Horton

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

Dilip Kumar <dilipbalaut@gmail.com>

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From: Dilip Kumar <dilipbalaut@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: 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: 2022-03-21T14:59:26Z
Lists: pgsql-hackers 
On Mon, Mar 21, 2022 at 7:07 PM Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Sun, Mar 20, 2022 at 1:34 AM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > I thought that way because IIUC, when we are locking the database
> > tuple we are ensuring that we are calling
> > ReceiveSharedInvalidMessages() right?   And IIUC
> > ReceiveSharedInvalidMessages(), is designed such a way that it will
> > consume all the outstanding messages and that's the reason it loops
> > multiple times if it identifies that the queue is full.  And if my
> > assumption here is correct then I think it is also correct that now we
> > only need to worry about anyone generating new invalidations and that
> > is not possible in this case.
>
> Well, I don't see how that chain of logic addresses my concern about
> sinval reset.
>
> Mind you, I'm not sure there's an actual problem here, because I tried
> testing the patch with debug_discard_caches=1 and nothing failed. But
> I still don't understand WHY nothing failed.

Okay, I see what you are saying.  Yeah this looks like a problem to me
as well.  I will try to reproduce this issue.

-- 
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com

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.