diff --git a/pkg/logstructured/logstructured.go b/pkg/logstructured/logstructured.go
index 00749206..966ba6c9 100644
--- a/pkg/logstructured/logstructured.go
+++ b/pkg/logstructured/logstructured.go
@@ -437,7 +437,7 @@ func (l *LogStructured) Watch(ctx context.Context, prefix string, revision int64
 				wr.CompactRevision = compact
 				wr.CurrentRevision = rev
 			} else {
-				errc <- errors.New("failed to execute query in database")
+				errc <- server.ErrGRPCUnhealthy
 			}
 		}
 		cancel()
diff --git a/pkg/server/types.go b/pkg/server/types.go
index 2dd1f94a..b1c2b168 100644
--- a/pkg/server/types.go
+++ b/pkg/server/types.go
@@ -12,9 +12,10 @@ import (
 var (
 	ErrNotSupported = status.New(codes.InvalidArgument, "etcdserver: unsupported operations in txn request").Err()
 
-	ErrKeyExists = rpctypes.ErrGRPCDuplicateKey
-	ErrCompacted = rpctypes.ErrGRPCCompacted
-	ErrFutureRev = rpctypes.ErrGRPCFutureRev
+	ErrKeyExists     = rpctypes.ErrGRPCDuplicateKey
+	ErrCompacted     = rpctypes.ErrGRPCCompacted
+	ErrFutureRev     = rpctypes.ErrGRPCFutureRev
+	ErrGRPCUnhealthy = rpctypes.ErrGRPCUnhealthy
 )
 
 type Backend interface {