Subject Re: [Firebird-Architect] Re: Is Firebird XA compliant?
Author Paul Beach
> > Ah. The firebird two-phase commit was implemented some time before
> > XA was designed. Jim looked at it a long time ago for Borland
> > and decided that there was some piece of state missing for XA,
> > but that it would be possible to implement the MicroSoft
> > alternative.
> That's what I supsected. My conclusion is that although Firebird has
> a 2PC protocol, it is not XA-compliant. I'm a bit worried now about
> the JayBird initiative, because they claim to provide XA semantics
> whereas Jim (or was it Paul?) concluded that this is not possible
> without adding some XA specific logic to the Firebird database engine.

Jim in conjunction with R&D at the time. Although Ann and my memories are
a little hazy on this (I don't still have the original e-mail thread unfortunately).
The main issue investigated was MTS support, with possible XA support for
the various other TP monitors. MTS support being a main priority.

I think that MTS was viable, but XA was more problematic, and neither
option was properly followed up. ISC being subsumed back into Borland
and our R&D budget was not as independent as it used it to be and people
involved left or got pushed elsewhere.

> I'm not claiming to be an expert on this matter, but I in my opinion,
> if you want to provide an XA compliant JDBC driver, you should:
> 1. Add the extra logic to the Firebird database engine required to
> make the database XA compliant.
> 2. Create a native XA switch that can be plugged into an XA compliant
> transaction manager, such as Tuxedo, and test if it is working.
> 3. Update the Firebird communication protocol so that it has verbs
> for all XA verbs specified by the X/Open XA specification (xa_open(),
> xa_close(), xa_start(), xa_end(), xa_prepare(), etc).
> 4. Implement the XA compliant JDBC driver. This should be really easy
> because you can simply map all XAResource methods to the XA verbs
> that are already there.

I believe you are corect in your thinking, but I would be interested in Jim's comments.
I would be also interested in hearing from the JayBird developers to see what approach they
are taking re. XA and how what they are doing solves the problem.

<<Any plans in this direction?>>

Not that I am aware of. Its a question of demand. If somebody wants it badly enough
they will either roll their sleeves up and write the code, or pay for the development work.

Paul Beach
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