better way to monitor
> this?

Given the intermittent nature of the problem and its relative brevity
(5-10 seconds), I don't know whether top offers the granularity needed to
locate the bottleneck.

> likely you have a situation where something else is happening which blocks
> the current thread.

It happens on my development system, and I'm the only one on it. I know
I've seen it on the production server, but I think it is a bit more
common on the development server, though that may be a case of which system
I spend the most time on. (Also, the production server is 1300 miles away
with a DSL connection, so I may just be seeing network delays some of
the time there.)

> Both of these were triggered by users double clicking links in our
> web app and were fixed by a better implementation. Perhaps something like
> that is causing what you are seeing.

My web app traps double-clicks in javascript and ignores all but the first one.
That's because some of the users have mice that give double-clicks even
when they only want one click.
--
Mike Nolan

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