Resource managers

Resource managers are data source managers, such as database management systems (DBMSs), that participate in a global transaction. These resource managers track their activities at the local level in transaction log files. Additionally, they can prepare recovery information and acquire all of the necessary locks and resources to either commit or roll back transactions when instructed by the transaction manager. Often, the old and new data is saved in storage so that any commit or rollback instruction can be performed accurately, even after any failure in the system, including applications, the transaction manager, or the resource manager. The resource managers work in cooperation with the transaction manager to provide the client application with a guarantee of atomicity of the global transactions.