| From: | Bryce Nesbitt <bryce2(at)obviously(dot)com> |
|---|---|
| To: | pgsql-sql(at)postgresql(dot)org |
| Subject: | Measuring degredation of CLUSTER INDEX operation |
| Date: | 2008-11-10 19:54:46 |
| Message-ID: | 49189186.4070805@obviously.com |
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| Lists: | pgsql-sql |
I've got a table for which "CLUSTER tablename USING index" makes an
order of magnitude difference.
Are there ways to determine how "unclustered" this table becomes over
time, so I can schedule downtime to recluster? I could use the pg_stat
tables, but this seems awkward.
-Bryce
NB: For manual optimization work, it would be handy to have a feature in
"ANALYZE VERBOSE" which gives a measure from 0-100%, right next to the
"rows examined". 100% would be an optimally clustered result. 0% would
be every row came from a distinct block on disc.
Related links:
http://www.postgresql.org/docs/8.3/static/sql-cluster.html
http://www.postgresonline.com/journal/index.php?/archives/10-How-does-CLUSTER-ON-improve-index-performance.html
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