Horton

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

Dilip Kumar <dilipbalaut@gmail.com>

View thread View on postgr.es
From: Dilip Kumar <dilipbalaut@gmail.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, 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: 2022-03-25T14:46:16Z
Lists: pgsql-hackers 
On Fri, Mar 25, 2022 at 7:41 PM Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Thu, Mar 24, 2022 at 12:12 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
> > Thanks, I have gone through your changes in comments and docs and those LGTM.
>
> It looks like this patch will need to be updated for Alvaro's commit
> 49d9cfc68bf4e0d32a948fe72d5a0ef7f464944e. The newly added test
> 029_replay_tsp_drops.pl fails with this patch applied. The standby log
> shows:
>
> 2022-03-25 10:00:10.022 EDT [38209] LOG:  entering standby mode
> 2022-03-25 10:00:10.024 EDT [38209] LOG:  redo starts at 0/3000028
> 2022-03-25 10:00:10.062 EDT [38209] FATAL:  could not create directory
> "pg_tblspc/16385/PG_15_202203241/16390": No such file or directory
> 2022-03-25 10:00:10.062 EDT [38209] CONTEXT:  WAL redo at 0/43EBD88
> for Database/CREATE_WAL_LOG: create dir 16385/16390
>
> On a quick look, I'm guessing that XLOG_DBASE_CREATE_WAL_LOG will need
> to mirror some of the logic that was added to the replay code for the
> existing strategy, but I haven't figured out the details.
>

Yeah, I think I got it, for XLOG_DBASE_CREATE_WAL_LOG now we will have
to handle the missing parent directory case, like Alvaro handled for
the XLOG_DBASE_CREATE(_FILE_COPY) case.


-- 
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.