Distributed Transaction Management within Adaptive Server tracks the state of a transaction in the local Adaptive Server/Component Integration Services, as well as in all remote servers participating in transactions. When a user application commits a transaction, the commit is propagated to all participating remote servers using Adaptive Server Transaction Coordinator (ASTC). The management of multisite transactions is handled by ASTC in cooperation with Component Integration Services. Component Integration Services registers new participating servers for each transaction, then turns over control of the transaction coordination to ASTC, which calls back into Component Integration Services to execute various commands for transaction management.
Component Integration Services version 12.5 introduces a powerful mechanism for supporting distributed transaction management transparently using only Adaptive Server, which supports transparent two-phase commit services between local and remote Adaptive Server 12.0 or later, involving both RPC and DML (select, insert, delete, update) operations. In version 12.0, transparent two-phase commit was limited to DTM-enabled Adaptive Server (12.0 and later). However, with Adaptive Server 12.5 and later, this limit has been removed and support for DTM-enabled DirectConnects has been provided. A DirectConnect indicates its ability to handle two-phase commit transactions in the capability response resulting from the sp_capabilities RPC; currently, only Direct Connect for Oracle supports the full DTM-enabled behavior that enables two-phase commits.
