ashishkumar50 commented on code in PR #4880:
URL: https://github.com/apache/ozone/pull/4880#discussion_r1237934925


##########
hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/tasks/ScmTableCountTask.java:
##########
@@ -0,0 +1,217 @@
+/*
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.ozone.recon.tasks;
+
+import com.google.common.collect.Iterators;
+import org.apache.hadoop.hdds.utils.db.DBStore;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.TableIterator;
+import org.apache.hadoop.ozone.recon.scm.ReconScmTask;
+import org.apache.hadoop.ozone.recon.scm.ReconStorageContainerManagerFacade;
+import org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition;
+import org.hadoop.ozone.recon.schema.tables.daos.ReconTaskStatusDao;
+import org.hadoop.ozone.recon.schema.tables.daos.ScmTableCountDao;
+import org.hadoop.ozone.recon.schema.tables.pojos.ScmTableCount;
+import org.jooq.DSLContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Iterator;
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static 
org.apache.hadoop.hdds.scm.metadata.SCMDBDefinition.DELETED_BLOCKS;
+import static 
org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition.SCM_TABLE_COUNT_TABLE_NAME;
+
+
+/**
+ * Any background task that tracks SCM's table counts.
+ */
+public class ScmTableCountTask extends ReconScmTask {
+
+  private static final Logger LOG =
+      LoggerFactory.getLogger(ScmTableCountTask.class);
+
+  private final DBStore scmDBStore;
+  private final ScmTableCountDao scmTableCountDao;
+  private final DSLContext dslContext;
+  private final long interval;
+  private ReadWriteLock lock = new ReentrantReadWriteLock(true);
+  private static final long NANOSECONDS_IN_MILLISECOND = 1_000_000;
+
+  public ScmTableCountTask(ReconStorageContainerManagerFacade reconSCM,
+                           ReconTaskStatusDao reconTaskStatusDao,
+                           ReconTaskConfig reconTaskConfig,
+                           ScmTableCountDao scmTableCountDao,
+                           UtilizationSchemaDefinition schemaDefinition) {
+    super(reconTaskStatusDao);
+    this.scmDBStore = reconSCM.getScmDBStore();
+    this.scmTableCountDao = scmTableCountDao;
+    this.dslContext = schemaDefinition.getDSLContext();
+    this.interval = reconTaskConfig.getScmTableCountTaskInterval().toMillis();
+  }
+
+  @Override
+  protected synchronized void run() {
+    try {
+      while (canRun()) {
+        wait(interval);
+        runTableCountProcess();
+      }
+    } catch (Throwable t) {
+      LOG.error("Error while running ScmTableCountTask: {}", t);
+      if (t instanceof InterruptedException) {
+        Thread.currentThread().interrupt();
+      }
+    }
+  }
+
+  private void runTableCountProcess() {
+    try {
+      long startTime, endTime, duration, durationMilliseconds;
+      try {

Review Comment:
   We can merge both try into one. Don't see any benefit of two try catch block.



