Tech Alert

12.03.2014 Tech Alert: Data Corruption Issue in PostgreSQL 9.3

A data corruption/data loss issue has been discovered in PostgreSQL 9.3. The issue can lead to updated rows being lost, or inaccessible via some types of access when the server has crashed in the past, or on replicas.

We strongly recommend upgrading to a version that fixes the issue when available. Although a fix has been committed to the postgresql community repository, no new release is available yet.
We therefore recommend using either packages prepared by the 2ndQuadrant Support Team, or to manually apply this patch (

fk_check.sql (8.1 KB)

) if your company uses self compiled binaries. For information about the 2ndQuadrant provided packages click here.

Vulnerable Versions:

  • Servers running PostgreSQL 9.3.0, 9.3.1, 9.3.2, 9.3.3

Vulnerable Installations:
  • Replicated servers using the built-in replication mechanism, including streaming replication, archive based replication and point in time recovery.
  • Servers that have been restarted with pg_ctl stop -m immediate, server crashes or by hardware crashes.

Prerequisites for corruption:
  • Several concurrent sessions performing UPDATEs
  • Foreign keys or explicit usage of SELECT ... FOR NO KEY SHARE

Data corruption symptoms include:
  • Updated rows are visible in sequential scans, but not in index scans
  • Updated versions of rows are lost

To diagnose whether you are affected we recommend rechecking all your foreign key dependencies, for example using this script (click here). Please open a support ticket if you have reasons to believe you are affected by the issue.
We have promptly informed the maintainers of the community YUM repository ([email protected]) and we will work closely with them to fix this issue.
If you require assistance with a problem caused by this issue, or you would like further advice on the workaround, please place a ticket within the Support system and we will be glad to assist. 

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