Oracle RAC - Load Balancing Problem

Question

Our J2EE application transactions (Container-managed) are using MULTIPLE database connections to complete one business transaction.
Recently we swiched to below Oracle RAC configuration, and it is creating problems.
BEA 8.1 SP5 Multi Pools
Oracle 9i RAC (2 instances) : Active - Active
Algorithm : Load Balancing
Driver (JDBC) : Oracle 10g Release 1 Thin Driver
non-XA transactions
Looks like when LB algorithm is chosen, the load balacing is only **connection-aware** and NOT **transaction-aware**. Because of this, the application gets one connection from one RAC instance, and other from other instance is creating problems.
Is there any work-around exist for this problem?
If we chose, HIGH_AVAILABILTY algorithm, everything is fine. But we would like to make use of both instances.

Answer 1

Srinivas Chintala wrote:
Hello Joe,
Here is the configuration:
<JDBCConnectionPool DriverName="oracle.jdbc.OracleDriver"
InitialCapacity="10" MaxCapacity="30" Name="rac_node1"
PasswordEncrypted="{3DES}5M6WvgV8GsA=" Properties="user=apps"
StatementCacheSize="20" Targets="app_cluster"
TestConnectionsOnCreate="true" TestConnectionsOnRelease="true"
TestConnectionsOnReserve="true"
TestTableName="SQL SELECT 1 FROM DUAL" URL="jdbc:oracle:thin:@usplgmnvmdb001.iweb.com:1521:prod_1"/>
<JDBCConnectionPool DriverName="oracle.jdbc.OracleDriver"
InitialCapacity="10" MaxCapacity="30" Name="rac_node2"
PasswordEncrypted="{3DES}5M6WvgV8GsA=" Properties="user=apps"
StatementCacheSize="20" Targets="app_cluster"
     TestConnectionsOnCreate="true" TestConnectionsOnRelease="true"
TestConnectionsOnReserve="true"
TestTableName="SQL SELECT 1 FROM DUAL" URL="jdbc:oracle:thin:@usplgmnvmdb002.iweb.com:1521:prod_2"/>
<JDBCMultiPool AlgorithmType="Load-Balancing" Name="appmutlipool"
PoolList="rac_node1,rac_node2" Targets="app_cluster"/>
<JDBCDataSource JNDIName="appdatasource" Name="AppDatasource"
PoolName="appmutlipool" Targets="app_cluster"/>
ChintalaHi, OK, that looks fine, except:
1 - I would define the initial and max capacity = 30, for performance and stability.
2 - For more performance, turn off test-on-release. It's a waste of cycles.
3 - You can change your TestTableName to "SQL BEGIN NULL; END;" which goes
even faster than "select 1 from dual".
And the main problem is:
4 - Your JDBCDataSource doesn't seem to be a transactional one, so any
application code that gets connections from that, will get independent
connections each time, and their work will not be included in any WLS
controlled transactions. You want to make/use a JDBCTxDataSource.
Joe