Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Ashutosh Sharma <ashu.coek88@gmail.com>
Cc: Dilip Kumar <dilipbalaut@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: 2022-03-15T16:47:22Z
Lists: pgsql-hackers 
On Tue, Mar 15, 2022 at 12:30 PM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
>
> Few comments on the latest patch:
>
> -               /* We need to construct the pathname for this database */
> -               dbpath = GetDatabasePath(xlrec->dbid, xlrec->tsid);
> +               if (xlrec->dbid != InvalidOid)
> +                       dbpath = GetDatabasePath(xlrec->dbid, xlrec->tsid);
> +               else
> +                       dbpath = pstrdup("global");
>
> Do we really need this change? Is GetDatabasePath() alone not capable
> of handling it?

Well, I mean, that function has a special case for
GLOBALTABLESPACE_OID, but GLOBALTABLESPACE_OID is 1664, and InvalidOid
is 0.

> I think we can shorten these function names to probably
> ScanSourceDBPgClassRel(), ScanSourceDBPgClassTuple() and likewise?

We could, but I don't think it's an improvement.

-- 
Robert Haas
EDB: 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.