Horton

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

Tom Lane <tgl@sss.pgh.pa.us>

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, 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: 2022-03-29T18:37:31Z
Lists: pgsql-hackers 
Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, Mar 29, 2022 at 2:17 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> it's some random algorithm that they probably feel at liberty
>> to change.

> I guess that characterization surprises me. The man page for
> getopt_long() says this, and has for a long time at least on systems
> I've used:

Yeah, they say they follow the POSIX spec when you set POSIXLY_CORRECT.
What they don't spell out in any detail is what they do when you don't.
We know that it involves rearranging the argv[] array behind the
application's back, but not what the rules are for doing that.  In
particular, they must have some undocumented and probably not very safe
method for deciding which arguments are neither switches nor switch
arguments.

(Actually, if I recall previous discussions properly, another stumbling
block to doing anything here is that we'd also have to change all our
documentation to explain it.  Fixing the command line synopses would
be a mess already, and explaining the rules would be worse.)

			regards, tom lane

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.