Oracle Audio Technologies B31679-01 manual Online upgrades with replication

Online upgrades with replication

When upgrading to a new major release of TimesTen, you may have a mission critical data store that needs to remain continuously available to your applications. You can use TimesTen replication to keep two copies of a data store synchronized, even when the data stores are from different versions of TimesTen, allowing your applications to stay connected to one copy of the data store while the other one is being upgraded. When the upgrade is finished, any updates that have been made on the active data store will be transmitted immediately to the upgraded data store, and your applications can then be switched to the upgraded data store with no data loss and no down time. For more information, see “Performing an online upgrade with replication” on page 104.

The online upgrade process only supports updates to user tables during the upgrade. Data definition changes such as CREATE TABLE or CREATE INDEX are not replicated. In addition, all tables to be replicated must have a PRIMARY KEY or a unique index on non- nullable columns. Also, because two copies of the data store to be upgraded are required, you must have twice the memory and disk space that the data store usually requires available, if performing the upgrade on a single system.

Note: Replication is not supported between 32-bit and 64-bit data stores. Also, tables migrated using the ttMigrate -inlinecommand should not be replicated with tables where the option is not supported, as inline columns cannot be replicated with not inline columns.

Online upgrades with Client/Server

If you are upgrading a TimesTen Client/Server installation to a new major release, you can minimize downtime by performing a client/ server online upgrade. During this process, TimesTen clients from the previous version are able to continue to communicate with a data store that has been upgraded to the new version. There are two ways to do this:

•If you are upgrading from a version of TimesTen before 6.0, you can choose to leave the old version of TimesTen Server installed when you install the new version. The old version of TimesTen Server may then be configured to pass connection requests from the old version of TimesTen Client to the new version of TimesTen Server once the data store has been upgraded. For more information, see “Performing

94Oracle TimesTen In-Memory Database Installation Guide