[PERFORM] Queries within a function

[Mridula Mahadevan]

Hi,
 I am running a bunch of queries within a function, creating some temp tables 
and populating them. When the data exceeds say, 100k the queries start getting 
really slow and timeout (30 min). when these are run outside of a 
transaction(in auto commit mode), they run in a few seconds. Any ideas on what 
may be going on and any postgresql.conf parameters etc that might help?
Thanks