PostgreSQL 9.0's first release candidate arrives
The first release candidate for version 9.0 of the PostgreSQL open source database has been released after four months in beta. The developers expect no changes in commands, interfaces or APIs between the release candidate and the final release, though there may be more release candidates before then, depending on bug reports. The most prominent feature in the new release is integrated replication using "Hot Standby" and "Streaming Replication" while other features include full support for 64-bit Windows, improved reporting queries, SQL standard per-column triggers, enhanced Perl and Python integrations and easier database permission management.
Streaming Replication allows a slave system to connect to the primary server and receive a stream of WAL (Write Ahead Log) records as they are generated, rather than having to wait for those records to be written to disk and picked up later. This allows the standby to be more up to date. Hot Standby allows connection to a server which is in recovery mode. While still in recovery mode the server can process read-only queries and can move to normal operations without disconnection users.
The on disk format has changed from previous versions so a move to PostgreSQL 9.0 release candidate from a previous version requires a
pg_dump to export from the older database into the new version. As an alternative, the data directory can be updated directly using
pg_migrator. As with all pre-release software which has been made available for testing, use in production environments is not recommended.
Full details of the improvements in 9.0 are available in the release notes. The source for the new release candidate is available to download as are executable binaries and installers for 32-bit and 64-bit Linux and Windows and Mac OS X. Instructions on how to test and report bugs are also available.
PostgreSQL is an open-source Object-Relational DBMS supporting almost all SQL constructs. The PostgreSQL development includes employees of Red Hat, F-Secure and EnterpriseDB. PostgreSQL is released under the PostgreSQL License, a liberal Open Source license, similar to the BSD or MIT licenses.