Re: fixing old_snapshot_threshold's time->xid mapping

Thomas Munro <thomas.munro@gmail.com>

From: Thomas Munro <thomas.munro@gmail.com>

To: Dilip Kumar <dilipbalaut@gmail.com>

Cc: Andres Freund <andres@anarazel.de>, Robert Haas <robertmhaas@gmail.com>, Kevin Grittner <kgrittn@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>

Date: 2020-08-14T00:52:29Z

Lists: pgsql-hackers

Attachments

v6-0001-Expose-oldSnapshotControl.patch (text/x-patch) patch v6-0001
v6-0002-contrib-old_snapshot-time-xid-mapping.patch (text/x-patch) patch v6-0002
v6-0003-Fix-bugs-in-MaintainOldSnapshotTimeMapping.patch (text/x-patch) patch v6-0003
v6-0004-Rewrite-the-snapshot_too_old-tests.patch (text/x-patch) patch v6-0004
v6-0005-Truncate-snapshot-too-old-time-map-when-CLOG-is-t.patch (text/x-patch) patch v6-0005
v6-0006-Add-TAP-test-for-snapshot-too-old-time-map-mainte.patch (text/x-patch) patch v6-0006

On Wed, Apr 22, 2020 at 5:39 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> -                       if (ts == update_ts)
> +                       if (ts >= update_ts)

Hi Dilip, I didn't follow this bit -- could you explain?

Here's a rebase.  In the 0004 patch I chose to leave behind some
unnecessary braces to avoid reindenting a bunch of code after removing
an if branch, just for ease of review, but I'd probably remove those
in a committed version.  I'm going to add this stuff to the next CF so
we don't lose track of it.

Commits

Remove the "snapshot too old" feature.
- f691f5b80a85 17.0 landed
Fix two bugs in MaintainOldSnapshotTimeMapping.
- 55b7e2f4d78d 14.0 landed
Add new 'old_snapshot' contrib module.
- aecf5ee2bb36 14.0 landed
Expose oldSnapshotControl definition via new header.
- f5ea92e8d620 14.0 landed