Re: [PATCH] add concurrent_abort callback for output plugin

On 27.03.21 07:37, Amit Kapila wrote:
> Isn't it better to send prepare from the publisher in such a case so
> that subscribers can know about it when rollback prepared arrives?

That's exactly what this callback allows (among other options). It
provides a way for the output plugin to react to a transaction aborting
while it is being decoded. This would not be possible without this
additional callback.

Also note that I would like to retain the option to do some basic
protocol validity checks. Certain messages only make sense within a
transaction ('U'pdate, 'C'ommit). Others are only valid outside of a
transaction ('B'egin, begin_prepare_cb). This is only possible if the
output plugin has a callback for every entry into and exit out of a
transaction (being decoded). This used to be the case prior to 2PC
decoding and this patch re-establishes that.

> I think we have already done the same (sent prepare, exactly to handle
> the case you have described above) for *streamed* transactions.

Where can I find that? ISTM streaming transactions have the same issue:
the output plugin does not (or only implicitly) learn about a concurrent
abort of the transaction.

Regards

Markus