Fix downgraded TsFileResource serialization

integration-test/src/test/java/org/apache/iotdb/confignode/it/regionmigration/pass/IoTDBRegionMigrateNormalIT.java

@@ -21,13 +21,21 @@
 
 import org.apache.iotdb.commons.utils.KillPoint.KillNode;
 import org.apache.iotdb.confignode.it.regionmigration.IoTDBRegionOperationReliabilityITFramework;
+import org.apache.iotdb.it.env.EnvFactory;
 import org.apache.iotdb.it.framework.IoTDBTestRunner;
 import org.apache.iotdb.itbase.category.ClusterIT;
 
+import org.junit.Assert;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 import org.junit.runner.RunWith;
 
+import java.sql.Connection;
+import java.sql.ResultSet;
+import java.sql.Statement;
+
+import static org.apache.iotdb.util.MagicUtils.makeItCloseQuietly;
+
 @Category({ClusterIT.class})
 @RunWith(IoTDBTestRunner.class)
 public class IoTDBRegionMigrateNormalIT extends IoTDBRegionOperationReliabilityITFramework {
@@ -40,4 +48,30 @@ public void normal1C2DTest() throws Exception {
   public void normal3C3DTest() throws Exception {
     successTest(2, 3, 3, 3, noKillPoints(), noKillPoints(), KillNode.ALL_NODES);
   }
+
+  @Test
+  public void migrateRegionWithDegradedTimeIndexTest() throws Exception {
+    // set TsFileResource memory to 0 to trigger degrading
+    EnvFactory.getEnv().getConfig().getCommonConfig().setQueryMemoryProportion("1:1:1:1:1:1:0");
+
+    successTest(1, 1, 1, 2, noKillPoints(), noKillPoints(), KillNode.ALL_NODES);
+
+    try (final Connection connection = makeItCloseQuietly(EnvFactory.getEnv().getConnection());
+        final Statement statement = makeItCloseQuietly(connection.createStatement())) {
+      assertCounts(statement, 1, 1);
+      statement.execute("INSERT INTO root.sg.d1(timestamp,speed,temperature) values(101, 3, 4)");
+      assertCounts(statement, 2, 2);
+    }
+  }
+
+  private static void assertCounts(
+      final Statement statement, final long expectedSpeedCount, final long expectedTemperatureCount)
+      throws Exception {
+    try (final ResultSet resultSet =
+        statement.executeQuery("select count(speed), count(temperature) from root.sg.d1")) {
+      Assert.assertTrue(resultSet.next());
+      Assert.assertEquals(expectedSpeedCount, resultSet.getLong(1));
+      Assert.assertEquals(expectedTemperatureCount, resultSet.getLong(2));
+    }
+  }
 }

iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/tsfile/TsFileResource.java

@@ -248,7 +248,7 @@ public synchronized void serialize() throws IOException {
 
   private void serializeTo(BufferedOutputStream outputStream) throws IOException {
     ReadWriteIOUtils.write(VERSION_NUMBER, outputStream);
-    timeIndex.serialize(outputStream);
+    getTimeIndexForSerialization().serialize(outputStream);
 
     ReadWriteIOUtils.write(maxPlanIndex, outputStream);
     ReadWriteIOUtils.write(minPlanIndex, outputStream);
@@ -276,6 +276,14 @@ private void serializeTo(BufferedOutputStream outputStream) throws IOException {
     ReadWriteIOUtils.write(isGeneratedByPipe, outputStream);
   }
 
+  private ITimeIndex getTimeIndexForSerialization() throws IOException {
+    if (!(timeIndex instanceof FileTimeIndex) || !resourceFileExists()) {
+      return timeIndex;
+    }
+
+    return buildDeviceTimeIndex();
+  }
+
   /** deserialize from disk */
   public void deserialize() throws IOException {
     try (InputStream inputStream = fsFactory.getBufferedInputStream(file + RESOURCE_SUFFIX)) {

iotdb-core/datanode/src/test/java/org/apache/iotdb/db/storageengine/dataregion/tsfile/TsFileResourceTest.java

@@ -69,7 +69,7 @@ public void tearDown() throws IOException {
     if (file.exists()) {
       FileUtils.delete(file);
     }
-    File resourceFile = new File(file.getName() + TsFileResource.RESOURCE_SUFFIX);
+    File resourceFile = new File(file.getPath() + TsFileResource.RESOURCE_SUFFIX);
     if (resourceFile.exists()) {
       FileUtils.delete(resourceFile);
     }
@@ -84,7 +84,21 @@ public void testSerializeAndDeserialize() throws IOException {
   }
 
   @Test
-  public void testDegradeAndFileTimeIndex() {
+  public void testSerializeDegradedTimeIndex() throws IOException {
+    tsFileResource.serialize();
+    tsFileResource.degradeTimeIndex();
+
+    tsFileResource.serialize();
+
+    TsFileResource derTsFileResource = new TsFileResource(file);
+    derTsFileResource.deserialize();
+    Assert.assertEquals(ITimeIndex.DEVICE_TIME_INDEX_TYPE, derTsFileResource.getTimeIndexType());
+    Assert.assertEquals(deviceToIndex.keySet(), derTsFileResource.getDevices());
+  }
+
+  @Test
+  public void testDegradeAndFileTimeIndex() throws IOException {
+    tsFileResource.serialize();
     Assert.assertEquals(ITimeIndex.DEVICE_TIME_INDEX_TYPE, tsFileResource.getTimeIndexType());
     tsFileResource.degradeTimeIndex();
     Assert.assertEquals(ITimeIndex.FILE_TIME_INDEX_TYPE, tsFileResource.getTimeIndexType());