diff --git a/storage/innodb_plugin/include/log0log.h b/storage/innodb_plugin/include/log0log.h
index 135aeb69e2d..233714eb63a 100644
--- a/storage/innodb_plugin/include/log0log.h
+++ b/storage/innodb_plugin/include/log0log.h
@@ -825,7 +825,17 @@ struct log_struct{
 					written to some log group; for this to
 					be advanced, it is enough that the
 					write i/o has been completed for all
-					log groups */
+					log groups.
+					Note that since InnoDB currently
+					has only one log group therefore
+					this value is redundant. Also it
+					is possible that this value
+					falls behind the
+					flushed_to_disk_lsn transiently.
+					It is appropriate to use either
+					flushed_to_disk_lsn or
+					write_lsn which are always
+					up-to-date and accurate. */
 	ib_uint64_t	write_lsn;	/*!< end lsn for the current running
 					write */
 	ulint		write_end_offset;/*!< the data in buffer has
diff --git a/storage/innodb_plugin/log/log0log.c b/storage/innodb_plugin/log/log0log.c
index 86c9f9b4130..063581055e9 100644
--- a/storage/innodb_plugin/log/log0log.c
+++ b/storage/innodb_plugin/log/log0log.c
@@ -2013,7 +2013,7 @@ log_checkpoint(
 		return(TRUE);
 	}
 
-	ut_ad(log_sys->written_to_all_lsn >= oldest_lsn);
+	ut_ad(log_sys->flushed_to_disk_lsn >= oldest_lsn);
 
 	if (log_sys->n_pending_checkpoint_writes > 0) {
 		/* A checkpoint write is running */