I have a pg instance with 700GB of data, almost all of which is in one table. When I PREPARE and then COMMIT PREPARED a transaction that reads & writes to a large fraction of that data (about 10%, effectively randomly chosen rows and so every file in the table is modified), the COMMIT PREPARED sometimes takes a very long time--2 to 5 minutes. Is this expected? Is it possible for the commit to hang waiting on some lock for this long? I haven't yet been able to examine pg_locks during this 5 minute delay. There is very little concurrency--only a couple of open sessions--when the COMMIT PREPARED is issued. Thanks for your help, John -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general