Hi, On 2024-06-07 11:19:40 -0400, Tom Lane wrote: > Xiaoran Wang <fanfuxiao...@gmail.com> writes: > > I found that in enum XactEvent, there is 'XACT_EVENT_PREPARE' for > > 'prepare transaction', but there is no event for 'commit prepared' or > > 'rollback prepared'. > > On the whole, it seems like a good idea to me that those commands > don't invoke event triggers. It is a core principle of 2PC that > if 'prepare' succeeded, 'commit prepared' must not fail. Invoking a > trigger during the second step would add failure cases and I'm not > sure what value it has.
Event triggers? Isn't this about RegisterXactCallback? XACT_EVENT_COMMIT is called after the commit record has been flushed and the procarray has been modified. Thus a failure in the hook has somewhat limited consequences. I'd assume XACT_EVENT_COMMIT_PREPARED would do something similar. I suspect the reason we don't callback for 2pc commit/rollback prepared is simpl: The code for doing a 2pc commit prepared lives in twophase.c, not xact.c... Greetings, Andres Freund