##########
hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/tasks/ScmTableCountTask.java:
##########
@@ -0,0 +1,217 @@
+/*
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.ozone.recon.tasks;
+
+import com.google.common.collect.Iterators;
+import org.apache.hadoop.hdds.utils.db.DBStore;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.TableIterator;
+import org.apache.hadoop.ozone.recon.scm.ReconScmTask;
+import org.apache.hadoop.ozone.recon.scm.ReconStorageContainerManagerFacade;
+import org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition;
+import org.hadoop.ozone.recon.schema.tables.daos.ReconTaskStatusDao;
+import org.hadoop.ozone.recon.schema.tables.daos.ScmTableCountDao;
+import org.hadoop.ozone.recon.schema.tables.pojos.ScmTableCount;
+import org.jooq.DSLContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Iterator;
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static 
org.apache.hadoop.hdds.scm.metadata.SCMDBDefinition.DELETED_BLOCKS;
+import static 
org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition.SCM_TABLE_COUNT_TABLE_NAME;
+
+
+/**
+ * Any background task that tracks SCM's table counts.
+ */
+public class ScmTableCountTask extends ReconScmTask {
+
+  private static final Logger LOG =
+      LoggerFactory.getLogger(ScmTableCountTask.class);
+
+  private final DBStore scmDBStore;
+  private final ScmTableCountDao scmTableCountDao;
+  private final DSLContext dslContext;
+  private final long interval;
+  private ReadWriteLock lock = new ReentrantReadWriteLock(true);
+  private static final long NANOSECONDS_IN_MILLISECOND = 1_000_000;
+
+  public ScmTableCountTask(ReconStorageContainerManagerFacade reconSCM,
+                           ReconTaskStatusDao reconTaskStatusDao,
+                           ReconTaskConfig reconTaskConfig,
+                           ScmTableCountDao scmTableCountDao,
+                           UtilizationSchemaDefinition schemaDefinition) {
+    super(reconTaskStatusDao);
+    this.scmDBStore = reconSCM.getScmDBStore();
+    this.scmTableCountDao = scmTableCountDao;
+    this.dslContext = schemaDefinition.getDSLContext();
+    this.interval = reconTaskConfig.getScmTableCountTaskInterval().toMillis();
+  }
+
+  @Override
+  protected synchronized void run() {
+    try {
+      while (canRun()) {
+        wait(interval);
+        runTableCountProcess();
+      }
+    } catch (Throwable t) {
+      LOG.error("Error while running ScmTableCountTask: {}", t);
+      if (t instanceof InterruptedException) {
+        Thread.currentThread().interrupt();
+      }
+    }
+  }
+
+  private void runTableCountProcess() {
+    try {
+      long startTime, endTime, duration, durationMilliseconds;
+      try {
+        int execute = 
dslContext.truncate(SCM_TABLE_COUNT_TABLE_NAME).execute();
+        LOG.info("Deleted {} records from {}", execute,
+            SCM_TABLE_COUNT_TABLE_NAME);
+      } catch (Exception e) {
+        LOG.error("An error occurred while truncating the table {}: {}",
+            SCM_TABLE_COUNT_TABLE_NAME, e.getMessage(), e);
+        return;
+      }
+      startTime = System.nanoTime();
+      processTableCount();
+      endTime = System.nanoTime();
+      duration = endTime - startTime;
+      durationMilliseconds = duration / NANOSECONDS_IN_MILLISECOND;
+      LOG.info(
+          "Elapsed Time in milliseconds for processTableCount() execution: {}",
+          durationMilliseconds);
+    } catch (Throwable t) {
+      LOG.error("Error while performing table count: {}", t);
+    }
+  }
+
+  /**
+   * Processes the table count by iterating over SCM tables and retrieving the
+   * counts of objects in each table. The counts are then stored in the Recon
+   * database.
+   *
+   * @throws IOException if an I/O error occurs during table count processing.
+   */
+  public void processTableCount() throws IOException {
+    // Acquire write lock
+    lock.writeLock().lock();
+    try {
+      // Initialize the object count map
+      Map<String, Long> objectCountMap = initializeCountMap();
+
+      // Iterate over SCM tables
+      for (String tableName : getTaskTables()) {
+        Table table = scmDBStore.getTable(tableName);
+
+        try (TableIterator keyIter = table.iterator()) {
+          // Retrieve the count of objects in the table
+          long count = Iterators.size(keyIter);
+          objectCountMap.put(getRowKeyFromTable(tableName), count);
+        } catch (IOException ioEx) {
+          LOG.error("Unable to populate SCM Table Count in Recon DB.", ioEx);
+        }
+      }
+
+      // Write the counts to the Recon db if the object count map is not empty
+      if (!objectCountMap.isEmpty()) {
+        writeCountsToDB(objectCountMap);
+      }
+
+      objectCountMap.clear();
+      LOG.info("Completed writing SCM table counts to DB.");
+    } finally {
+      // Release write lock
+      lock.writeLock().unlock();
+    }
+  }
+
+
+  /**
+   * Writes the object counts from the object count map to the Recon database.
+   *
+   * @param objectCountMap a map containing table names as keys and their 
object
+   *                       counts as values.
+   */
+  private void writeCountsToDB(Map<String, Long> objectCountMap) {
+    List<ScmTableCount> insertToDb = new ArrayList<>();
+
+    // Iterate over the object count map
+    for (Map.Entry<String, Long> entry : objectCountMap.entrySet()) {
+      // Create a new ScmTableCount object
+      ScmTableCount scmTableCountRecord = new ScmTableCount();
+      scmTableCountRecord.setTableName(entry.getKey());
+      scmTableCountRecord.setCount(entry.getValue());
+
+      // Add the ScmTableCount object to the list
+      insertToDb.add(scmTableCountRecord);
+    }
+    // Insert the list of ScmTableCount objects into the Recon database
+    scmTableCountDao.insert(insertToDb);
+  }
+
+  private Map<String, Long> initializeCountMap() throws IOException {
+    Collection<String> tables = getTaskTables();
+    Map<String, Long> objectCountMap = new HashMap<>(tables.size());
+    for (String tableName: tables) {
+      String key = getRowKeyFromTable(tableName);
+      objectCountMap.put(key, 0L);
+    }
+    return objectCountMap;
+  }
+
+
+  /**
+   * Returns the list of SCM tables to be processed by the task.
+   *
+   * @return the list of SCM tables to be processed by the task.
+   * @throws IOException if an I/O error occurs.
+   */
+  public Collection<String> getTaskTables() throws IOException {

