Am 14.02.2020 um 20:36 schrieb Robert Haas:
On Fri, Feb 14, 2020 at 2:08 PM Dave Cramer <davecramer@postgres.rocks> wrote:
Well now you are asking the driver to re-interpret the results in a different
way than the server which is not what we tend to do.
The server throws an error we throw an error. We really aren't in the business
of re-interpreting the servers responses.
I don't really see a reason why the driver has to throw an exception
if and only if there is an ERROR on the PostgreSQL side. But even if
you want to make that rule for some reason, it doesn't preclude
correct behavior here. All you really need is to have con.commit()
return some indication of what the command tag was, just as, say, psql
would do.
I think, this would be an appropriate solution. PostgreSQL reports the
"unsuccessful" commit through the "ROLLBACK" status code and the driver
translates this into a Java SQLException, because this is the only way
to communicate the "non-successfullness" from the void commit() method.
Since the commit() was not successful, from the API point of view this
is an error and it is fine to report this using an exception.
Am 14.02.2020 um 21:07 schrieb Tom Lane:
Dave Cramer <davecramer@postgres.rocks> writes:
We have the same blast radius.
I have offered to make the behaviour requested dependent on a configuration
parameter but apparently this is not sufficient.
Nope, that is absolutely not happening. We learned very painfully, back
around 7.3 when we tried to put in autocommit on/off, that if server
behaviors like this are configurable then most client code has to be
prepared to work with every possible setting. The argument that "you can
just set it to work the way you expect" is a dangerous falsehood. I see
no reason to think that a change like this wouldn't suffer the same sort
of embarrassing and expensive failure that autocommit did.
Doing this in a (non-default) driver setting is not ideal, because I
expect do be notified *by default* from a database (driver) if a commit
was not successful (and since the API is void, the only notification
path is an exception). We already have a non-default option named
"autosafe", which fixes the problem somehow.
If we really need both behaviors ("silently ignore failed commits" and
"notify about failed commits") I would prefer adding a
backwards-compatible option
"silently-ignore-failed-commit-due-to-auto-rollback" (since it is a
really aburd setting from my point of view, since consistency is at risk
if this happens - the worst thing to expect from a database).
Regards, Bernhard
