Hi couch users,
I got a main database and a database per user.
A users Db is replicated to his device (mobile phone) - idea is as much
functionality should be available offline.
To simplify a bit, let's say i got documents of type "item" and of type
"image", each "item" may reference multiple "images" and each "image" may
be referenced by multiple "items".
When a user gets a new "item" from the main database, a daemon checks if
all referenced images are available for that user and triggers replication
of the images missing.
If a user still got images which aren't needed on his device anymore, i
want to delete them, why waste space on his device?
Here comes my problem:
Say he got the document "image1" in revision: "1-abc" and doesn't need it
anymore i will delete it, which creates {_id: 'image1', rev: '2-cde',
_deleted: true} if for some reason he needs "image1" again because it is
also referenced by a different "item" i will replicate {_id: 'image1', rev:
'1-abc', ./*.. */} from the main database to the users database again. The
users database "says" i know an ancestor of that document the revision
"2-cde" in that example and the document "image1" will not show up again.
One way to solve that by attaching the images directly to the "items" - but
we got ~7 million items sharing ~4000 images, so that would increase the db
size by much.
An other way is using purge to delete an image so it can be replicated
again, but it seams to be wrong to use purge for general application logic,
think it should be kind of last resort.
Any other ideas?
Thanks & regards,
Stefan
