Re: Historic snapshot doesn't track txns committed in BUILDING_SNAPSHOT state

Hi,

- I re-read your comments in [0] and it looks like you've concern about
- the 2 "if" I'm proposing above and the fast forward handling. Is that the case
- or is your fast forward concern unrelated to my proposals?

In your proposals, we will just return when fast forward. But I think we need
handle XLOG_HEAP2_NEW_CID or XLOG_HEAP_INPLACE even if we are fast
forwarding as it decides whether the snapshot will track the transaction or not.

During fast forward, if there is a transaction that generates XLOG_HEAP2_NEW_CID
but no XLOG_XACT_INVALIDATIONS(I'm not sure), the snapshot won't track this
transaction in your proposals, I think it's wrong from a build snapshot perspective.

Although we don't decode anything during fast forward, the snapshot might be
serialized to disk when CONSISTENT, it would be better to keep the snapshot correct.

- Not sure what happened but it looks like your reply in [0] is not part of the
- initial thread [1], but created a new thread instead, making the whole
- conversation difficult to follow.

I'm not sure what happened but I attach the new thread to the CF:

https://commitfest.postgresql.org/49/5029

--
Regards,
ChangAo Chen