Re: New parameter RollbackError to control rollback behavior on error

On 03/26/2014 08:39 AM, Michael Paquier wrote:
> Hi all,
>
> The behavior of rollback when an error occurs on an handle is
> controlled by extending Protocol with "$PROTNUM-[0|1|2]" where:
> - 0 = let the application handle rollbacks
> - 1 = rollback whole transaction when an error occurs
> - 2 = rollback only statement that failed
> Using such an extension is somewhat awkward as a single string is used
> for two settings... The proposed attached patch adds a new parameter
> called RollbackError that allows to control the behavior of rollback
> on error with a different parameter.

Great!

Since we're designing a new user interface for this, let's try to make
it as user-friendly as possible:

* I'm not too fond of the RollbackError name. It sounds like "an error
while rolling back". I googled around and found out that DataDirect's
proprietary driver has the same option, and they call it
TransactionErrorBehavior. See
http://blogs.datadirect.com/2013/07/solution-unexpected-postgres-current-transaction-aborted-error.html.

* Instead of using 0-2 as the values, let's give them descriptive names.
Something like "none", "RollbackTransaction", "RollbackStatement".
(actually, we'll probably want to also allow the integers, to keep the
connection string short, as there is a size limit on that)

> I thought first about including that in my cleanup work for 9.4, but
> as this actually does not break the driver it may be worth adding it
> directly to master, explaining the patch attached here. Comments
> welcome. Note that if there are objections I do not mind adding that
> for the work that would be merged later to 9.4 builds.

Yeah, let's get this into the master branch before your big 9.4 cleanup
work.

- Heikki