Re: snapshot too old, configured by time

Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> writes:
> I disagree. A developer that sees an unadorned BufferGetPage() call
> doesn't stop to think twice about whether they need to add a snapshot
> test. Many reviewers will miss the necessary addition also. A
> developer that sees BufferGetPage(NO_SNAPSHOT_TEST) will at least
> consider the idea that the flag might be right; if that developer
> doesn't think about it, some reviewer may notice a new call with the
> flag and consider the idea that the flag may be wrong.

I'm unconvinced ...

> I understand the backpatching pain argument, but my opinion was the
> contrary of yours even so.

I merely point out that the problem came up less than ten days after
that patch hit the tree. If that does not give you pause about the
size of the back-patching problem we've just introduced, it should.

TBH, there is nothing that I like about this feature: not the underlying
concept, not the invasiveness of the implementation, nothing. I would
dearly like to see it reverted altogether. I do not think it is worth
the pain that the current implementation will impose, both on developers
and on potential users. Surely there was another way to get a similar
end result without mucking with things at the level of BufferGetPage.

regards, tom lane