fix(server): ensure graph clear API does not clear meta table

Author: LYD031106

hugegraph-server/hugegraph-mysql/src/main/java/org/apache/hugegraph/backend/store/mysql/MysqlStore.java

@@ -24,6 +24,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
 
 import org.apache.hugegraph.backend.BackendException;
 import org.apache.hugegraph.backend.id.Id;
@@ -335,7 +336,7 @@ protected void clearTables() {
 
     protected void truncateTables() {
         Session session = this.sessions.session();
-        for (MysqlTable table : this.tables()) {
+        for (MysqlTable table : this.getTruncatedTables()) {
             table.truncate(session);
         }
     }
@@ -344,6 +345,14 @@ protected Collection<MysqlTable> tables() {
         return this.tables.values();
     }
 
+    protected Collection<MysqlTable> getTruncatedTables() {
+        // Exclude meta table to preserve system metadata during graph clear
+        return this.tables.entrySet().stream()
+                          .filter(e -> !(HugeType.META == e.getKey()))
+                          .map(Map.Entry::getValue)
+                          .collect(Collectors.toList());
+    }
+
     @Override
     protected final MysqlTable table(HugeType type) {
         assert type != null;
@@ -505,6 +514,7 @@ public String storedVersion() {
         @Override
         protected Collection<MysqlTable> tables() {
             List<MysqlTable> tables = new ArrayList<>(super.tables());
+            tables.add(this.meta);
             return tables;
         }
     }

hugegraph-server/hugegraph-test/src/main/java/org/apache/hugegraph/unit/mysql/BaseMysqlUnitTest.java

@@ -1,20 +1,18 @@
 /*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
  *
- *  * Licensed to the Apache Software Foundation (ASF) under one or more
- *  * contributor license agreements.  See the NOTICE file distributed with
- *  * this work for additional information regarding copyright ownership.
- *  * The ASF licenses this file to You under the Apache License, Version 2.0
- *  * (the "License"); you may not use this file except in compliance with
- *  * the License.  You may obtain a copy of the License at
- *  *
- *  *     http://www.apache.org/licenses/LICENSE-2.0
- *  *
- *  * Unless required by applicable law or agreed to in writing, software
- *  * distributed under the License is distributed on an "AS IS" BASIS,
- *  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- *  * See the License for the specific language governing permissions and
- *  * limitations under the License.
+ *     http://www.apache.org/licenses/LICENSE-2.0
  *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
  */
 
 package org.apache.hugegraph.unit.mysql;
@@ -49,12 +47,19 @@ public void setup() throws Exception {
     }
 
     @After
-    public void down(){
+    public void down() {
         if (this.provider != null) {
             try {
                 this.provider.close();
             } catch (Exception e) {
-                LOG.warn("Mysql provider close failed",e);
+                LOG.warn("Mysql provider close failed ", e);
+            }
+        }
+        if (this.sessions != null) {
+            try {
+                this.sessions.close();
+            } catch (Exception e) {
+                LOG.warn("Mysql sessions close failed ", e);
             }
         }
     }

hugegraph-server/hugegraph-test/src/main/java/org/apache/hugegraph/unit/mysql/MysqlTest.java

@@ -25,10 +25,11 @@
 import org.apache.hugegraph.testutil.Assert;
 import org.junit.Before;
 import org.junit.Test;
-import java.sql.PreparedStatement;
+
 import java.sql.SQLException;
 
