access during the VACUUM. A new VACUUM FULL command does old-style

vacuum by locking the table and shrinking the on-disk copy of the table.

Transactions - There is no longer a problem with installations

that exceed four billion transactions.

OID's - OID's are now optional. Users can now create tables

without OID's for cases where OID usage is excessive.

Optimizer - The system now computes histogram column statistics

during ANALYZE, allowing much better optimizer choices.

Security - A new MD5 encryption option allows much more secure

storage and transfer of passwords. A new unix-domain socket

authentication option is available on Linux and *BSD systems.