inconsistent database key format during upgrade #851
Description
Motivation
1.15.x changed the key format in the database. We have a conversion process to convert the local disk from the old format to the new one. However, during the upgrade, some data servers are still running the old version, while others are running the new version. There's an inconsistent format between them, and if the new leader is selected by the new format data server. The old version of the dataserver can't process the snapshot database correctly. (old version does not have encode/decode key logic)
And yes, that would be finally recovered, but it would still show inconsistent data for the client side during the upgrade.