Viktor wrote: > We are currently running PostgreSQL version 9.1.9-1~bpo60+1 (Debian Squeeze) and would like to update > it to 9.1 9.1.12-0wheezy1. > > But there is one serious issue about this update: > > " > E.3.2. Changes > > > > > Fix VACUUM's tests to see whether it can update relfrozenxid (Andres Freund) > > In some cases VACUUM (either manual or autovacuum) could incorrectly advance a table's relfrozenxid > value, allowing tuples to escape freezing, causing those rows to become invisible once 2^31 > transactions have elapsed. The probability of data loss is fairly low since multiple incorrect > advancements would need to happen before actual loss occurs, but it's not zero. Users upgrading from > releases 9.0.4 or 8.4.8 or earlier are not affected, but all later versions contain the bug. > > The issue can be ameliorated by, after upgrading, vacuuming all tables in all databases while having > vacuum_freeze_table_age <http://www.postgresql.org/docs/9.1/static/runtime-config-client.html#GUC- > VACUUM-FREEZE-TABLE-AGE> set to zero. This will fix any latent corruption but will not be able to fix > all pre-existing data errors. However, an installation can be presumed safe after performing this > vacuuming if it has executed fewer than 2^31 update transactions in its lifetime (check this with > SELECT txid_current() < 2^31). > > " > > Please explain should I run VACUUM on all tables after the update if > > > postgres=# SELECT txid_current() < 2^31; > ?column? > ---------- > t > (1 row) Yes. That's what the release notes say. One easy option is to run PGOPTIONS='-o vacuum_freeze_table_age=0' vacuumdb Yours, Laurenz Albe -- Sent via pgsql-admin mailing list (pgsql-admin@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-admin
