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: Ashutosh Sharma <ashu.coek88@gmail.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>, Robert Haas <robertmhaas@gmail.com>, Andrew Dunstan <andrew@dunslane.net>, Heikki Linnakangas <hlinnaka@iki.fi>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-02-14T16:00:43Z
Lists: pgsql-hackers 
On Mon, Feb 14, 2022 at 9:17 PM Ashutosh Sharma <ashu.coek88@gmail.com> wrote:
>
>
> Is it possible to see the WAL size generated by these two statements:
> UPDATE 70% of the tuple in the base table (dirty 70% of the shared
> buffers) && CREATE database using template DB (Actual test target).
> Just wanted to know if it can exceed the max_wal_size of 64GB.

I think we already know the wal size generated by creating a db with
an old and new approach.  With the old approach it is just one WAL log
and with the new approach it is going to log every single block of the
database.  Yeah the updating 70% of the database could have some
impact but for verification purposes I tested without the update and
still the create db with WAL log is taking almost the same time.  But
anyway when I test next time I will verify again that no force
checkpoint is triggered.

-- 
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.