On May 7, 2007, at 9:44 AM, Pavel Stehule wrote:
Hello,
I would need more info about index types in postgre (btree, hash, gin and gist) - is there any guide that explains in detail when to use which index type? These index types have different performance with certain collumn types and data characteristics store in them. There's not much info about it pg docs. So, does any document describing detailed index usage or do you
have any personal recomendations when to use which index?

http://people.planetpostgresql.org/mha/index.php?/archives/112-GIN- performance-postgresql.org-websearch-part-2.html http://people.planetpostgresql.org/xzilla/index.php?/archives/278- PostgreSQL-full-text-search-testing.html


Summary:
* fulltext, GIS, arrays .. gin, gist indexes (gin is faster, but slow update)
* others .. btree index (I don't know anybody who use hash index)

GiST can also be useful if you have to query in multiple dimensions, which can occur outside the normal case of geometry. Best example I know of is a table containing duration information in the form of start_time and end_time. Trying to query for what events happened on 5/28/2005 will generally be much cheaper with a GiST index than a b- tree.
--
Jim Nasby                                            [EMAIL PROTECTED]
EnterpriseDB      http://enterprisedb.com      512.569.9461 (cell)



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