-public class MysqlTest extends BaseMysqlUnitTest{
+public class MysqlTest extends BaseMysqlUnitTest {
+
     @Before
     public void setUp() throws Exception {
         super.setup();
@@ -44,67 +45,73 @@ public void testMysqlMetaVersion() throws SQLException {
         // Get sessions for direct table operations
         MysqlSessions.Session session = this.sessions.session();
         session.open();
-        
+
         // Get the actual table names from the store
         String vertexTable = "g_v";
         String edgeOutTable = "g_oe";
         String edgeInTable = "g_ie";
-        
+
         // Insert test vertex data directly using simple SQL
         String insertVertex = String.format(
-            "INSERT INTO %s (ID, LABEL, PROPERTIES, EXPIRED_TIME) VALUES ('test_vertex', 1, '{\"name\":\"test_vertex\"}', 0)",
-            vertexTable
+                "INSERT INTO %s (ID, LABEL, PROPERTIES, EXPIRED_TIME) VALUES ('test_vertex', 1, " +
+                "'{\"name\":\"test_vertex\"}', 0)",
+                vertexTable
         );
         session.execute(insertVertex);
-        
+
         // Insert test edge data directly using simple SQL
         String insertEdgeOut = String.format(
-            "INSERT INTO %s (OWNER_VERTEX, DIRECTION, LABEL, SUB_LABEL, SORT_VALUES, OTHER_VERTEX, PROPERTIES, EXPIRED_TIME) VALUES ('test_vertex', 0, 1, 0, '', 'target_vertex', '{\"weight\":1.0}', 0)",
-            edgeOutTable
+                "INSERT INTO %s (OWNER_VERTEX, DIRECTION, LABEL, SUB_LABEL, SORT_VALUES, " +
+                "OTHER_VERTEX, PROPERTIES, EXPIRED_TIME) VALUES ('test_vertex', 0, 1, 0, '', " +
+                "'target_vertex', '{\"weight\":1.0}', 0)",
+                edgeOutTable
         );
         session.execute(insertEdgeOut);
-        
+
         String insertEdgeIn = String.format(
-            "INSERT INTO %s (OWNER_VERTEX, DIRECTION, LABEL, SUB_LABEL, SORT_VALUES, OTHER_VERTEX, PROPERTIES, EXPIRED_TIME) VALUES ('target_vertex', 1, 1, 0, '', 'test_vertex', '{\"weight\":1.0}', 0)",
-            edgeInTable
+                "INSERT INTO %s (OWNER_VERTEX, DIRECTION, LABEL, SUB_LABEL, SORT_VALUES, " +
+                "OTHER_VERTEX, PROPERTIES, EXPIRED_TIME) VALUES ('target_vertex', 1, 1, 0, '', " +
+                "'test_vertex', '{\"weight\":1.0}', 0)",
+                edgeInTable
         );
         session.execute(insertEdgeIn);
 
         // Verify data exists by querying
         String selectVertex = String.format("SELECT * FROM %s WHERE ID = 'test_vertex'", vertexTable);
-        ResultSetWrapper vResult = session.select(selectVertex);
-        Assert.assertTrue("vertex data should exist", vResult.next());
-        vResult.close();
-        
-        String selectEdgeOut = String.format("SELECT * FROM %s WHERE OWNER_VERTEX = 'test_vertex' AND DIRECTION = 0", edgeOutTable);
-        ResultSetWrapper oeResult = session.select(selectEdgeOut);
-        Assert.assertTrue("out edge data should exist", oeResult.next());
-        oeResult.close();
-        
-        String selectEdgeIn = String.format("SELECT * FROM %s WHERE OWNER_VERTEX = 'target_vertex' AND DIRECTION = 1", edgeInTable);
-        ResultSetWrapper ieResult = session.select(selectEdgeIn);
-        Assert.assertTrue("in edge data should exist", ieResult.next());
-        ieResult.close();
+        String selectEdgeOut = String.format(
+                "SELECT * FROM %s WHERE OWNER_VERTEX = 'test_vertex' AND DIRECTION = 0",
+                edgeOutTable);
+        String selectEdgeIn = String.format(
+                "SELECT * FROM %s WHERE OWNER_VERTEX = 'target_vertex' AND DIRECTION = 1",
+                edgeInTable);
+        try (
+                ResultSetWrapper vResult = session.select(selectVertex);
+                ResultSetWrapper oeResult = session.select(selectEdgeOut);
+                ResultSetWrapper ieResult = session.select(selectEdgeIn);
+        ) {
+            Assert.assertTrue("vertex data should exist", vResult.next());
+            Assert.assertTrue("out edge data should exist", oeResult.next());
+            Assert.assertTrue("in edge data should exist", ieResult.next());
+        }
 
         // Execute truncate operation, clears all graph data but preserves system tables
         this.provider.truncate();
 
         // Verify system version remains unchanged after truncation
         String afterVersion = systemStore.storedVersion();
         Assert.assertNotNull("System metadata version should exist", afterVersion);
-        Assert.assertEquals("System metadata version should remain unchanged after truncation", beforeVersion, afterVersion);
+        Assert.assertEquals("System metadata version should remain unchanged after truncation",
+                            beforeVersion, afterVersion);
 
         // Verify data has been cleared
-        vResult = session.select(selectVertex);
-        Assert.assertFalse("vertex data should not exist", vResult.next());
-        vResult.close();
-        
-        oeResult = session.select(selectEdgeOut);
-        Assert.assertFalse("out edge data should not exist", oeResult.next());
-        oeResult.close();
-        
-        ieResult = session.select(selectEdgeIn);
-        Assert.assertFalse("in edge data should not exist", ieResult.next());
-        ieResult.close();
+        try (
+                ResultSetWrapper vResult = session.select(selectVertex);
+                ResultSetWrapper oeResult = session.select(selectEdgeOut);
+                ResultSetWrapper ieResult = session.select(selectEdgeIn);
+        ) {
+            Assert.assertFalse("vertex data should not exist", vResult.next());
+            Assert.assertFalse("out edge data should not exist", oeResult.next());
+            Assert.assertFalse("in edge data should not exist", ieResult.next());
+        }
     }
 }