++ New Features Summary BDB 4.2 -> BDB 4.5
==========================================

- multi-version concurreny control - imporves performance of highly concurrent, 
  mixed read/write systems by giving each user their own “snapshot” of the 
  database and managing concurrent changes by many users
- online upgrade
- utility for performing hot backups
- major improvements to the replication feature
  - choice of using replication manager with default TPC/IP setup or 
    lower level configuration API
  - support for delayed client synchronzation
  - support for client-to-client sync
  - support for bulk transfer


++ Overview of new features from Oracle's change log
====================================================

The "change log" for BDB 4.5 says (
http://www.oracle.com/technology/products/berkeley-db/db/update/4.5.20/if.4.5.20.html ):

New Features:
A new event style notification.
Multi-Version Concurrency Control for the Btree/Recno access methods.
A new replication framework with a default TCP/IP setup.
A new port to the BREW platform (a cell phone OS), not fully supported but ready for testing.
Several enhancements to the Java Collections API including the implementation
of the size() method.
Online replication upgrades for high availability replicated 24/7 systems.


The "change log" for BDB 4.4 says (
http://www.oracle.com/technology/products/berkeley-db/db/update/4.4.20/if.4.4.20.html ):

New Features:
Add support to compact an existing Btree database. [#6750]
Add support for named in-memory databases. [#9927]
Add support for database environment recovery serialization. This simplifies
multi-process application architectures. Add DB_REGISTER flag to DB_ENV->open(). [#11511]
Add utility for performing hot backups of a database environment. [#11536]
Add replication configuration API. [#12110]
Add replication support to return error instead of waiting for client sync to complete. [#12110]
Add replication support for delayed client synchronization. [#12110]
Add replication support for client-to-client synchronization. [#12110]
Add replication support for bulk transfer. [#12110]
Add new flags DB_DSYNC_DB and DB_DSYNC_LOG [12941]
Add DbEnv.log_printf, a new DbEnv method which logs printf style formatted
strings into the Berkeley DB database environment log. [#13241]


The "change log" for BDB 4.3 says (
http://www.oracle.com/technology/products/berkeley-db/db/update/4.3.29/if.4.3.29.html ):

New Features:
Add support for light weight, transactionally protected Sequence Number generation. [#5739]
Add support for Degree 2 isolation. [#8689]
Add election generation information to replication to support Paxos compliance. [#9068]
Add support for 64-bit and ANSI C implementations of the RPCGEN utility. [#9548]