Ability to set fsync=off with environment variable

[intellix]

It would be a nice convenience if you could set fsync=off for when using this image in integration tests due to how much of a performance boost it gives (in my case it goes from 300sec -> 40sec) using an environment variable.

So instead of:

db:
  image: postgres
  command: -c fsync=off
  environment:
    - POSTGRES_USER=myuser
    - POSTGRES_PASSWORD=blahblah
    - POSTGRES_DB=mydb

It would be possible to do:

db:
  image: postgres
  environment:
    - POSTGRES_USER=myuser
    - POSTGRES_PASSWORD=blahblah
    - POSTGRES_DB=mydb
    - POSTGRES_FSYNC=off

I'd like to use command: -c fsync=off within my Gitlab CI/CD test step but you only really have access to the env vars for customisation. Currently my workaround is to use bitnami/postgresql which supports it

[tianon]

I'd like to use command: -c fsync=off within my Gitlab CI/CD test step but you only really have access to the env vars for customisation.

This used to be the case, but it's been since fixed: https://docs.gitlab.com/ee/ci/services/ 😄

[yosifkit]

Duplicate of #831. In general, we are unlikely to add more environment variables; specifically, we are not going to add a variable for anything that can be done via an argument to the postgres server binary.

[simplenotezy]

@yosifkit Using github actions or docker-compose, can you provide an example of how to disable fsync?

[simplenotezy]

Found: #149 for docker-compose - still curious about github actions

[tianon]

I think you might be able to accomplish this via options: (last I looked; https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#jobsjob_idservicesservice_idoptions); it would be nice if they'd add something more "official" for it -- I imagine there's probably a feature request hanging around somewhere.

However, you're probably going to have an easier time with an explicit step that runs a container directly with -d (easier to replicate/test locally, too).

[lancedikson]

@simplenotezy did you manage to find a work around this for Github Actions? I can't quickly find a way to apply the options param in the similar way it's used for the compose configuration — it says invalid argument "fsync=off" for "-c, --cpu-shares" flag: strconv.ParseInt: parsing "fsync=off": invalid syntax 😕