Horton

Re: snapbuild woes

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Noah Misch <noah@leadboat.com>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, Erik Rijkers <er@xs4all.nl>, David Steele <david@pgmasters.net>, Petr Jelinek <petr.jelinek@2ndquadrant.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>, Craig Ringer <craig@2ndquadrant.com>, pgsql-hackers-owner@postgresql.org
Date: 2017-04-20T00:09:06Z
Lists: pgsql-hackers 
On 2017-04-17 21:16:57 -0700, Andres Freund wrote:
> I think we might need some more tests for this to be committable, so
> it might not become committable tomorrow.

I'm working on some infrastructure around this.  Not sure if it needs to
be committed, but it's certainly useful for evaluation.  Basically it's
a small UDF that:
1) creates a slot via walsender protocol (to some dsn)
2) imports that snapshot into yet another connection to that dsn
3) runs some query over that new connection

That makes it reasonably easy to run e.g. pgbench and continually create
slots, and use the snapshot to run queries "verifying" that things look
good.  It's a bit shoestring-ed together, but everything else seems to
require more code. And it's just test.

Unless somebody has a better idea?

- Andres

Commits

  1. Fix thinko introduced in 2bef06d516460 et al.

  2. Avoid superfluous work for commits during logical slot creation.

  3. Fix race condition leading to hanging logical slot creation.

  4. Don't use on-disk snapshots for exported logical decoding snapshot.

  5. Preserve required !catalog tuples while computing initial decoding snapshot.