On Fri, 21 Jul 2006 11:40:32 -0500 Erik Jones <[EMAIL PROTECTED]> wrote:
> No!!! The table is filled and entries are deleted one at a time, or in > groups, but definitely not all at once. So, then what is the > difference between scheduling regular vacuum on specific tables v. > scheduling vacuum full on specific tables? Basically, what I want to do > is to ensure that when I clean out a table row or rows at a time, the > space is immediately freed up. Why would you want to do that? PostgreSQL is not designed to operate in that fashon, and it's ineffecient. You're forcing PostgreSQL to constantly increase and decrease the amount of disk space allocated for the table, which isn't the best way to do things. Much better is to schedule frequent VACUUMs so that the table size reaches an equilibrium. This way there is always a little free space in the table so that rows can be added/updated without increasing the table size. This is how PostgreSQL is designed to run. If you don't have enough disk space to do this, then you didn't purchase large enough drives to hold your DB efficiently. You can do the VACUUM FULL as you describe, but it's non-optimal. To answer your original question directly: VACUUM FULL is expensive. It needs to lock out the table for the duration of its work, and other transactions will block during the operation. Depending on the table size, it could be prohibitively time-consuming. -- Bill Moran Potential Technologies http://www.potentialtech.com ---------------------------(end of broadcast)--------------------------- TIP 5: don't forget to increase your free space map settings
