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Re: atrocious update performance

From: "Aaron Werman" <awerman2(at)hotmail(dot)com>
To: "Rosser Schwarz" <rschwarz(at)totalcardinc(dot)com>
Cc: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: atrocious update performance
Date: 2004-03-17 03:25:16
Message-ID: Law10-OE28zi95HfqR7000142f8@hotmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
Quick observations:

1. We have an explanation for what's going on, based on the message being
exactly 666 lines long :-)
2. I'm clueless on the output, but perhaps Tom can see something. A quick
glance shows that the strace seemed to run 27 seconds, during which it did:
  count| call
  -------|---------
      84 | _llseek
      40 | brk
      54 | close
      88 | open
      63 | read
in other words, nothing much (though it did *a lot* of opens and closes of
db files to do nothing ).

Can you do another strace for a few minutes against the actual update query
adding the -c/-t options and control-c out?

----- Original Message ----- 
From: "Rosser Schwarz" <rschwarz(at)totalcardinc(dot)com>
To: "'Tom Lane'" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <pgsql-performance(at)postgresql(dot)org>
Sent: Tuesday, March 16, 2004 7:20 PM
Subject: Re: [PERFORM] atrocious update performance


while you weren't looking, Tom Lane wrote:

[trace]

`strace -p 21882` run behind the below query and plan ... below that.

# explain update account.cust set prodid = tempprod.prodid, subprodid =
tempprod.subprodid where origid = tempprod.debtid;

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Subject: Re: rapid degradation after postmaster restart
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