Database Engine Versions and Upgrades

Accelerator supports two versions of the PostgreSQL database engine used by the VOV database, vovdb: 9.4 and 9.6. This section details the differences between these engine versions, how Accelerator determines which version to use, and how to upgrade existing databases.

Database Engine Versions

PostgreSQL 9.6 adds a new index type that reduces time to generate certain types of historical reports. Reports based on recent data, especially in a database that contains years of historical data, will see a reduction in generation time.

An existing database created with PostgreSQL 9.4 can not be used directly in 9.6; it must be upgraded. For this reason, PostgreSQL 9.4 is still supported to allow the VOV database to continue to function until an upgrade can be completed.

Determine the Current Engine Version

The existing instances of Accelerator will continue to use PostgreSQL 9.4 as the database engine for vovdb. The new instances of Accelerator will automatically use 9.6 as its database engine.

The version of PostgreSQL used by vovdb is reported in the Database Information section of the Database Configuration page. This information is only available when the database is running.

Upgrade the Database Engine

Databases for existing instances of Accelerator can be upgraded from the command line using the vovdb_util upgrade command. Example:
% vovproject enable vnc
% vovdb_util upgrade

The upgrade process requires making a copy of the existing database. While this allows for easy rollback to the original dataset and engine should errors occur, it does require that the disk on which the database is stored has free space greater than the on-disk size of the database. After the upgrade is verified, the original dataset can be deleted to restore free disk space.

The database will be offline for the duration of the upgrade. Should any errors occur, the upgraded copy of the data will be deleted, and vovdb will be restarted using the original version and data.