On 03.11.2022 19:25, Tony Locke wrote:
Hello all, with pg8000 if autocommit is turned on while a transaction
is in progress, the autocommit behaviour only takes effect after the
current transaction has been explicitly committed or rolled back. Of
the options given, I'd go for option 1, raising an exception. I don't
like the idea of SQL statements being executed implicitly, which is
why I'd be against option 2.
That's a fair point, but please remember that no statements are
executed. The transaction control is completely with the driver library
and negotiated with the server (some use implicit statements for this,
but that's just a technical detail). In fact, users should /not/ use
transaction statements on connections managed by drivers. That's why we
have .rollback() and .commit() as separate APIs in the DB-API.
I think we've already settled on option 3, with the added note that many
database modules implement option 2. pg8000 would not be one of those,
but that's not a problem.
Writing to the attribute will be deprecated at the same time as
documenting it, so that we can prepare for DB-API 3.0 using a method
instead. This would then also address your concern.
A radical suggestion for DBAPI-3.0 would be to remove autocommit
completely. I think this would make the dbapi interface easier for
people to understand, because there would be no implicit SQL commands,
which is what I think confuses people. Of course the downside is less
portability, but I think people accept that if they change their
database a lot of things will be different, and autocommit is just one
of them. A higher level library such as SQLAlchemy could still emit
the correct SQL via the dialect so that users of SQLAlchemy wouldn't
need to know about autocommit.
That's not going to work out :-) Autocommit is essential for some
database operations, e.g. to avoid locking. Many databases also don't
permit running certain DDL statements inside transactions.
BTW: Django's default is to run in autocommit mode... not a particularly
good choice, but that's how it is:
https://docs.djangoproject.com/en/4.1/topics/db/transactions/#autocommit
Cheers,
--
Marc-Andre Lemburg
eGenix.com
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