Carrying Case Owner's Manual

94 Oracle TimesTen In-Memory Database Installation Guide
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
-inline command
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