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NSLS-II / metadatastore

DEPRECATED: Incorporated into https://github.com/NSLS-II/databroker
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Notes about migration #200

Closed danielballan closed 8 years ago

danielballan commented 8 years ago

@arkilic's current approach add a configs key (de-normalizing the old "beamline configs" collection) and a migrated key, set to True. We should discuss if we are happy with those choices before we roll this out. Note that @tacaswell's MDS refactor introduces "version 0" for the present deployment and "version 1" for the service deployment, the main difference being uid as primary key and making configs embedded docs rather than stand-alone collection. Maybe we should favor version in place of "migrated"?

Also noting here that the refactored MDS can read both and finds them equal.

tacaswell commented 8 years ago

That version number does not show up anywhere in the database, it is purely a software side thing.

danielballan commented 8 years ago

Understood. My question for the group is, should a version key be added as part of the migration? I would say that that is better than migrated=True, which obviously won't help the next time we migrate. But maybe neither is needed.

ghost commented 8 years ago

migrated=True is a placeholder thing I added to the migration script in order to delete all migrated documents in case something goes wrong. We could alternatively use time or version. Let's get together early next week

danielballan commented 8 years ago

@arkilic That level of caution is appreciated. There are a couple other ways we could go here, as I think about it. Yeah, let's discuss in person.