diff --git a/proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/handler/distsql/rdl/storage/unit/UnregisterStorageUnitBackendHandler.java b/proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/handler/distsql/rdl/storage/unit/UnregisterStorageUnitBackendHandler.java
index 80df2fc3e17dd0..f2da5e6dbaf8f9 100644
--- a/proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/handler/distsql/rdl/storage/unit/UnregisterStorageUnitBackendHandler.java
+++ b/proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/handler/distsql/rdl/storage/unit/UnregisterStorageUnitBackendHandler.java
@@ -71,8 +71,8 @@ public void checkSQLStatement(final String databaseName, final UnregisterStorage
     }
     
     private void checkExisted(final String databaseName, final Collection<String> storageUnitNames) {
-        Map<String, NewStorageUnitMetaData> storageUnits = ProxyContext.getInstance().getDatabase(databaseName).getResourceMetaData().getStorageUnitMetaData().getMetaDataMap();
-        Collection<String> notExistedStorageUnits = storageUnitNames.stream().filter(each -> !storageUnits.containsKey(each)).collect(Collectors.toList());
+        Map<String, NewStorageUnitMetaData> metaDataMap = ProxyContext.getInstance().getDatabase(databaseName).getResourceMetaData().getStorageUnitMetaData().getMetaDataMap();
+        Collection<String> notExistedStorageUnits = storageUnitNames.stream().filter(each -> !metaDataMap.containsKey(each)).collect(Collectors.toList());
         ShardingSpherePreconditions.checkState(notExistedStorageUnits.isEmpty(), () -> new MissingRequiredStorageUnitsException(databaseName, notExistedStorageUnits));
     }