Deleting documents locally while keeping them in server

Is there any way or best practices to delete documents locally while keeping them in the server?

Our users (Native Android and Phonegap (android/ios) app) will be creating about 300 documents per day plus about 300 edition so the local database will grow quickly. I’m thinking on a scenario where documents older than 3 months are deleted on the local database but they are still on server (I don’t want to lose that data). In case the user needs to look at old data, I will request them on demand. I’m assuming performances slow down when the amount of documents grow.

The first question is: Is this scenario viable? how?

I’m aware performance depends on hardware but is there any information about the recommended amount of local documents to have a great user experience and don’t build a slow app?

Thanks!

You can delete and purge them in the app and they will remain on the server. But the next time you do a pull replication, they will get synced down again. So you would also need to remove the user access from that channel.

This could perhaps work:

  • In the push replication make sure all the docs were pushed to Sync Gateway by checking the status
  • Toggle a property on the user’s Profile document for example to remove the user from the channel containing the docs you want to delete
  • Check that the update to the Profile was pushed by checking the replication status again
  • Delete and purge the documents

This way, the docs will be on the server and not local.

There could be a boolean property on the user’s Profile document for example. When the user toggles a switch on the UI, update that property. In the sync function, if the property is true/false, grant/remove the user access to the archive channel.

PS: Fyi, you can also specify a channel name in the pull replication.

James

One minor correction: deleting and purging are two different operations.
To do a purge, you simply purge, no reason to delete it first (and in fact,
that will have unwanted side effects for this use case)

http://developer.couchbase.com/mobile/develop/guides/couchbase-lite/native-api/document/index.html#purging-a-document

That’s not quite true. They’ll only get downloaded again if the pull replicator has to start over and do a ‘slow sync’, which rarely happens. But yes, you can’t rely on the document staying gone forever, if the client still has access to the server-side version.