Re: Understanding LAST_CONFLICT_FREE_TRANSACTION and TRANSACTIONS_COMMITTED_ALL_MEMBERS

[Pedro Gomes]

Hi Geert

While Fred answer is the correct one in pointing to the correct direction, I just wanted to clarify the behaviour.

If I read correctly, that table represents the values that your read for each member for LAST_CONFLICT_FREE_TRANSACTION?

Anyway, what we have to retain here is that Group Replication is at the end of the day a distributed state machine, i.e., all members receive the same info in the same order and are expected to perform the same actions.

So, when you send a transaction for execution everyone will agree that it was delivered to all members and each member carries on with its job. So, what can happen here is that because maybe your primary is a bit more overloaded, the secondary members are quicker at certification so that value is updated sooner there.

Same for TRANSACTIONS_COMMITTED_ALL_MEMBERS. This is a set calculated with info that members send to each other. So it might also be that the primary is a bit slower on the calculation of the set when it gets the info.

Cheers,
Pedro