[seanc@FreeBSD.org: Re: cvs commit: ports/databases/postgresql-devel Makefile distinfo pkg-message pkg-plist]

Sean Chittenden seanc at FreeBSD.org
Wed Oct 1 00:46:27 PDT 2003

FWIW, I just updated postgresql-devel to the latest snapshot and as
promised, I added the _ability_ to change postgresql-devel's block
sizes to 16K or 32K.  The default block size still remains at 8K.

If you have hardware and testing time to burn, I'd be interested in
anyone's results if someone decides to perform any kind of
benchmarking with differing block sizes.  Some have found the bigger
block sizes to speed up some types of work loads anywhere from 10-25%,
others have found no difference.  Any data that people have on this
would be of interest to me and I would greatly appreciate hearing
about anyones results.  Info that's helpful include what version
FreeBSD, file system info, UFS block sizes as well as PG block sizes,
and basic info about your app that you used to test (50/50 read
writes, 40/60, etc).

Please note that changing block sizes should be done with care and
will result in the need to dump/initdb/reload, and adjustment of
postgresql.conf values (ex: effective_cache_size) that depend on 8K
block sizes.  Playing with PG's block sizes will create
incompatibilities between databases/postgresql-devel and
databases/postgresql7 if the block sizes differ.  You have been

If you have any questions about this, please take up such discussions
on the database@ list.  -sc

PS  Valid values for WITH_PGBLOCKSIZE are "16K" or "32K"

Sean Chittenden
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