On 28th of June, Simon Riggs committed patch: ALTER TABLE ... ALTER CONSTRAINT for FKs Allow constraint attributes to be altered, so the default setting of NOT DEFERRABLE can be altered to DEFERRABLE and back. Review by Abhijit Menon-Sen

On 20th of November Tom Lane committed patch by Takahiro Itagaki which adds interesting functionality: Add a WHEN clause to CREATE TRIGGER, allowing a boolean expression to be checked to determine whether the trigger should be fired.   For BEFORE triggers this is mostly ...

On 29th of July ( I know, there is a long backlog in waiting for 8.5 series. I'm working on it :), Tom Lane committed patch by Dean Rasheed: Support deferrable uniqueness constraints.   The current implementation fires an AFTER ROW trigger for ...