Re: Transparent Session Migration?

From: Jeremy Schneider <>
Date: Mon, 25 May 2009 22:53:10 -0500
Message-ID: <>

Yong Huang wrote:
>> has anyone ever seen any information about Transparent Session Migration?
> This is the first time I heard of this concept (other than seeing TSMSYS 
> user before). 

That really is interesting. I found a few references in an old white paper and the 10.1 New Features manual with a disclaimer that it was supposed to come in a future version (10.2 according to Mike Ault) - but I don't think it was ever released. Looks like it was tied to another feature called "Resonance". But who knows - might or might not still be coming in a future release, under the same or a different name.

Oracle Database 10g: The Database for the Grid, An Oracle White Paper November 2003
Resonance: A cluster is a user-defined set of servers that are clustered together using Oracle Portable Clusterware. You run many databases on the same cluster and define your service policies for these databases. Resonance will dynamically grow and shrink the number of servers your individual databases are running on in this cluster to meet your service-level objectives. This is done automatically without requiring any user intervention. Imagine you have a large cluster with many databases in it. If you had to manage it manually, you would have to constantly monitor the load on each of those databases and then you would have to manually shut down or bring up Oracle Database 10g: The Database for the Grid Page 10 additional instances of those databases. Your shut down command might take a very long time, as there might be active sessions on the database instance. Oracle Database 10g does this for you. It constantly monitors the load for you. When it needs to shut down an instance, it automatically migrates active sessions to other active instances of the database. Similarly, when it brings up an additional instance of a database, it automatically balances the workload across all the instances of this database.

==> Oracle Database Resonance: Resources are dynamically expanded when needed and are shrunk when not needed or when priority tasks need them. Database Resonance is the provisioning utility for the Oracle RAC. Through the database resonance utility, it becomes possible for the administrators to define and configure policy-based CPU provisioning (in terms of nodes) and capacity on demand with automatic load balancing.

DBA(s) can define the services-level policies based on CPU utilization or service response times and also set up priority of each database. Oracle automatically starts and stops the additional instances to meet service-level policies.

We understand this module or utility will be available in 10.2 g database release.

==> Resonance: Reduces costs of operating databases by improving resource utilization and eliminating the need for manually monitoring and allocating resources. Automatically re-provisions resources to meet changing business needs.

Transparent Session Migration: Automatically migrates sessions, including all state, from one instance to another, with no impact on end-users. Rebalances sessions across instances for load balancing, and in preparation for deprovisioning an instance.

Grid Features: Oracle Database New Features for Oracle Database 10g Release 1 ( lists two Grid features that are not available in the first release of Oracle Database 10g; Resonance and Transparent Session Migration. These features will be available in a future release.


Jeremy Schneider
Chicago, IL

Received on Mon May 25 2009 - 22:53:10 CDT

Original text of this message