Disabling fsync

[simplenotezy]

I'd like to disable fsync - is there a way to do this with this image?

[ImreSamu]

Hi simplenotezy,

I'd like to disable fsync - is there a way to do this with this image?

these repo images are just an extension of the docker-library/postgres images so all upstream customization should work.

see https://github.com/docker-library/docs/blob/master/postgres/README.md#database-configuration

• "Use a custom config file ...."
• "Set options directly on the run line. ... "

example: the postgis/postgis:14-3.2

• source code is https://github.com/postgis/docker-postgis/blob/master/14-3.2/Dockerfile
• and based on FROM postgres:14-bullseye

So check the upstream repo:

• https://github.com/docker-library/postgres/search?q=fsync&type=issues
  • https://github.com/docker-library/postgres/issues/149#issuecomment-215619199 command: -c fsync=off
    • and this should work with the postgis/postgis images!

And working :

$ docker run -d --name postgis_fsyncoff -e POSTGRES_PASSWORD=mypw postgis/postgis:14-3.2  -c fsync=off -c shared_buffers=720MB -c max_connections=42

$ docker exec -ti postgis_fsyncoff psql -U postgres

psql (14.3 (Debian 14.3-1.pgdg110+1))
Type "help" for help.

postgres=# show fsync;
 fsync 
-------
 off
(1 row)

[Komzpa]

Side note, disabling fsync is usually a bad idea - disabling synchronous_commit brings the perf improvements without the risks instead.