On 2024-09-09, Lawrence D'Oliveiro <ldo@nz.invalid> wrote: > On Mon, 9 Sep 2024 09:13:40 -0000 (UTC), Jon Ribbens wrote: >> On 2024-09-08, Lawrence D'Oliveiro <ldo@nz.invalid> wrote: >>> On Sun, 8 Sep 2024 11:03:21 -0000 (UTC), Jon Ribbens wrote: >>>> What if there's an exception in your exception handler? I'd put the >>>> rollback in the 'finally' handler, so it's always called. If you've >>>> already called 'commit' then the rollback does nothing of course. >>> >>> In any DBMS worth its salt, rollback is something that happens >>> automatically if the transaction should fail to complete for any >>> reason. >>> >>> This applies for any failure reason, up to and including a program or >>> system crash. >> >> If it's a program or system crash, sure, but anything less than that - >> how would the database even know, unless the program told it? > > The database only needs to commit when it is explicitly told. Anything > less -- no commit.
So the Python code is half-way through a transaction when it throws a (non-database-related) exception and that thread of execution is aborted. The database connection returns to the pool, and is re-used by another thread which continues using it to perform a different sequence of operations ... ending in a COMMIT, which commits one-and-a-half transactions. -- https://mail.python.org/mailman/listinfo/python-list
