Re: XLogInsert

Jeff Janes <jeff.janes@gmail.com> writes:
> If I read the code correctly, the only thing that is irrevocable is
> that it writes into
> rdt->next, and if it saved an old copy of rdt first, then it could
> revoke the changes just
> by doing rdt_old->next=NULL.  If that were done, then I think this
> code could be
> moved out of the section holding the WALInsertLock.

Hmm, I recall that the changes are ... or were ... more complex.
The tricky case I think is where we have to go back and redo the
block-backup decisions after discovering that the checkpoint REDO
pointer has just moved.

If you can get the work out of the WALInsertLock section for just a
few more instructions, it would definitely be worth doing.
        regards, tom lane