diff --git a/core/src/main/java/cn/edu/tsinghua/iot/benchmark/client/SchemaClient.java b/core/src/main/java/cn/edu/tsinghua/iot/benchmark/client/SchemaClient.java
index 3d00f3609..e86b04dc7 100644
--- a/core/src/main/java/cn/edu/tsinghua/iot/benchmark/client/SchemaClient.java
+++ b/core/src/main/java/cn/edu/tsinghua/iot/benchmark/client/SchemaClient.java
@@ -89,6 +89,7 @@ public Boolean call() {
 
         // register
         try {
+          // When the return value is non-empty, the registerSchema is successful.
           result = (null != dbWrapper.registerSchema(deviceSchemas));
         } catch (TsdbException e) {
           LOGGER.error("Register {} schema failed because ", config.getNET_DEVICE(), e);
diff --git a/iotdb-2.0/src/main/java/cn/edu/tsinghua/iot/benchmark/iotdb200/ModelStrategy/TreeStrategy.java b/iotdb-2.0/src/main/java/cn/edu/tsinghua/iot/benchmark/iotdb200/ModelStrategy/TreeStrategy.java
index b30b30570..5af0fc95e 100644
--- a/iotdb-2.0/src/main/java/cn/edu/tsinghua/iot/benchmark/iotdb200/ModelStrategy/TreeStrategy.java
+++ b/iotdb-2.0/src/main/java/cn/edu/tsinghua/iot/benchmark/iotdb200/ModelStrategy/TreeStrategy.java
@@ -32,7 +32,6 @@
 import cn.edu.tsinghua.iot.benchmark.iotdb200.IoTDB;
 import cn.edu.tsinghua.iot.benchmark.iotdb200.TimeseriesSchema;
 import cn.edu.tsinghua.iot.benchmark.iotdb200.utils.IoTDBUtils;
-import cn.edu.tsinghua.iot.benchmark.mode.BaseMode;
 import cn.edu.tsinghua.iot.benchmark.schema.schemaImpl.DeviceSchema;
 import cn.edu.tsinghua.iot.benchmark.tsdb.DBConfig;
 import cn.edu.tsinghua.iot.benchmark.tsdb.TsdbException;