diff --git a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/metadata/fetcher/cache/TableDeviceLastCache.java b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/metadata/fetcher/cache/TableDeviceLastCache.java
index 02f02980510e..fc0c9ddb7d9f 100644
--- a/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/metadata/fetcher/cache/TableDeviceLastCache.java
+++ b/iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/metadata/fetcher/cache/TableDeviceLastCache.java
@@ -80,7 +80,7 @@ public TSDataType getDataType() {
       Optional.of(new Pair<>(OptionalLong.empty(), null));
   public static final TimeValuePair EMPTY_TIME_VALUE_PAIR =
       new TimeValuePair(Long.MIN_VALUE, EMPTY_PRIMITIVE_TYPE);
-  public static final TimeValuePair PLACEHOLDER_TIME_VALUE_PAIR =
+  private static final TimeValuePair PLACEHOLDER_TIME_VALUE_PAIR =
       new TimeValuePair(Long.MIN_VALUE, EMPTY_PRIMITIVE_TYPE);
 
   // Time is seen as "" as a measurement