Re: [COMMITTERS] pgsql: Add the "snapshot too old" feature

Kevin Grittner wrote:
> Add the "snapshot too old" feature

> src/backend/access/gin/ginbtree.c | 9 +-
> src/backend/access/gin/gindatapage.c | 7 +-
> src/backend/access/gin/ginget.c | 22 +-
> src/backend/access/gin/gininsert.c | 2 +-

I'm wondering about the TestForOldSnapshot call in scanPendingInsert().
Why do we apply it to the metapage buffer (line 1717 in master)?
Shouldn't we apply it to the pending-list pages themselves only, if any?
(If there are no pending-list pages, surely the age of the snapshot used
to read the metapage doesn't matter; and if there are, then the age of
the pending-list pages will fail the test.)

FWIW I like the "revert" commit, because it easily shows me in what
places you considered a snapshot-too-old test and decided not to add
one. Bare BufferGetPage calls (the current situation) don't indicate that.

--
Álvaro Herrera http://www.2ndQuadrant.com/
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