Twophase Support for MSSQL

[Former user]

I'm using both a MySQL and a MSSQL server for an application, so I added the following code to the MSSQLDialect to get twophase support.

Additionally, I changed the default dialect's create_xid method, which returns a transaction ID, to reference and truncate to max_identifier_length (it was failing due to this with pymssql) and to not use any underscores in the name (which, I believe, fails with MSSQL in general).

Both patches attached, against current trunk (r3643). They work with an application I have running using pymssql, but are untested with pyobdc or adodbapi as I don't have environments for them.

[Former user]

Add twophase support for the MSSQL dialect

[Former user]

Remove underscores from create_xid, and have it respect max_identifier_length

[Mike Bayer]

i can patch these but it would be nice to see if someone can test on a few environments...

[Former user]

I'm using MSSQL 2005 with adodbapi. Would that help?

[Former user]

Savepoint support and two phase transactions using the jdbc XA procs

[Former user]

mssql.diff makes the following changes:

• savepoint support

• real two phase support using the jdbc XA stored procs (see MSSQLTwoPhaseCommit)

• turns implicit transactions off and manually begins normal transactions.

Laurence ([e-mail])

[Former user]

(This is tested with pyodbc, MSSQL 2005 and the sqljdbc 1.2 driver's dll)

[Former user]

Savepoint support - engine/transaction tests pass

[Former user]

Two phase support requires sending a specific TDS packet (see MSSQLTwoPhaseCommit) in order to enlist a connection in the DTC transaction, so this part is on hold until I can work out how (and if) I can manage this.

The savepoint support is however working and tests pass (with pyodbc and mssql 2005).

Laurence ([e-mail])

[Mike Bayer]

laurence -

does this invalidate the mssql.diff patch you attached ?

[Former user]

Yes, I think I need to add methods to the pyodbc driver before two phase commit can work.

Laurence

[Mike Bayer]

pushing this to 0.6 for the dialect refactor, but 0.5.xx code will be accepted as well.

[Mike Bayer]

For now I've just turned on the already present savepoint functionality, that's in 58e692d76bbea84667609a4ceb828dcf43571f6e.

As far as two-phase, I've reviewed the notes on the above mentioned wiki page and it appears 2-phase is tremendously complex and not really implemented. This ticket can of course be reopened if there's interest/progress on getting 2-phase to work but I don't see this happening now.