UPDATE I need clarify and correct the information below: this is not restricted streaming-replication based hot-standby replicas, it is for all hot_standby-enabled replicas (regardless of the mechanism used to ship the WAL data) when there is a recovery.conf in place. This is per: http://markmail.org/message/p6bcdo5h2ll4kk3k
On Thu, Nov 21, 2013 at 1:35 PM, Mike Rylander <[email protected]> wrote: > THE BAD NEWS: > > If your site uses Postgres' streaming replication to create a > read-only hot-standby, such as for reporting or to support search > capacity needs, this message is for you. > > On Nov, 18, a bug was reported to the Postgres hackers list that can > cause extreme corruption of hot-standby secondary servers. Known > affected versions include 9.2.5 and 9.3.1. It is likely that this > goes as far back as 9.1. > > The nature of the bug is such that it is somewhat hard to provoke. > However, it can occur at any standby startup if the secondary is in > hot-standby mode, and not only during the initial secondary creation. > In other words, every restart of a hot-standby secondary instance of > Postgres is another chance to run afoul of this bug. It is most > likely to occur under high write load or situations where there is > significant lag during standby startup. > > Symptoms include: missing data; apparently-duplicated data; mismatch > between index and heap data; "impossible" constraint violations > (unique and fkey). > > The underlying cause of these symptoms is a loss of proper transaction > visibility information on the hot-standby secondary. > > THE GOOD NEWS: > > There is an apparent fix being tested now by several large Postgres > entities. It is expected that a point release for all affected > versions will be made available ASAP. Additionally, if you have > already been bitten by the corruption bug, there is a straight-forward > procedure for recover, which I am sure will be detailed in the release > notes for the upcoming point releases. > > You can read the full thread from the pgsql-hackers mailing list here: > http://markmail.org/message/p54pqkykjtwvog3h > > -- > Mike Rylander > | Director of Research and Development > | Equinox Software, Inc. / Your Library's Guide to Open Source > | phone: 1-877-OPEN-ILS (673-6457) > | email: [email protected] > | web: http://www.esilibrary.com -- Mike Rylander | Director of Research and Development | Equinox Software, Inc. / Your Library's Guide to Open Source | phone: 1-877-OPEN-ILS (673-6457) | email: [email protected] | web: http://www.esilibrary.com
