postgresql-9.1 (9.1.6-0ubuntu11.10) oneiric-proposed; urgency=low
* New upstream bug fix release: (LP: #1055944)
- Fix persistence marking of shared buffers during WAL replay.
This mistake can result in buffers not being written out during
checkpoints, resulting in data corruption if the server later
crashes without ever having written those buffers. Corruption can
occur on any server following crash recovery, but it is
significantly more likely to occur on standby slave servers since
those perform much more WAL replay. There is a low probability of
corruption of btree and GIN indexes. There is a much higher
probability of corruption of table "visibility maps". Fortunately,
visibility maps are non-critical data in 9.1, so the worst
consequence of such corruption in 9.1 installations is transient
inefficiency of vacuuming. Table data proper cannot be corrupted by
While no index corruption due to this bug is known to have occurred
in the field, as a precautionary measure it is recommended that
production installations "REINDEX" all btree and GIN indexes at a
convenient time after upgrading to 9.1.6.
Also, if you intend to do an in-place upgrade to 9.2.X, before
doing so it is recommended to perform a "VACUUM" of all tables
while having vacuum_freeze_table_age set to zero. This will ensure
that any lingering wrong data in the visibility maps is corrected
before 9.2.X can depend on it. vacuum_cost_delay can be adjusted to
reduce the performance impact of vacuuming, while causing it to
take longer to finish.
- See HISTORY/changelog.gz for the other bug fixes.
-- Martin Pitt <email address hidden> Tue, 25 Sep 2012 07:25:37 +0200