On Thu, Jan 22, 2009 at 02:52:12PM -0500, Harold A. Gim?nez Ch. wrote: > Hi list, > > Clustering my indexes dramatically improves the query performance of many of > my queries. Also, the actual clustering takes a very long time for big > databases, roughly 20 hours. I have two questions about how to improve this: > > 1. I've tweaked maintenance_mem_max and effective_cache_size to a point > where the cluster operation uses a good chunk of my physical RAM, and the OS > does not start swapping. Is there any other parameter I should look at? > > 2. Reading the documentation for cluster at > http://www.postgresql.org/docs/8.3/interactive/sql-cluster.html, I see that > all clustering does is reorder the data on disk to 'match' the order of the > clustered index. My question is, if I dump a clustered database using > pg_dump in custom format, is it necessary to cluster after restoring it? Or > does a dump/restore not guarantee that the order of the data restored is the > same as the original dumped database? > > 3. Somewhat related to #2, what is the best way to move data from a staging > database on one server, to the production environment on a different server? > I've been using pg_dump/pg_restore, but there must be a better way... > > > Thanks for any pointers, > > -Harold Harold, There have been discussions on the hackers list about the pessimal cluster performance. Here is a pointer to the discussion, it seems that a faster way is to build a new table with the desired orderwith "CREATE TABLE AS ... ORDER BY ...": http://www.mail-archive.com/pgsql-hackers@xxxxxxxxxxxxxx/msg121205.html Cheers, Ken -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
