Re: Changing WAL Header to reduce contention during ReserveXLogInsertLocation()

Simon Riggs <simon(at)2ndquadrant(dot)com> writes:
> I know the approach is new and surprising but I thought about it a lot
> before proposing it and I couldn't see any holes; still can't. Please
> give this some thought so we can get comfortable with this idea and
> increase performance as a result. Thanks.

The long and the short of it is that this is a very dangerous-looking
proposal, we are at the tail end of a development cycle, and there are
~100 other patches remaining in the commitfest that also have claims
on our attention in the short time that's left. If you're expecting
people to spend more time thinking about this now, I feel you're being
unreasonable.

Also, I will say it once more: this change DOES decrease robustness.
It's like blockchain without the chain aspect, or git commits without
a parent pointer. We are not only interested in whether individual
WAL records are valid, but whether they form a consistent series.
Cross-checking xl_prev provides some measure of confidence about that;
xl_curr offers none.

regards, tom lane