HDDS-7282. Add EstimatedKeyCount metrics for SCM DB

hadoop-hdds/framework/src/main/java/org/apache/hadoop/hdds/scm/metadata/SCMMetadataStoreMXBean.java

@@ -0,0 +1,29 @@
+/*
+ * 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.
+ */
+package org.apache.hadoop.hdds.scm.metadata;
+
+/**
+ * JMX interface for the SCM Metadata Store.
+ */
+public interface SCMMetadataStoreMXBean {
+
+  /**
+   * Estimated key count for each column family.
+   */
+  String getEstimatedKeyCount();
+}

hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/metadata/SCMMetadataStoreImpl.java

@@ -21,6 +21,9 @@
 import java.io.IOException;
 import java.math.BigInteger;
 import java.security.cert.X509Certificate;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.stream.Collectors;
 
 import com.google.protobuf.ByteString;
 import org.apache.hadoop.hdds.conf.OzoneConfiguration;
@@ -57,15 +60,19 @@
 import static org.apache.hadoop.hdds.scm.metadata.SCMDBDefinition.META;
 import static org.apache.hadoop.ozone.OzoneConsts.DB_TRANSIENT_MARKER;
 
+import org.apache.hadoop.metrics2.util.MBeans;
 import org.apache.ratis.util.ExitUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import javax.management.ObjectName;
+
 /**
  * A RocksDB based implementation of SCM Metadata Store.
  *
  */
-public class SCMMetadataStoreImpl implements SCMMetadataStore {
+public class SCMMetadataStoreImpl implements SCMMetadataStore,
+    SCMMetadataStoreMXBean {
 
   private Table<Long, DeletedBlocksTransaction> deletedBlocksTable;
 
@@ -100,6 +107,9 @@ public class SCMMetadataStoreImpl implements SCMMetadataStore {
   private DBStore store;
   private final OzoneConfiguration configuration;
 
+  private ObjectName mxBean;
+  private Map<String, Table<?, ?>> tableMap = new ConcurrentHashMap<>();
+
   /**
    * Constructs the metadata store and starts the DB Services.
    *
@@ -190,6 +200,9 @@ public void start(OzoneConfiguration config)
 
       checkTableStatus(statefulServiceConfigTable,
           STATEFUL_SERVICE_CONFIG.getName());
+
+      mxBean = MBeans.register("SCMMetadataStore", "SCMMetadataStoreImpl",
+          this);
     }
   }
 
@@ -199,6 +212,10 @@ public void stop() throws Exception {
       store.close();
       store = null;
     }
+    if (mxBean != null) {
+      MBeans.unregister(mxBean);
+      mxBean = null;
+    }
   }
 
   @Override
@@ -313,6 +330,20 @@ private void checkTableStatus(Table table, String name) throws IOException {
       LOG.error(String.format(logMessage, name));
       throw new IOException(String.format(errMsg, name));
     }
+    tableMap.put(name, table);
+  }
+
+  @Override
+  public String getEstimatedKeyCount() {
+    return tableMap.entrySet().stream().map(e -> {
+      try {
+        return e.getKey() + " : " + e.getValue().getEstimatedKeyCount();
+      } catch (IOException ex) {
+        ex.printStackTrace();
+      }
+      return "N/A";
+    }).collect(
+        Collectors.joining(", "));
   }
 
 }

hadoop-hdds/server-scm/src/test/java/org/apache/hadoop/hdds/scm/metadata/TestSCMMetadataStoreImpl.java

@@ -0,0 +1,62 @@
+/**
+ * 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.
+ */
+
+package org.apache.hadoop.hdds.scm.metadata;
+
+import org.apache.hadoop.hdds.conf.OzoneConfiguration;
+import org.apache.hadoop.ozone.container.common.SCMTestUtils;
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.IOException;
+import java.nio.file.Path;
+
+
+/**
+ * Testing of SCMMetadataStoreImpl.
+ */
+public class TestSCMMetadataStoreImpl {
+  private OzoneConfiguration conf;
+  private SCMMetadataStore scmMetadataStore;
+
+  @BeforeEach
+  public void setUp(@TempDir Path tempDir) throws Exception {
+    conf = SCMTestUtils.getConf();
+
+    scmMetadataStore = new SCMMetadataStoreImpl(conf);
+    scmMetadataStore.start(conf);
+  }
+
+  @Test
+  public void testEstimatedKeyCount() {
+    Assertions.assertTrue(((SCMMetadataStoreImpl) scmMetadataStore)
+        .getEstimatedKeyCount().contains("sequenceId : 0"));
+
+    try {
+      scmMetadataStore.getSequenceIdTable().put("TestKey", 1L);
+    } catch (IOException e) {
+      // Ignore
+    }
+
+    Assertions.assertFalse(((SCMMetadataStoreImpl) scmMetadataStore)
+        .getEstimatedKeyCount().contains("sequenceId : 0"));
+  }
+
+}