[OPEN-ILS-DEV] IMPORTANT: Postgres bug affecting Streaming Replication

[Mike Rylander]

UPDATE HAT TRICK:

Chris Sharp was the first to notice and mention the release of the
Postgres updates mentioned below.  Thanks, Chris!

Here's where you can download the update:
http://www.postgresql.org/about/news/1492/

Happy upgrading, folks!


On Sat, Nov 23, 2013 at 4:46 PM, Mike Rylander <mrylander at gmail.com> wrote:
> UPDATE THE SECOND:
>
> The Postgres team is planning to wrap releases to fix this issue on
> Dec 2, for release on Dec 5.  The PGDG apt repos should have the
> package at that time, and I expect the debian and ubuntu repositories
> to follow shortly thereafter.  Please mark your calendars, if you're
> affected by this bug, and plan downtime to upgrade your servers ASAP
> after the release.  For the announcement to the pgsql-hackers list
> see: http://markmail.org/thread/qnye6rk37ug52zox
>
> --miker
>
>
> On Thu, Nov 21, 2013 at 3:55 PM, Mike Rylander <mrylander at gmail.com> wrote:
>> 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 <mrylander at gmail.com> 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:  miker at esilibrary.com
>>>  | 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:  miker at esilibrary.com
>>  | 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:  miker at esilibrary.com
>  | 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:  miker at esilibrary.com
 | web:  http://www.esilibrary.com