Feature flag: GetAllLFSPointers

[Feature flag] GetAllLFSPointers

What

Remove the get_all_lfs_pointers_go feature flag, from both Gitaly and GitLab

Owners

• Team: Gitaly
• Most appropriate slack channel to reach out to: #g_gitaly
• Best individual to reach out to: @johncai

Expectations

Latency improvement of the GetAllLFSPointers RPC: https://dashboards.gitlab.net/d/000000199/gitaly-feature-status?orgId=1&refresh=1m&var-environment=gprd&var-method=GetAllLFSPointers&var-prometheus=prometheus-01-inf-gprd&from=now-3h&to=now

What release does this feature occur in first?

%12.3

### What are we expecting to happen?

The Go implementation is called, which should decrease memory pressure on the Ruby sidecar. Latency might decrease a bit too.

What might happen if this goes wrong?

Delete the feature flag, to default to the Ruby implementation, or set the flag to 0.

What can we monitor to detect problems with this?

https://dashboards.gitlab.net/d/000000199/gitaly-feature-status?orgId=1&refresh=1m&var-environment=gprd&var-method=GetAllLFSPointers&var-prometheus=prometheus-01-inf-gprd&from=now-3h&to=now

Roll Out Steps

• Read the documentation of feature flags
• Enable on staging
• Test on staging
• Ensure that documentation has been updated
• Enable on GitLab.com for individual groups/projects listed above and verify behaviour
• Announce on the issue an estimated time this will be enabled on GitLab.com
• Enable on GitLab.com by running chatops command in #production
• Cross post chatops slack command to #support_gitlab-com and in your team channel
• Announce on the issue that the flag has been enabled
• Remove feature flag and add changelog entry