Review Comment:
   This method cannot throw IOException. Please remove it.



##########
hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/tasks/ScmTableCountTask.java:
##########
@@ -0,0 +1,217 @@
+/*
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.ozone.recon.tasks;
+
+import com.google.common.collect.Iterators;
+import org.apache.hadoop.hdds.utils.db.DBStore;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.TableIterator;
+import org.apache.hadoop.ozone.recon.scm.ReconScmTask;
+import org.apache.hadoop.ozone.recon.scm.ReconStorageContainerManagerFacade;
+import org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition;
+import org.hadoop.ozone.recon.schema.tables.daos.ReconTaskStatusDao;
+import org.hadoop.ozone.recon.schema.tables.daos.ScmTableCountDao;
+import org.hadoop.ozone.recon.schema.tables.pojos.ScmTableCount;
+import org.jooq.DSLContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Iterator;
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static 
org.apache.hadoop.hdds.scm.metadata.SCMDBDefinition.DELETED_BLOCKS;
+import static 
org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition.SCM_TABLE_COUNT_TABLE_NAME;
+
+
+/**
+ * Any background task that tracks SCM's table counts.
+ */
+public class ScmTableCountTask extends ReconScmTask {
+
+  private static final Logger LOG =
+      LoggerFactory.getLogger(ScmTableCountTask.class);
+
+  private final DBStore scmDBStore;
+  private final ScmTableCountDao scmTableCountDao;
+  private final DSLContext dslContext;
+  private final long interval;
+  private ReadWriteLock lock = new ReentrantReadWriteLock(true);
+  private static final long NANOSECONDS_IN_MILLISECOND = 1_000_000;
+
+  public ScmTableCountTask(ReconStorageContainerManagerFacade reconSCM,
+                           ReconTaskStatusDao reconTaskStatusDao,
+                           ReconTaskConfig reconTaskConfig,
+                           ScmTableCountDao scmTableCountDao,
+                           UtilizationSchemaDefinition schemaDefinition) {
+    super(reconTaskStatusDao);
+    this.scmDBStore = reconSCM.getScmDBStore();
+    this.scmTableCountDao = scmTableCountDao;
+    this.dslContext = schemaDefinition.getDSLContext();
+    this.interval = reconTaskConfig.getScmTableCountTaskInterval().toMillis();
+  }
+
+  @Override
+  protected synchronized void run() {
+    try {
+      while (canRun()) {
+        wait(interval);
+        runTableCountProcess();
+      }
+    } catch (Throwable t) {
+      LOG.error("Error while running ScmTableCountTask: {}", t);
+      if (t instanceof InterruptedException) {
+        Thread.currentThread().interrupt();
+      }
+    }
+  }
+
+  private void runTableCountProcess() {
+    try {
+      long startTime, endTime, duration, durationMilliseconds;
+      try {
+        int execute = 
dslContext.truncate(SCM_TABLE_COUNT_TABLE_NAME).execute();
+        LOG.info("Deleted {} records from {}", execute,
+            SCM_TABLE_COUNT_TABLE_NAME);
+      } catch (Exception e) {
+        LOG.error("An error occurred while truncating the table {}: {}",
+            SCM_TABLE_COUNT_TABLE_NAME, e.getMessage(), e);
+        return;
+      }
+      startTime = System.nanoTime();
+      processTableCount();
+      endTime = System.nanoTime();
+      duration = endTime - startTime;
