2009/12/8 黄晓骋 :
> From the above, I think the tuple lock is unnecessary, because it uses
> transaction lock.
>
> Besides, tuple lock is unlocked after the tuple is updated but not after the
> transaction commits. I mean it's not 2PL.
It's a two step process. An update marks the tuple locked. Anoth
2009/12/7 黄晓骋 :
> Hello,
>
> I think in Postgresql, concurrency control acts like this:
>
> tuple's infomask shows if it is being updated. If it is being updated now,
> the latter transaction should reread the tuple and get the newer tuple.
> During the progress of getting the newer tuple, it must
