BUG #13628: System Hangs During Update Query

The following bug has been logged on the website:

Bug reference:      13628
Logged by:          manoj kumar
Email address:      manoj.sagar@globallogic.com
PostgreSQL version: 9.1.3
Operating system:   OpenSuse
Description:

Hi I am running an update command on the postgress ,the query is quite long
so sometimes my system hangs up during this command and we have to restart
the postgres as a workaround .WE are not able to locate the problem so
please help us in this scenario,we have checked the pg_stats_activity and
pg_locks also but no information could be fetched about the issue