In WebSphere, connecting to different XA datasources (all oracle) is ok. For discussion purposes, let's call it connectionA and connectionB.
However, when I mix the connection wherein one datasource is db2 and the other is oracle (connectionA=DB2, connectionB=oracle), I keep on having this error no matter how the connection pool or the RDBMS (oracle) is set:
WTRN0078E: An attempt by the transaction manager to call start on a transactional resource has resulted in an error. The error code was XAER_RMERR. The exception stack trace follows: oracle.jdbc.xa.OracleXAException.
It sounds like either the db2 data source is a local data source, or it uses a transaction manager that you don't have access to for some reason. Not familiar with db2 specifics, but I know with sqlserver you have to jump through some significant hoops on some wintel platforms (e.g. xp) to get access to the transaction manager in order to have XA work.
Reid - SCJP2 (April 2002)
Joined: Feb 15, 2006
Found the answer to the problem. The problem lies in the transaction isolation level supported by WebSphere and in conjunction with DB2 and Oracle. More info on this site: