Upgrading an Installation With pg_upgrade v11

While minor upgrades between versions are fairly simple and require only the installation of new executables, past major version upgrades has been both expensive and time consuming. pg_upgrade facilitates migration between any version of Advanced Server (version 9.0 or later), and any subsequent release of Advanced Server that is supported on the same platform.

Without pg_upgrade, to migrate from an earlier version of Advanced Server to Advanced Server 11, you must export all of your data using pg_dump, install the new release, run initdb to create a new cluster, and then import your old data.

pg_upgrade can reduce both the amount of time required and the disk space required for many major-version upgrades.

The pg_upgrade utility performs an in-place transfer of existing data between Advanced Server and any subsequent version.

Several factors determine if an in-place upgrade is practical:

• The on-disk representation of user-defined tables must not change between the original version and the upgraded version.
• The on-disk representation of data types must not change between the original version and the upgraded version.
• To upgrade between major versions of Advanced Server with pg_upgrade, both versions must share a common binary representation for each data type. Therefore, you cannot use pg_upgrade to migrate from a 32-bit to a 64-bit Linux platform.

Before performing a version upgrade, pg_upgrade will verify that the two clusters (the old cluster and the new cluster) are compatible.

If the upgrade involves a change in the on-disk representation of database objects or data, or involves a change in the binary representation of data types, pg_upgrade will be unable to perform the upgrade; to upgrade, you will have to pg_dump the old data and then import that data into the new cluster.

The pg_upgrade executable is distributed with Advanced Server 11, and is installed as part of the Database Server component; no additional installation or configuration steps are required.