According to http://www.postgresql.org/docs/8.3/static/kernel-resources.html The maximum shared memory usage of a connection in bytes is 1800 + 270 * max_locks_per_transaction max_locks_per_transaction default is 64 19080 Bytes or .018 mb's per connection or 1.819 mb at 100 default connections With a Gig of Phsical Ram setting Shared Buffers to use 25% - 256 mb dedicated to Postgres default is using roughly 0.75% for connections You can extrapolate this out taking into consideration all your specific variables, total physical RAM, postgresql.conf settings etc but I wouldn;t run off to use pgpool unless your in an extremly connection heavy environment as it does add an additional layer within the client server connection and is another component to config and admin. -- View this message in context: http://postgresql.1045698.n5.nabble.com/max-connections-tp5722890p5722899.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general