Currenlty in verify we add that as query metadata in specifications:

specs/validate_drp/cfht_ugrizy/base.yaml

  dataset_repo_url: 'https://github.com/lsst/validation_data_cfht.git'

  dataset_name: 'validation_data_cfht'

  visits: [849375, 850587]

  ccds: [12, 13, 14, 21, 22, 23]

Simon Krughoff:
I am really concerned about putting actual visits and ccds in the spec. I'd much rather specify a tag on the dataset that specifies the subset to be used. That tag can have a central definition. Since we don't actually use this info (as far as I know), I'd prefer to leave it out rather than having it in two places that can get out of sync.

I know tags for subsets isn't currently possible, but it will be available in the GEN3 system.

Angelo Fausti
Right, I'll open a ticket to revisit this when time comes. At least adding visits and ccds to query metadata in specs is consistent with adding filter_name for now. This is also related with the definition of datasets we need in SQuaSH.