sg_allDocs_x1 is never scanned, it is auto create on each of my collections by Gateway sync. Do I need to keep it? Is there any good to have indexes for Gateway Sync ? I’m on the Cb Community edition.
The allDocs index is used to serve requests for /.../_all_docs and to build changes for the * channel.
We have plans to drop this index at some point in the future, since the utilization as you’ve found is pretty low, and we can achieve similar “all docs” results via other means.
I would recommend not removing SG’s indexes though despite low utilization, since they will just be re-created again next time a SG node starts up.