Need to sniff ProgrammingError to catch some constraint violations in order to Retry

[Stuart Bishop]

In most cases, psycopg raises psycopg.IntegrityError when a constraint has been violated. We catch this exception and raise a Retry exception to get Zope3 to attempt the transaction again. This fixes a huge number of race conditions.

It seems that psycopg will also raise psycopg.ProgrammingError in some cases too, such as in OOPS-230A138 :

ProgrammingError: ERROR: duplicate key violates unique constraint "person_name_key"

[Stuart Bishop (stub)]

Turns out this is a bug in psycopg that has been fixed. We need update launchpad-dependancies to require psycopg >= 1.1.21 and update our production systems.

[Stuart Bishop (stub)]

gangotri and gandwana have been updated to psycopg-1.1.21 so this should be fixed on the production systems.