Que upgrade does not set job job_schema_version to 2

[hlascelles]

We recently upgraded a project from to 2.x and found that all of the extant jobs were not being executed. It appears that the job_schema_version was still set to 1. This meant the new workers would ignore the enqueued jobs.

To get all the jobs running, we ran the following migration:

UPDATE que_jobs
SET job_schema_version = 2
WHERE job_schema_version IS DISTINCT FROM 2

I can imagine there is a rationale for this, such as to allow gradual no-downtime migration from one version to another. But it seems to have bitten a few people. Certainly us, a few here hlascelles/que-scheduler#412, and maybe this one #381.

Is there somewhere in the docs that we should put this as a debug step? And/or should it go in the migrate guide here: https://github.com/que-rb/que/blob/c0b0be8dc60ff18ea6a76a553ec38a273c303de3/docs/README.md#migrating

If nothing else, maybe this issue can live as a debug pointer.

[hlascelles]

This is probably related: #365

[ZimbiX]

This is by design. Did you miss the upgrade guide? https://github.com/que-rb/que/blob/master/CHANGELOG.md#200beta1-2022-03-24 I guess we assumed people would check the changelog when upgrading a major version

[ZimbiX]

Maybe we could add a startup check that if any jobs exist with job_schema_version of 1 then a warning is logged with a link to the upgrade guide.

[hlascelles]

Yes, looks like we (and a few others) missed it. Hmm, maybe it should be copied into the main docs.

I see the Migrating guide. Perhaps it can go in or near there?

And yes, a warning on startup sounds ideal!

[hlascelles]

Alternatively we can close this and just leave it as a documentation pointer. Many people are probably now upgraded. Up to you. 👍