Re: A few patches to clarify snapshot management

Nathan Bossart <nathandbossart@gmail.com>

From: Nathan Bossart <nathandbossart@gmail.com>

To: Heikki Linnakangas <hlinnaka@iki.fi>

Cc: "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>

Date: 2024-12-16T21:56:42Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Use ereport() rather than elog()
- 661f821ef0c3 19 (unreleased) landed
Revert GetTransactionSnapshot() to return historic snapshot during LR
- 27f20441c5e7 18.0 landed
- 50f770c3d92c 19 (unreleased) landed
Improve snapmgr.c comment
- 043745c3a01f 18.0 landed
Assert that a snapshot is active or registered before it's used
- 8076c00592e4 18.0 landed
Don't allow GetTransactionSnapshot() in logical decoding
- 1585ff7387db 18.0 landed
Remove unnecessary GetTransactionSnapshot() calls
- 952365cded63 18.0 landed
snapshot scalability: Don't compute global horizons while building snapshots.
- dc7420c2c927 14.0 cited

On Mon, Dec 16, 2024 at 12:06:33PM +0200, Heikki Linnakangas wrote:
> While working on the CSN snapshot patch, I got sidetracked looking closer
> into the snapshot tracking in snapmgr.c. Attached are a few patches to
> clarify some things.

I haven't yet looked closely at what you are proposing, but big +1 from me
for the general idea.  I recently found myself wishing for a lot more
commentary about this stuff [0].

[0] https://postgr.es/m/Z0dB1ld2iPcS6nC9%40nathan

-- 
nathan