The “coordinator” column indicates the method or protocol used to manage a transaction. In the output above, the local transaction $user_transaction does not have an external coordinator. The remote transaction taking place on caserv2 has the coordinator value “ASTC”. This indicates that the transaction is coordinated using native Adaptive Server coordination services, as described under Chapter 3, “Using Adaptive Server Transaction Coordination Services”.
See sp_transactions in the Adaptive Server Reference Manual for a complete list and description of possible coordinator values.
