From: Jeff Davis <pgsql(at)j-davis(dot)com>
To: pgsql-hackers(at)postgresql(dot)org
Subject: Removing PD_ALL_VISIBLE
Date: 2012-11-22 02:24:57
Message-ID: 1353551097.11440.128.camel@sussancws0025
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Follow up to discussion:

I worked out a patch that replaces PD_ALL_VISIBLE with calls to
visibilitymap_test. It rips out a lot of complexity, with a net drop of
about 300 lines (not a lot, but some of that code is pretty complex).

The patch is quite rough, and I haven't yet added the code to keep the
VM buffer pins around longer, but I still don't see any major problems.
I'm fairly certain that scans will not be adversely affected, and I
think that inserts/updates/deletes should be fine as well.

The main worry I have with inserts/updates/deletes is that there will be
less spatial locality for allocating new buffers or for modifying
existing buffers. So keeping a pinned VM buffer might not help as much,
because it might need to pin a different one, anyway.

Adding to January commitfest, as it's past 11/15.

Jeff Davis

Attachment Content-Type Size
rm-pd-all-visible-20121121.patch.gz application/x-gzip 9.5 KB


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