In response to Ben <bench@xxxxxxxxxxxxxxx>: > Hey Bill. How do you monitor your shared buffer usage? My understanding > was that there wasn't a good way to see what was used vs. allocated. echo "select count(*) from pg_buffercache where reldatabase is not null;" | $PSQL_BIN -P tuples_only -U pgsql postgres | head -1 Of course, you have to install the pg_buffercache contrib module first. > On Wed, 17 Jan 2007, Bill Moran wrote: > > > > > We just did a bunch of maintenance on one of our production databases that > > involved a lot of alter tables and moving records about and the like. > > > > Afterwards, I did a vacuum full and analyze to get the database back on > > track -- autovac maintains it under normal operations. > > > > Today I decided to run reindex during a slow period, and was shocked to > > find the database size drop from 165M to 30M. Keep in mind that the > > 165M is after vacuum full. So, apparently, there was 135M of index bloat? > > That seems a little excessive to me, especially when the docs claim that > > reindexing is usually not necessary. > > > > This is PostgreSQL 8.1.4. We've got upgrades to 8.2 planned, but it's > > going to be a few months before we can squeak that into a maintenance > > window. Additionally, I thought all the big index improvements were > > added in 7.4. > > > > I guess my question is whether or not this is expected. It's obviously > > not a good thing -- I've noticed that shared buffer usage has dropped > > dramatically as well (from 28,000 to 7000). I hadn't expected index > > bloat of this magnitude, and I'm concerned about when the database hits > > 2 or 3 G in size and has 12G just in indexes that take hours to rebuild. > > > > -- > > Bill Moran > > Collaborative Fusion Inc. > > > > ---------------------------(end of broadcast)--------------------------- > > TIP 6: explain analyze is your friend > > > > > > > > -- Bill Moran Collaborative Fusion Inc. wmoran@xxxxxxxxxxxxxxxxxxxxxxx Phone: 412-422-3463x4023 **************************************************************** IMPORTANT: This message contains confidential information and is intended only for the individual named. If the reader of this message is not an intended recipient (or the individual responsible for the delivery of this message to an intended recipient), please be advised that any re-use, dissemination, distribution or copying of this message is prohibited. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message, which arise as a result of e-mail transmission. ****************************************************************
