Horton

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Commits

  1. Add comments on avoid reuse of parse-time snapshot

  2. Revert patch for taking fewer snapshots.

  3. Take fewer snapshots.

  1. [PATCH] Comments related to "Take fewer snapshots" and "Revert patch for taking fewer snapshots"

    Michail Nikolaev <michail.nikolaev@gmail.com> — 2020-02-10T09:42:46Z

    Hello, hackers.

Yesterday I have noticed that in simple protocol mode snapshot is
taken twice - first time for parsing/analyze and later for execution.

I was thinking it is a great idea to reuse the same snapshot. After
some time (not short) I was able to find this thread from 2011 with
exactly same idea (of course after I already got few % of performance
in POC):

https://www.postgresql.org/message-id/flat/CA%2BTgmoYqKRj9BozjB-%2BtLQgVkSvzPFWBEzRF4PM2xjPOsmFRdw%40mail.gmail.com

And it was even merged: "Take fewer snapshots" (
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=d573e239f03506920938bf0be56c868d9c3416da
)

But where is optimisation in the HEAD?

It absent because was reverted later in 2012 because of tricky reasons
( https://www.postgresql.org/message-id/flat/5075D8DF.6050500%40fuzzy.cz
) in commit "Revert patch for taking fewer snapshots." (
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=532994299e2ff208a58376134fab75f5ae471e41
)

I think it is good idea to add few comments to code related to the
topic in order to safe time for a next guy.

Comments-only patch attached.

Thanks,
Michail.

  2. Re: [PATCH] Comments related to "Take fewer snapshots" and "Revert patch for taking fewer snapshots"

    Alvaro Herrera <alvherre@2ndquadrant.com> — 2020-02-28T16:28:44Z

    On 2020-Feb-10, Michail Nikolaev wrote:

> I think it is good idea to add few comments to code related to the
> topic in order to safe time for a next guy.

Applied, thanks.

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