On Mon, 2003-01-06 at 16:49, Gerard Samuel wrote: > > > >Surely we'd need to know how many _rows_ there are in those tables? Also > >how many indexes and index rows? > > > True. But not sure how to gather all that info for right now. > To get a more accurate picture, I dropped the one database that is in > Postgre, stopped and restarted Postgre. > It seems to be using just over 62M. > I recreated the database and file usage remains unchanged (looking via > df -H), the database isn't really that large maybe about 1000 rows of > data currently. That seems normal. I think that PostgreSQL default WAL setup is to have four write-ahead log files of 16MB each, which would be 64M, and your data would kind of pale into insignificance beside that. The WAL files are where PostgreSQL writes changes during a database transaction before the transaction is committed to the database. Or something like that... (someone who really understands the database internals is probably cringing at my description :-) This overhead is kind of one-off. On systems that do very large transactions before COMMIT you will find the numbers of these files will increase, but in general 4 x 16M will be enough for most things. On a much larger database than the one on my laptop, the WAL files take up 130M even though the DB itself takes up 2.5G. The WAL files are in the data/pg_xlog directory, separate to the data/base directory for the actual database files, at least that's how it's organised under Debian - I think it's the same under other setups but YMMV. > > > >I believe that PostgreSQL does have greater overhead on disk than MySQL, > >however. Just to have the database started will mean that you have a > >number of write-ahead logs (typically 16MB each - on my laptop these > >take up 114M) which are used internally by the database server for > >transaction handling - MySQL doesn't need these, of course. > > > Well if its normal for PostgreSQL to need more disk space, looks like Im > going to have to do a couple of disk to disk copying soon, > and repartion my HD. Hopefully not too dramatic. I've given up on multiple partitions for my laptop the last few years, currently: 100M /boot, 512M of tmpfs on /tmp and the remaining 59G on / and I have saved myself a lot of hassles. Cheers, Andrew. -- --------------------------------------------------------------------- Andrew @ Catalyst .Net.NZ Ltd, PO Box 11-053, Manners St, Wellington WEB: http://catalyst.net.nz/ PHYS: Level 2, 150-154 Willis St DDI: +64(4)916-7201 MOB: +64(21)635-694 OFFICE: +64(4)499-2267 Survey for nothing with http://survey.net.nz/ ---------------------------------------------------------------------
