We are excited to release CitusDB 2.0 and make it available for download immediately. This version brings with it numerous new functionality and additional features. Some of the new functionality addition includes:

• Network efficient LIMIT clauses, enabled by configuration. This allows us to limit the amount of data being transferred over the network and provide better performance when using LIMIT clauses.
• Smarter task assignment policy when shard count is low. This change brings a new task-assignment policy, which enables much better cluster utilization when the shard count for a table is low compared to the number of workers.
• Smarter foreign data wrapper integration for HDFS data. We now support synchronizing Hadoop metadata to the CitusDB master node, and allow SQL queries directly on Hadoop data through foreign data wrappers. With these wrappers, users don't need to load any data into CitusDB.
• Sub-selects in the FROM clause. We now support sub-selects in the FROM clause which don't contain aggregate functions. We intend to support all FROM-clause subselects in the next few releases.

Other improvements include:

• Refreshing the worker membership list on SIGHUP, therefore removing the need to restart the master node on membership changes
• Changes to libpq to make it 100% compatible with PostgreSQL's libpq

CitusDB 2.0 is based on PostgreSQL 9.2.1, it also comes with all the great features Postgres 9.2 brings, some of which include:

• JSON data types
• Range data types
• Index-only scans

A full list of Postgres 9.2 features can be found here.

Installation notes

CitusDB 2.0 is based on PostgreSQL 9.2.1, and is binary incompatible with CitusDB 1.0. As a result, the install path for the new version has changed from /opt/citusdb/1.0 to /opt/citusdb/2.0 in order to allow for multiple versions of Citus DB to be installed in parallel.

If you are running CitusDB 1.0 and want to upgrade to v2.0, you will need to run pg_upgrade on your all nodes, and manually reload your distributed metadata. For specifics, please get in touch with us so we can assist with the upgrade process. If you are downloading and using CitusDB for the first time, please follow the installation instructions found in the CitusDB documentation page.