Guaranteed commit outcome in a distributed transaction processing system

Abstract

Techniques are described for providing a guaranteed commit outcome for global transactions that are optimized by deferring the commit processing to a resource manager, such as a DBMS, using optimizations. The 'Distributed Transaction Processing: The XA Specification' standard specification is ambiguous regarding commit outcomes for transactions managed by DBMS, resulting in wrong results for vendors implementing the standard. The techniques described provide a guaranteed commit outcome when using the optimizations, creating the opportunity for safe replay of global transactions when a communication error or timeout occurs between the transaction manager and the resource manager, and eliminating ambiguous transaction outcomes reaching applications and end users. Techniques described herein distinguished between global transactions in a session managed by a transaction manager, and those in the same session that are managed by the resource manager using the optimizations. The techniques provide a guaranteed commit outcome when the commit is managed by the resource manager, or when a transaction manager is managing the transaction. Switching between the different techniques to provide a guaranteed outcome occurs in a safe, performing, and silent manner, based on who controls the current transaction in a session. The solution includes one-phase processing, read only optimizations, and promotable transactions.