On Tue, Aug 03, 2010 at 03:57:27PM -0400, Tom Lane wrote: - David Kerr <d...@mr-paradox.net> writes: - > On Tue, Aug 03, 2010 at 03:49:57PM -0400, Tom Lane wrote: - > - In recent versions of PG, no. Before about 8.3 it was a Really Bad Idea, - > - because the open transaction would prevent VACUUM from reclaiming storage. - - > We're on 8.3.9, so hopefully it's fairly safe then? - - Should be. You might want to test it just to make sure I'm recalling - correctly when that got fixed. Do a BEGIN in one session, then in - another session insert and delete some rows in a table, then VACUUM - VERBOSE and see if they get cleaned up. - - regards, tom lane - Sorry for the delayed response, been in RedHat training all week.
Seems like it worked fine in 9.0beta3: SESSION 1 psql test=> begin; BEGIN test=> SESSION 2 test=# insert into test (select generate_series(1001,1999,1)); INSERT 0 999 test=# delete from test; DELETE 1999 test=# VACUUM VERBOSE test; INFO: vacuuming "public.test" INFO: "test": removed 1999 row versions in 8 pages INFO: "test": found 1999 removable, 0 nonremovable row versions in 8 out of 8 pages DETAIL: 0 dead row versions cannot be removed yet. There were 0 unused item pointers. 0 pages are entirely empty. CPU 0.00s/0.00u sec elapsed 0.00 sec. INFO: "test": truncated 8 to 0 pages DETAIL: CPU 0.00s/0.00u sec elapsed 0.00 sec. VACUUM -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
