Sorry for top-posting -- challenged reader.
Can't speak directly to PostgreSQL but in Informix the fill factor is useful for tweaking indexes. A very high fill factor is useful for tables that are static -- any inserts or changes to the index trigger a *lot* of moving of b-tree branches. But the high fill factor means that each page has more useful data references in it. A very low fill factor means that pages are "sparse" and so inserts and updates are less likely to trigger massive b-tree rebalancings.
I've never used it on PostgreSQL (yet!) but am looking forward to it.
Beware of premature optimization!
HTH,
Greg Williamson
Senior DBA
GlobeXplorer LLC, a DigitalGlobe company
Confidentiality Notice: This e-mail message, including any attachments, is for the sole use of the intended recipient(s) and may contain confidential and privileged information and must be protected in accordance with those provisions. Any unauthorized review, use, disclosure or distribution is prohibited. If you are not the intended recipient, please contact the sender by reply e-mail and destroy all copies of the original message.
(My corporate masters made me say this.)
-----Original Message-----
From: pgsql-general-owner@xxxxxxxxxxxxxx on behalf of Richard Broersma Jr
Sent: Tue 9/18/2007 10:29 AM
To: Phoenix Kiula; Bill Moran
Cc: pgsql-general@xxxxxxxxxxxxxx
Subject: Re: For index bloat: VACUUM ANALYZE vs REINDEX/CLUSTER
--- Phoenix Kiula <phoenix.kiula@xxxxxxxxx> wrote:
> What constitutes a "small fill factor"? Would 70 be good? I guess my
> current must have been the default, which the manual says is 100.
On the following link:
http://www.postgresql.org/docs/8.2/interactive/sql-createindex.html#SQL-CREATEINDEX-STORAGE-PARAMETERS
I found this:
"B-trees use a default fillfactor of 90, but any value from 10 to 100 can be selected."
Regards,
Richard Broersma Jr.
---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
