On Thu, 31 Jul 2003, Andrew Sullivan wrote: > On Thu, Jul 31, 2003 at 08:51:09AM -0400, [EMAIL PROTECTED] wrote: > > > > well, i can admit that i am confused. my assumption is that when a row > > is deleted in pg, that row is merely marked as 'gone' until a vacuum-full > > is done. my further assumption is that if i continue to add rows, those > > rows are not necessarily appended to the end of the physical data file, > > but can be written over 'deleted' rows. > > Your assumption is wrong. VACUUM without FULL will allow you to > write over the free space now available in your data files, subject > to the limitations of tracking as determined by your FSM settings. > > VACUUM FULL actually shortens the data file. Except for cases having > to do with large tuples that won't fit in the previous page, VACUUM > FULL means that you can't fit any more data in that file, once the > VACUUM FULL is done. > > A > >
well, i was close. i didn't realize that i had to do a (non-full) vacuum to mark deleted space as free. but after that, i am still left with a potentially sparse file and i don't really have a way to guess how much free space is available until i do a full vacuum, correct? (at which time the file size(s) will indicate the amount being used) just started looking at fsm. thanks for the pointer there. i hope i'm not acting too obtuse here. thanks. pg ---------------------------(end of broadcast)--------------------------- TIP 4: Don't 'kill -9' the postmaster
