DrTM durability

 Assume the database configuration depicted in the figure below:



There are three databases, one local (SALES), and two remote (HQ and MAINT). A user (SCOTT) is shown updating tables on all three databases using a distributed transaction over Oracle Net database links.

The following distributed transaction executed by scott updates the local sales database, the remote hq database, and the remote maint database:

UPDATE scott.dept@hq.us.acme.com
SET loc = 'REDWOOD SHORES'
WHERE deptno = 10;
UPDATE scott.emp
SET deptno = 11
WHERE deptno = 10;
UPDATE scott.bldg@maint.us.acme.com
SET room = 1225
WHERE room = 1163;
COMMIT;

Each database manager can decide to abort
Ensure that all the subtransactions are consistently committed or aborted

A remote access in DrTM is mainly done using one-sided RDMA operations for efficiency. DrTM currently preserves durability rather than availability in case of machine failures.