Some TM eg MQ uses dual transport model. In this model, a
transaction, over transport A, is tied to a member from xa_start
to xa_end, but xa_prepare(readonly), xa_prepare plus xa_commit
or xa_rollback, or xa_rollback comes in over transport B,
possibly from another application process. If the end server is
zOS, Syncpoint manger (DB2 connect server) with connection
concentrator is required to support XA applications. Becuase of
the APAR, requests to end the transaction by
TM(xa_prepare,xa_commit,xa_rollback) was not forwarded to the
zDB2, and resrouces locked by the transaction were not released
on server, eventhough TM completed the transaction. When
application tried to run other transaction, resultsed SQLCODE
913 (deadlock, locktimeout)
The problem can only happen with DB2 Version 9.7 Fix Pack 5
client. |
****************************************************************
* USERS AFFECTED: *
* All users utilizing XA connections against DB2/z using DB2 *
* Version 9.7 Fix Pack 5 client. *
****************************************************************
* PROBLEM DESCRIPTION: *
* Because of the defect, DB2 Connection concentrator did not *
* switched out the connection at the end of transaction ie on *
* xa_commit/xa_rollback. The same connection was used to *
* receive new set to XA request instead of picking the agent *
* associated with XID. As wrong agent was used to process the *
* XID, it resulted NOTA on DB2 connect server (SYNCPOINT *
* manager). The request was not forwarded to the end server *
* (zOS) and transaction remain incomplete on zOS. When another *
* transaction (with different XID) tried to use the same *
* resources resulted with lock-timeout. . *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 9.7 Fix Pack 6. *
**************************************************************** |
