Release Date: 2015-06-12
This release contains a small number of fixes from 9.0.21. For information about new features in the 9.0 major release, see Section E.24.
The PostgreSQL community will stop releasing updates for the 9.0.X release series in September 2015. Users are encouraged to update to a newer release branch soon.
A dump/restore is not required for those running 9.0.X.
However, if you are upgrading from a version earlier than 9.0.18, see Section E.6.
Fix rare failure to invalidate relation cache init file (Tom Lane)
With just the wrong timing of concurrent activity, a VACUUM FULL on a system catalog might fail to update the "init file" that's used to avoid cache-loading work for new sessions. This would result in later sessions being unable to access that catalog at all. This is a very ancient bug, but it's so hard to trigger that no reproducible case had been seen until recently.
Avoid deadlock between incoming sessions and CREATE/DROP DATABASE (Tom Lane)
A new session starting in a database that is the target of a DROP DATABASE command, or is the template for a CREATE DATABASE command, could cause the command to wait for five seconds and then fail, even if the new session would have exited before that.