+      durationMilliseconds = duration / NANOSECONDS_IN_MILLISECOND;
+      LOG.info(
+          "Elapsed Time in milliseconds for processTableCount() execution: {}",
+          durationMilliseconds);
+    } catch (Throwable t) {
+      LOG.error("Error while performing table count: {}", t);
+    }
+  }
+
+  /**
+   * Processes the table count by iterating over SCM tables and retrieving the
+   * counts of objects in each table. The counts are then stored in the Recon
+   * database.
+   *
+   * @throws IOException if an I/O error occurs during table count processing.
+   */
+  public void processTableCount() throws IOException {
+    // Acquire write lock
+    lock.writeLock().lock();
+    try {
+      // Initialize the object count map
+      Map<String, Long> objectCountMap = initializeCountMap();
+
+      // Iterate over SCM tables
+      for (String tableName : getTaskTables()) {
+        Table table = scmDBStore.getTable(tableName);
+
+        try (TableIterator keyIter = table.iterator()) {
+          // Retrieve the count of objects in the table
+          long count = Iterators.size(keyIter);
+          objectCountMap.put(getRowKeyFromTable(tableName), count);
+        } catch (IOException ioEx) {
+          LOG.error("Unable to populate SCM Table Count in Recon DB.", ioEx);
+        }
+      }
+
+      // Write the counts to the Recon db if the object count map is not empty
+      if (!objectCountMap.isEmpty()) {
+        writeCountsToDB(objectCountMap);
+      }
+
+      objectCountMap.clear();
+      LOG.info("Completed writing SCM table counts to DB.");
+    } finally {
+      // Release write lock
+      lock.writeLock().unlock();
+    }
+  }
+
+
+  /**
+   * Writes the object counts from the object count map to the Recon database.
+   *
+   * @param objectCountMap a map containing table names as keys and their 
object
+   *                       counts as values.
+   */
+  private void writeCountsToDB(Map<String, Long> objectCountMap) {
+    List<ScmTableCount> insertToDb = new ArrayList<>();
+
+    // Iterate over the object count map
+    for (Map.Entry<String, Long> entry : objectCountMap.entrySet()) {
+      // Create a new ScmTableCount object
+      ScmTableCount scmTableCountRecord = new ScmTableCount();
+      scmTableCountRecord.setTableName(entry.getKey());
+      scmTableCountRecord.setCount(entry.getValue());
+
+      // Add the ScmTableCount object to the list
+      insertToDb.add(scmTableCountRecord);
+    }
+    // Insert the list of ScmTableCount objects into the Recon database
+    scmTableCountDao.insert(insertToDb);
+  }
+
+  private Map<String, Long> initializeCountMap() throws IOException {
+    Collection<String> tables = getTaskTables();
+    Map<String, Long> objectCountMap = new HashMap<>(tables.size());
+    for (String tableName: tables) {
+      String key = getRowKeyFromTable(tableName);
+      objectCountMap.put(key, 0L);
+    }
+    return objectCountMap;
+  }
+
+
+  /**
+   * Returns the list of SCM tables to be processed by the task.
+   *
+   * @return the list of SCM tables to be processed by the task.
+   * @throws IOException if an I/O error occurs.
+   */
+  public Collection<String> getTaskTables() throws IOException {
+    Collection<String> tables = new ArrayList<>();

