Sequence Manager: failed to obtain next ID block due to thread contention

Hi I am experiencing a number of warnings/errors related to the sequence manager

2012.06.01 02:24:42 org.jivesoftware.database.SequenceManager - WARNING: failed to obtain next ID block due to thread contention. Trying again…

2012.06.01 02:29:00 org.jivesoftware.database.SequenceManager - WARNING: failed to obtain next ID block due to thread contention. Trying again…

2012.06.01 02:33:01 org.jivesoftware.database.SequenceManager - WARNING: failed to obtain next ID block due to thread contention. Trying again…

2012.06.01 03:21:12 org.jivesoftware.database.SequenceManager - WARNING: failed to obtain next ID block due to thread contention. Trying again…

2012.06.01 04:55:10 org.jivesoftware.database.SequenceManager - WARNING: failed to obtain next ID block due to thread contention. Trying again…

2012.06.01 04:55:22 org.jivesoftware.database.SequenceManager - WARNING: failed to obtain next ID block due to thread contention. Trying again…

after this set of errors

I get

com.mysql.jdbc.exceptions.MySQLIntegrityConstraintViolationException: Duplicate entry ‘1492’ for key ‘PRIMARY’

I’m not sure what causes this. Can anyone enlighten me?

Best Regards,

Stevenson Lee