DBZ-1267 Order capture instances by create date

[grzegorz8]

No description provided.

[jpechane]

@grzegorz8 I am not really sure about this change. How the code will behave in case of clock skew? What if NTP client will sync time in such a way that it will go back in time? Will not we receive an incorrecto ordering of the events then?

[grzegorz8]

Yes, you are right. I haven't taken that into account.

[grzegorz8]

On the other hand, I expect that no-one creates capture instances so frequently for the same table that we should worry about clock issues.

NTP would slow down the clock rather that move backwards.
https://serverfault.com/questions/94683/will-ntp-drift-the-clock-backwards

[jpechane]

@grzegorz8 NTP was just an example, Generally relying on clock for event ordering is very risky. And also this would need to be tested for DST etc. Whotever can go wrong will go wrong ;-).

[grzegorz8]

Then none of the fields is perfectly reliable.

• start_lsn - good if we assume that capture instance is deleted relatively quick (in <= N days, where N is log retention period).
• createDate - good if capture instances are not created so frequently that time issues might complicate things.

I also checked object_id but it is just a random number.

[jpechane]

@grzegorz8 I think the option 1 is less risky as it is something that can be controlled way easier than time issues.

[grzegorz8]

Ok, so I am closing this PR.