Review Comment:
   ```suggestion
       List<String> tables = new ArrayList<>();
   ```



##########
hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/tasks/ScmTableCountTask.java:
##########
@@ -0,0 +1,217 @@
+/*
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.ozone.recon.tasks;
+
+import com.google.common.collect.Iterators;
+import org.apache.hadoop.hdds.utils.db.DBStore;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.TableIterator;
+import org.apache.hadoop.ozone.recon.scm.ReconScmTask;
+import org.apache.hadoop.ozone.recon.scm.ReconStorageContainerManagerFacade;
+import org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition;
+import org.hadoop.ozone.recon.schema.tables.daos.ReconTaskStatusDao;
+import org.hadoop.ozone.recon.schema.tables.daos.ScmTableCountDao;
+import org.hadoop.ozone.recon.schema.tables.pojos.ScmTableCount;
+import org.jooq.DSLContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Iterator;
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static 
org.apache.hadoop.hdds.scm.metadata.SCMDBDefinition.DELETED_BLOCKS;
+import static 
org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition.SCM_TABLE_COUNT_TABLE_NAME;
+
+
+/**
+ * Any background task that tracks SCM's table counts.
+ */
+public class ScmTableCountTask extends ReconScmTask {
+
+  private static final Logger LOG =
+      LoggerFactory.getLogger(ScmTableCountTask.class);
+
+  private final DBStore scmDBStore;
+  private final ScmTableCountDao scmTableCountDao;
+  private final DSLContext dslContext;
+  private final long interval;
+  private ReadWriteLock lock = new ReentrantReadWriteLock(true);
+  private static final long NANOSECONDS_IN_MILLISECOND = 1_000_000;
+
+  public ScmTableCountTask(ReconStorageContainerManagerFacade reconSCM,
+                           ReconTaskStatusDao reconTaskStatusDao,
+                           ReconTaskConfig reconTaskConfig,
+                           ScmTableCountDao scmTableCountDao,
+                           UtilizationSchemaDefinition schemaDefinition) {
+    super(reconTaskStatusDao);
+    this.scmDBStore = reconSCM.getScmDBStore();
+    this.scmTableCountDao = scmTableCountDao;
+    this.dslContext = schemaDefinition.getDSLContext();
+    this.interval = reconTaskConfig.getScmTableCountTaskInterval().toMillis();
+  }
+
+  @Override
+  protected synchronized void run() {
+    try {
+      while (canRun()) {
+        wait(interval);
+        runTableCountProcess();
+      }
+    } catch (Throwable t) {
+      LOG.error("Error while running ScmTableCountTask: {}", t);
+      if (t instanceof InterruptedException) {
+        Thread.currentThread().interrupt();
+      }
+    }
+  }
+
+  private void runTableCountProcess() {
+    try {
+      long startTime, endTime, duration, durationMilliseconds;
+      try {
+        int execute = 
dslContext.truncate(SCM_TABLE_COUNT_TABLE_NAME).execute();
+        LOG.info("Deleted {} records from {}", execute,
+            SCM_TABLE_COUNT_TABLE_NAME);
+      } catch (Exception e) {
+        LOG.error("An error occurred while truncating the table {}: {}",
+            SCM_TABLE_COUNT_TABLE_NAME, e.getMessage(), e);
+        return;
+      }
+      startTime = System.nanoTime();
+      processTableCount();
+      endTime = System.nanoTime();
+      duration = endTime - startTime;
+      durationMilliseconds = duration / NANOSECONDS_IN_MILLISECOND;
+      LOG.info(
+          "Elapsed Time in milliseconds for processTableCount() execution: {}",
+          durationMilliseconds);
+    } catch (Throwable t) {

Review Comment:
   Here we are catching Throwable and moving ahead but in caller run() method 
we are interrupting thread which is contradicting. Instead we should catch 
Exception and proceed.



