Re: slow table updates - Mailing list pgsql-performance

From Reece Hart
Subject Re: slow table updates
Date
Msg-id 1058983630.7281.101.camel@tallac
Whole thread Raw
In response to slow table updates  (Reece Hart <rkh@gene.COM>)
List pgsql-performance
On Wed, 2003-07-23 at 10:47, Guthrie, Jeremy wrote:
Have you checked the sizes of your indexes?  You may need to rebuild them...

Multiply the relpages colum by 8192.

So, what does this tell me? I'm guessing that you're implying that I should expect 8192 keys per page, and that this therefore indicates the sparseness of the key pages. Guessing that, I did:

rkh@csb=> SELECT c2.relname, c2.relpages, c2.relpages*8192 as "*8192",
   43413476::real/(c2.relpages*8192) FROM pg_class c, pg_class c2, pg_index i
   where c.oid = i.indrelid AND c2.oid = i.indexrelid and c2.relname~'^p2th|^papro'
   ORDER BY c2.relname;

             relname             | relpages |   *8192    |      ?column?
---------------------------------+----------+------------+--------------------p2thread_p2params_id            |   122912 | 1006895104 | 0.0431161854174633p2thread_pmodel_id              |   123243 | 1009606656 | 0.0430003860830331paprospect2_redundant_alignment |   229934 | 1883619328 | 0.0230479032332376

What do you make of 'em apples?

Thanks,
Reece

-- 
Reece Hart, Ph.D.                       rkh@gene.com, http://www.gene.com/
Genentech, Inc.                         650/225-6133 (voice), -5389 (fax)
Bioinformatics and Protein Engineering
1 DNA Way, MS-93                        http://www.in-machina.com/~reece/
South San Francisco, CA  94080-4990     reece@in-machina.com, GPG: 0x25EC91A0

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