Horton

Re: [Proposal] Fully WAL logged CREATE DATABASE - No Checkpoints

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, Ashutosh Sharma <ashu.coek88@gmail.com>, Maciek Sakrejda <m.sakrejda@gmail.com>, Bruce Momjian <bruce@momjian.us>, Alvaro Herrera <alvherre@alvh.no-ip.org>, Andrew Dunstan <andrew@dunslane.net>, Heikki Linnakangas <hlinnaka@iki.fi>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-03-30T23:36:59Z
Lists: pgsql-hackers 
Hi,

On 2022-03-29 11:55:05 -0400, Robert Haas wrote:
> I committed v6 instead.

I was just discussing the WAL prefetching patch with Thomas. A question in
that discussion made me look at the coverage of REDO for CREATE DATABASE:
https://coverage.postgresql.org/src/backend/commands/dbcommands.c.gcov.html

Seems there's currently nothing hitting the REDO for
XLOG_DBASE_CREATE_FILE_COPY (currently line 3019). I think it'd be good to
keep coverage for that. How about adding a
  CREATE DATABASE ... STRATEGY file_copy
to 001_stream_rep.pl?


Might be worth adding a test for ALTER DATABASE ... SET TABLESPACE at the same
time, this patch did affect that path in some minor ways. And, somewhat
shockingly, we don't have a single test for it.

- Andres

Commits

  1. When using the WAL-logged CREATE DATABASE strategy, bulk extend.

  2. Avoid using a fake relcache entry to own an SmgrRelation.

  3. Fix data-corruption hazard in WAL-logged CREATE DATABASE.

  4. initdb: When running CREATE DATABASE, use STRATEGY = WAL_COPY.

  5. Simplify a needlessly-complicated regular expression.

  6. In 020_createdb.pl, change order of command-line arguments.

  7. Add new block-by-block strategy for CREATE DATABASE.

  8. Fix replay of create database records on standby

  9. Refactor code for reading and writing relation map files.

  10. Replace RelationOpenSmgr() with RelationGetSmgr().

  11. Refactor the fsync queue for wider use.