From: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: pgsql-performance@postgresql.org
Subject: Re: Kill a session
Date: Wed, 12 Jul 2006 19:04:04 +0200
Message-ID: <20060712170404.GA27392@uio.no> (raw)
In-Reply-To: <44B51896.1000808@modgraph-usa.com>
References: <6BCB9D8A16AC4241919521715F4D8BCEA0FAE8@algol.sollentuna.se>
<44B51896.1000808@modgraph-usa.com>
On Wed, Jul 12, 2006 at 08:43:18AM -0700, Craig A. James wrote:
>> Then you killed the wrong backend...
>> No queries run in postmaster. They all run in postgres backends. The
>> postmaster does very little actual work, other than keeping track of
>> everybody else.
>
> It turns out I was confused by this: ps(1) reports a process called
> "postgres", but top(1) reports a process called "postmaster", but they both
> have the same pid. I guess postmaster replaces its own name in the process
> table when it's executing a query, and it's not really the postmaster even
> though top(1) calls it postmaster.
>
> So "kill -15 <pid>" is NOT killing the process -- to kill the process, I
> have to use signal 9. But if I do that, ALL queries in progress are
> aborted. I might as well shut down and restart the database, which is an
> unacceptable solution for a web site.
I don't follow your logic here. If you do "kill -15 <pid>" of the postmaster
doing the work, the query should be aborted without taking down the entire
cluster. I don't see why you'd need -9 (which is a really bad idea anyhow)...
> I'm back to my original question: How do you kill a runaway query without
> bringing down the whole database? Is there really no answer to this?
Kill it with -15. If you're worried about your CGI scripts, use sudo or some
sort of client/server solution.
/* Steinar */
--
Homepage: http://www.sesse.net/
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To: pgsql-performance@postgresql.org
Cc: sgunderson@bigfoot.com
Subject: Re: Kill a session
In-Reply-To: <20060712170404.GA27392@uio.no>
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