Hi Mike,
I'm effectively using cx-Oracle... but I didn't notice any deprecation
warning! Maybe it's because I'm still using release 8.0.1 (as I still need
Python 3.5 support)?
If you need anyone to test for cx-Oracle features, just ask!
Anyway, I'm also using other "no-transactional" databases (like
Elasticsearch indexes), for which I effectively just use a basic
datamanager to post data, without any need for synchronized transactions...
Best regards,
Thierry
--
https://www.ulthar.net -- http://pyams.readthedocs.io
Le mer. 27 janv. 2021 à 20:40, Mike Bayer a
écrit :
>
>
> On Wed, Jan 27, 2021, at 2:23 PM, Thierry Florac wrote:
>
> Hi,
> I'm actually using two databases connections: one is my "main" connection,
> opened on a ZODB (with RelStorage), and **sometimes** I have to open
> another connection on another database (and event more sometimes); the two
> transactions have to be synchronized: if one of them is aborted for any
> reason, the two transactions have to be aborted.
>
>
>
> OK, then two phase it is
>
> I have always thought that the two-phase transaction was created to handle
> this kind of use case, but if there is another better solution, I would be
> very happy to know about it!
>
>
> if you need the ORM to call prepare() then you need the XID and there you
> are.
>
> This is all stuff that I think outside of the Zope community (but still in
> Python) you don't really see much of. If someone's Flask app is writing to
> Postgresql and MongoDB they're just going to spew data out to mongo and not
> really worry about it, but that's becasue mongo doesn't have any 2pc
> support.It's just not that commonly used because we get basically
> nobody asking about it.
>
>
>
> @jonathan, I made a patch to Pyramid DebugToolbar that I pushed to Github
> and made a pull request. But I don't know how to provide a test case as a
> two-phase commit is not supported by SQLite...
> I'll try anyway to provide a description of a "method" I use to reproduce
> this!
>
>
> So interesting fact, it looks like you are using Oracle for 2pc, that's
> what that tuple is, and we currently aren't including Oracle 2pc in our
> test support as cx_Oracle no longer includes the "twophase" flag which I
> think we needed for some of our more elaborate tests. At the moment,
> create_xid() emits a deprecation warning. I've been in contact with Oracle
> devs and it looks like we should be supporting 2pc as I can get help from
> them now for things that aren't working. I've opened
> https://github.com/sqlalchemy/sqlalchemy/issues/5884 to look into this.
> you should have been seeing a deprecation warning in your logs all this
> time though.
>
>
>
>
>
> Best regards,
> Thierry
> --
> https://www.ulthar.net -- http://pyams.readthedocs.io
>
>
> Le mer. 27 janv. 2021 à 19:19, Mike Bayer a
> écrit :
>
>
>
>
> On Wed, Jan 27, 2021, at 8:32 AM, Thierry Florac wrote:
>
>
> Hi,
> I'm actually using SQLAlchemy with Pyramid and zope.sqlalchemy packages.
> My main database connection is a ZODB connection and, when required, I
> create an SQLAlchemy session which is joined to main transaction using this
> kind of code:
>
> * from *sqlalchemy.orm *import *scoped_session, sessionmaker
>
> * from *zope.sqlalchemy *import *register
> * from *zope.sqlalchemy.datamanager *import* join_transaction
>
> _engine = get_engine(*engine*, *use_pool*)
> if *use_zope_extension*:
> factory = scoped_session(sessionmaker(*bind*=_engine, *twophase*=
> *True*))
> else:
> factory = sessionmaker(*bind*=_engine, *twophase*=*True*)
> session = factory()
> if *use_zope_extension*:
> register(session, *initial_state*=*STATUS_ACTIVE*)
> if *join*:
> join_transaction(session, *initial_state*=*STATUS_ACTIVE*)
>
> Everything is working correctly!
>
> So my only question is that I also use Pyramid_debugtoolbar package, which
> is tracking many SQLAlchemy events, including two-phase commits
> transactions, and which in this context receives transaction IDs as a three
> values tuple instead of a simple string (like, for example: (4660,
> '12345678901234567890123456789012', '0009'),
> which is raising an exception)!
> Is it normal behaviour, and what does this value mean?
>
>
> I would ask if you really really want to use the "twophase=True" flag, and
> I would suggest turning it off if you aren't in fact coordinating against
> multiple RDBMS backends (and even if you are, maybe). I'm not really sure
> what that tuple is, I'd have to look but it seems likely to be related to
> the XID stuff, which is really not something anyone uses these days.
>
>
>
> Best regards,
> Thierry
>
> --
> https://www.ulthar.net -- http://pyams.readthedocs.io
>
>
> --
> SQLAlchemy -
> The Python SQL Toolkit and Object Relational Mapper
>
> http://www.sqlalchemy.org/
>
> To post example code, please provide an MCVE: Minimal, Complete, and
> Verifiable Example. See http://stackoverflow.com/help/mcve for a full
>
