Hi @Siva_R,
The crc64() macro has been added refer to Language Constructs | Couchbase Docs to suppres the common duplicate mutation for Sync Gateway to Eventing.
There is a workaround for all duplicate documents when using Sync Gateway on Eventing’s source bucket refer to this forum post Unable to deploy a source mutating Eventing Function when Sync Gateway is deployed on same source bucket.
If you re have issues or need more specific please feel free to DM me.
Best
Jon Strabala
Principal Product Manager - Server