Is there a limit on uid?

When uid is automatically defined manually, the following error occurred

grpc._channel._InactiveRpcError: <_InactiveRpcError of RPC that terminated with:
status = StatusCode.UNKNOWN
details = “Uid: [325687344] cannot be greater than lease: [1492476]”
debug_error_string = “{“created”:”@1633675607.650000000",“description”:“Error received from peer ipv4:”,“file”:“src/core/lib/surface/”,“file_line”:1068,“grpc_message”:“Uid: [325687344] cannot be greater than lease: [1492476]”,“grpc_status”:2}"

UIDs are leased by dgraph zero. If you do a mutation using blank nodes, then dgraph alpha leases the UID from zero. You can directly mutate on only those UIDs that are less than the max leased UID.
In case you want to mutate on a higher UID, you can lease them directly by using /assign endpoint on zero

Just to mention, UIDs are bounded by MaxUint64.