dtm lock timeout period

dtm lock timeout period sets the maximum amount of time, in seconds, that a distributed transaction branch waits for lock resources to become available.

Summary Information

Default value

300 (seconds)

Valid values

1 – 2147483647 (seconds)



Display level


Required role

System administrator

Configuration group

DTM Administration

After this time has passed, SAP ASE considers the transaction to be in a deadlock situation, and rolls back the transaction branch that triggered the deadlock. This ultimately rolls back the entire distributed transaction.

Distributed transactions may potentially deadlock themselves if they propagate a transaction to a remote server, and in turn, the remote server propagates a transaction back to the originating server (described in the figure below). The work of distributed transaction “dxact1” is propagated to SAP ASE 2 via “rpc1.” SAP ASE 2 then propagates the transaction back to the coordinating server via “rpc2.” “rpc2” and “dxact1” share the same gtrid but have different branch qualifiers, so they cannot share the same transaction resources. If “rpc2” is awaiting a lock held by “dxact1,” a deadlock situation exists.

Distributed transaction deadlock
Graphic describing how a transaction deadlock occurs using the flow of RPC’s from the first Adaptive Server to the second. This process is described in the text of the book.

SAP ASE cannot detect interserver deadlocks. Instead, it relies on dtm lock timeout period. In the figure above, after dtm lock timeout period has expired, the transaction created for “rpc2” is aborted. This causes SAP ASE 2 to report a failure in its work, and “dxact1” is ultimately aborted as well.

The value of dtm lock timeout period applies only to distributed transactions. Local transactions may use a lock timeout period with the server-wide lock wait period parameter.

Note: SAP ASE does not use dtm lock timeout period to detect deadlocks on system tables.