On Mon, May 15, 2006 at 03:04:47PM -0400, Tom Lane wrote: > Martijn van Oosterhout <kleptog@xxxxxxxxx> writes: > > Vacuum will make anything that disappeared by wraparound in the last > > billion transactions reappear, so a databasewide vacuum should solve > > all your problems, no need to dump... > > Oh, I had forgotten about that. Did we establish that 7.4.* works that > way? I think so, but obviously I've been programming too many hours in > a row :-( Well, I demonstrated it for 8.1beta here: http://archives.postgresql.org/pgsql-general/2005-11/msg00097.php And I just demonstrated it on a test 7.4.7 database here (Debian 7.4.7-6 to be precise). test=# select ctid, xmin, xmax, cmin, cmax, * from test; ctid | xmin | xmax | cmin | cmax | x -------+------------+------+------+------+--- (0,1) | 541 | 0 | 0 | 0 | 1 (0,2) | 2147484153 | 0 | 0 | 0 | 2 (0,3) | 2147484183 | 0 | 0 | 0 | 3 (3 rows) ### Row is still there... test=# select ctid, xmin, xmax, cmin, cmax, * from test; ctid | xmin | xmax | cmin | cmax | x -------+------------+------+------+------+--- (0,2) | 2147484153 | 0 | 0 | 0 | 2 (0,3) | 2147484183 | 0 | 0 | 0 | 3 (2 rows) ### OMG, row is gone test=# vacuum test; VACUUM test=# select ctid, xmin, xmax, cmin, cmax, * from test; ctid | xmin | xmax | cmin | cmax | x -------+------------+------+------+------+--- (0,1) | 2 | 0 | 0 | 0 | 1 (0,2) | 2147484153 | 0 | 0 | 0 | 2 (0,3) | 2147484183 | 0 | 0 | 0 | 3 (3 rows) ### Yay row is back test=# select version(); version ------------------------------------------------------------------------------------------------------- PostgreSQL 7.4.7 on i386-pc-linux-gnu, compiled by GCC i386-linux-gcc (GCC) 3.3.5 (Debian 1:3.3.5-12) (1 row) Have a ncie day, -- Martijn van Oosterhout <kleptog@xxxxxxxxx> http://svana.org/kleptog/ > From each according to his ability. To each according to his ability to litigate.
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