diff --git a/CHANGES b/CHANGES
index ca9bb5a9c0..9fb931506a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,5 @@
+2590.	[func]		Report zone/class of "diff with no effect". [RT #19542]
+
 2589.	[bug]		dns_db_unregister() failed to clear '*dbimp'.
 		        [RT #19626]
 
diff --git a/lib/dns/diff.c b/lib/dns/diff.c
index 2c2c531b28..a64da709d6 100644
--- a/lib/dns/diff.c
+++ b/lib/dns/diff.c
@@ -15,7 +15,7 @@
  * PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: diff.c,v 1.20 2009/01/05 23:47:53 tbox Exp $ */
+/* $Id: diff.c,v 1.21 2009/04/30 06:53:10 marka Exp $ */
 
 /*! \file */
 
@@ -387,10 +387,22 @@ diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver,
 				 * from a server that is not as careful.
 				 * Issue a warning and continue.
 				 */
-				if (warn)
+				if (warn) {
+					char classbuf[DNS_RDATATYPE_FORMATSIZE];
+					char namebuf[DNS_NAME_FORMATSIZE];
+
+					dns_name_format(dns_db_origin(db),
+							namebuf,
+							sizeof(namebuf));
+					dns_rdataclass_format(dns_db_class(db),
+							      classbuf,
+							      sizeof(classbuf));
 					isc_log_write(DIFF_COMMON_LOGARGS,
 						      ISC_LOG_WARNING,
-						      "update with no effect");
+						      "%s/%s: update with no "
+						      " effect", namebuf,
+						      classbuf);
+				}
 			} else if (result == DNS_R_NXRRSET) {
 				/*
 				 * OK.