##########
hadoop-ozone/recon/src/main/java/org/apache/hadoop/ozone/recon/tasks/ScmTableCountTask.java:
##########
@@ -0,0 +1,217 @@
+/*
+ * 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
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * 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.ozone.recon.tasks;
+
+import com.google.common.collect.Iterators;
+import org.apache.hadoop.hdds.utils.db.DBStore;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.apache.hadoop.hdds.utils.db.TableIterator;
+import org.apache.hadoop.ozone.recon.scm.ReconScmTask;
+import org.apache.hadoop.ozone.recon.scm.ReconStorageContainerManagerFacade;
+import org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition;
+import org.hadoop.ozone.recon.schema.tables.daos.ReconTaskStatusDao;
+import org.hadoop.ozone.recon.schema.tables.daos.ScmTableCountDao;
+import org.hadoop.ozone.recon.schema.tables.pojos.ScmTableCount;
+import org.jooq.DSLContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+
+import java.util.HashMap;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Iterator;
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
+import static 
org.apache.hadoop.hdds.scm.metadata.SCMDBDefinition.DELETED_BLOCKS;
+import static 
org.hadoop.ozone.recon.schema.UtilizationSchemaDefinition.SCM_TABLE_COUNT_TABLE_NAME;
+
+
+/**
+ * Any background task that tracks SCM's table counts.
+ */
+public class ScmTableCountTask extends ReconScmTask {
+
+  private static final Logger LOG =
+      LoggerFactory.getLogger(ScmTableCountTask.class);
+
+  private final DBStore scmDBStore;
+  private final ScmTableCountDao scmTableCountDao;
+  private final DSLContext dslContext;
+  private final long interval;
+  private ReadWriteLock lock = new ReentrantReadWriteLock(true);
+  private static final long NANOSECONDS_IN_MILLISECOND = 1_000_000;
+
+  public ScmTableCountTask(ReconStorageContainerManagerFacade reconSCM,
+                           ReconTaskStatusDao reconTaskStatusDao,
+                           ReconTaskConfig reconTaskConfig,
+                           ScmTableCountDao scmTableCountDao,
+                           UtilizationSchemaDefinition schemaDefinition) {
+    super(reconTaskStatusDao);
+    this.scmDBStore = reconSCM.getScmDBStore();
+    this.scmTableCountDao = scmTableCountDao;
+    this.dslContext = schemaDefinition.getDSLContext();
+    this.interval = reconTaskConfig.getScmTableCountTaskInterval().toMillis();
+  }
+
+  @Override
+  protected synchronized void run() {
+    try {
+      while (canRun()) {
+        wait(interval);
+        runTableCountProcess();
+      }
+    } catch (Throwable t) {
+      LOG.error("Error while running ScmTableCountTask: {}", t);
+      if (t instanceof InterruptedException) {
+        Thread.currentThread().interrupt();
+      }
+    }
+  }
+
+  private void runTableCountProcess() {
+    try {
+      long startTime, endTime, duration, durationMilliseconds;
+      try {
+        int execute = 
dslContext.truncate(SCM_TABLE_COUNT_TABLE_NAME).execute();
+        LOG.info("Deleted {} records from {}", execute,
+            SCM_TABLE_COUNT_TABLE_NAME);
+      } catch (Exception e) {
+        LOG.error("An error occurred while truncating the table {}: {}",
+            SCM_TABLE_COUNT_TABLE_NAME, e.getMessage(), e);
+        return;
+      }
+      startTime = System.nanoTime();
+      processTableCount();
+      endTime = System.nanoTime();
+      duration = endTime - startTime;
+      durationMilliseconds = duration / NANOSECONDS_IN_MILLISECOND;
+      LOG.info(
+          "Elapsed Time in milliseconds for processTableCount() execution: {}",
+          durationMilliseconds);
+    } catch (Throwable t) {
+      LOG.error("Error while performing table count: {}", t);
+    }
+  }
+
+  /**
+   * Processes the table count by iterating over SCM tables and retrieving the
+   * counts of objects in each table. The counts are then stored in the Recon
+   * database.
+   *
+   * @throws IOException if an I/O error occurs during table count processing.
+   */
+  public void processTableCount() throws IOException {
+    // Acquire write lock
+    lock.writeLock().lock();
+    try {
+      // Initialize the object count map
+      Map<String, Long> objectCountMap = initializeCountMap();
+
+      // Iterate over SCM tables
+      for (String tableName : getTaskTables()) {
+        Table table = scmDBStore.getTable(tableName);
+
+        try (TableIterator keyIter = table.iterator()) {
+          // Retrieve the count of objects in the table
+          long count = Iterators.size(keyIter);
+          objectCountMap.put(getRowKeyFromTable(tableName), count);
+        } catch (IOException ioEx) {
+          LOG.error("Unable to populate SCM Table Count in Recon DB.", ioEx);
+        }
+      }
+
+      // Write the counts to the Recon db if the object count map is not empty
+      if (!objectCountMap.isEmpty()) {
+        writeCountsToDB(objectCountMap);
+      }
+
+      objectCountMap.clear();
+      LOG.info("Completed writing SCM table counts to DB.");
+    } finally {
+      // Release write lock
+      lock.writeLock().unlock();
+    }
+  }
+
+
+  /**
+   * Writes the object counts from the object count map to the Recon database.
+   *
+   * @param objectCountMap a map containing table names as keys and their 
object
+   *                       counts as values.
+   */
+  private void writeCountsToDB(Map<String, Long> objectCountMap) {
+    List<ScmTableCount> insertToDb = new ArrayList<>();
+
+    // Iterate over the object count map
+    for (Map.Entry<String, Long> entry : objectCountMap.entrySet()) {
+      // Create a new ScmTableCount object
+      ScmTableCount scmTableCountRecord = new ScmTableCount();
+      scmTableCountRecord.setTableName(entry.getKey());
+      scmTableCountRecord.setCount(entry.getValue());
+
+      // Add the ScmTableCount object to the list
+      insertToDb.add(scmTableCountRecord);
+    }
+    // Insert the list of ScmTableCount objects into the Recon database
+    scmTableCountDao.insert(insertToDb);
+  }
+
+  private Map<String, Long> initializeCountMap() throws IOException {
+    Collection<String> tables = getTaskTables();

Review Comment:
   ```suggestion
       List<String> tables = getTaskTables();
   ```



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