When I restart the DB, it reports... "LOG: autovacuum launcher started".
"ps aux | grep postgres" yields this... dfg_suse> ps aux | grep postgres pgdbadm 22656 0.0 0.0 21296 2616 pts/7 S+ Dec16 0:00 /usr/intel/pkgs/postgresql/8.3.4/bin/psql -h fcadsql3.fc.intel.com hsxreuse pgdbadm 9135 0.0 0.0 50000 5924 pts/10 S 12:22 0:00 /nfs/hd/itools/em64t_linux26/pkgs/postgresql/8.3.4/bin/postgres -D /app/PG/v83 pgdbadm 9146 0.0 0.0 50000 1360 ? Ss 12:22 0:00 postgres: writer process pgdbadm 9147 0.0 0.0 50000 1156 ? Ss 12:22 0:00 postgres: wal writer process pgdbadm 9148 0.0 0.0 50000 1316 ? Ss 12:22 0:00 postgres: autovacuum launcher process pgdbadm 9149 0.0 0.0 18904 1308 ? Ss 12:22 0:00 postgres: stats collector process pgdbadm 9354 0.0 0.0 2896 760 pts/9 S+ 12:27 0:00 grep postgres TSo I assu,e it's running? This is PG v 8.3.4 on linux. -----Original Message----- From: Bill Moran [mailto:wmo...@potentialtech.com] Sent: Friday, December 17, 2010 12:17 PM To: Gauthier, Dave Cc: pgsql-general@postgresql.org Subject: Re: [GENERAL] DB files, sizes and cleanup In response to "Gauthier, Dave" <dave.gauth...@intel.com>: > Hi: > > I'm trying to justify disk space for a new linux server they're going to give > me for my Postgres instance. When I do a "du" of the place I installed the > older instance on the system that is to be replaced, I see that the vast, > vast majorityof the space goes to the contents of the "base" dir. In there > are a bunch of files with integers for names (iod's ?). And some of those > have millions of files inside. > > Is this normal? Should there be millions of files in some of these "base" > directories? > Is this indicative of some sort of problem or lack of cleanup that I should > have been doing? > > The "du" shows that I'm using 196G (again, mostly in "base") but > pg_database_size shows something like 1/4 that amount, around 50G. I'd like > to know if there's something I'm supposed to be doing to cleanup old > (possibly deleted) data. > > Also, I was running pg_size_pretty(pg_database_size('mydb')) on all the dbs. > It runs very fast for most, but just hangs for two of the databases. Is this > indicative of some sort of problem? (BTW, the 2 it hangs on are very much > like others that it doesn't hang on, so I used those numbers to estimate the > 50G) 1) Do you have autovacuum running, or do you have a regular vacuum scheduled? Because this seems indicative of no vacuuming, or errors in vacuuming, or significantly insufficient vacuuming. 2) Unless your databases contain close to 100G of actual data, that size seems unreasonable. 3) pg_database_size() is probably not "hanging", it's probably just taking a very long time to stat() millions of files. Overall, I'm guessing you're not vacuuming your databases on a proper schedule and that most of that 196G is bloat that doesn't need to be there. When bloat gets really bad, you're generally better off dumping the datbases and restoring them, as a vacuum full might take a very, very long time. If you can demonstrate that the cause of this is table bloat, then I would go through all your databases and do a vacuum full/reindex or do a dump/restore if the problem is very bad. Once you have done that, your du output should be more realistic and more helpful. Then, take some time to set up appropriate autovacuum settings so the problem doesn't come back. -- Bill Moran http://www.potentialtech.com http://people.collaborativefusion.com/~wmoran/
