Hello, I've been looking at implementing two phase commit for the psycopg2 driver for PostgreSQL. It was suggested that I bring up the issue on this list to see if there were any suggestions about what form the API should take.
The API from the initial patch I produced stuck pretty close to the PostgreSQL API, adding three methods to the connection object: prepare_transaction(xid) - prepare the transaction, using the given ID. This closes off the transaction, allowing a new one to be started (if needed). commit_prepared(xid) - commit a previously prepared transaction . Must be called outside of a transaction (i.e. no execute() calls since the last commit/rollback). rollback_prepared(xid) - rollback a previously prepared transaction. The idea being that this should be enough to plug psycopg2 into a transaction manager such as Zope's transaction module or similar. I understand that this API might not be implementable by other database adapters, which brings up the question: what would be a good API? >From a quick search, I found two other adapters implementing 2pc both with incompatible APIs: kinterbasdb implements a Connection.prepare() method, which performs the first phase and causes a subsequent commit() or rollback() to complete that transaction. Transaction identifiers are not exposed by the API. pymqi provides a patch to the DCOracle2 adapter. It doesn't seem to add any explicit API to the connection object, but DCOracle2 does have an incompatible prepare() method used for prepared statements. So is there any recommendations for what a two-phase commit API should look like? James. _______________________________________________ DB-SIG maillist - DB-SIG@python.org http://mail.python.org/mailman/listinfo/db-sig
