[GitHub] [incubator-pinot] Jackie-Jiang commented on a change in pull request #6346: Introduce DimensionTableDataManager

[GitBox <gi...@apache.org>]

Jackie-Jiang commented on a change in pull request #6346:
URL: https://github.com/apache/incubator-pinot/pull/6346#discussion_r542962860



##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {

Review comment:
       For clarity
   ```suggestion
     public static DimensionTableDataManager createInstanceByTableName(String tableNameWithType) {
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {

Review comment:
       For clarity
   ```suggestion
     public static DimensionTableDataManager getInstanceByTableName(String tableNameWithType) {
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {
+    return _instances.get(tableName);
+  }
+
+  /*
+   * DimensionTableDataManager Instance Properties/Methods
+   */
+
+  private final ReadWriteLock _rwl = new ReentrantReadWriteLock();
+  private final Lock _lookupTableReadLock = _rwl.readLock();
+  private final Lock _lookupTableWriteLock = _rwl.writeLock();
+
+  // _lookupTable is a HashMap used for storing/serving records for a table keyed by table PK
+  @GuardedBy("_rwl")
+  private final Map<PrimaryKey, GenericRow> _lookupTable = new HashMap<>();
+  private Schema _tableSchema;
+  private List<String> _primaryKeyColumns;
+
+  @Override
+  protected void doInit() {
+    super.doInit();
+
+    _tableSchema = ZKMetadataProvider.getTableSchema(_propertyStore, _tableNameWithType);
+    Preconditions.checkState(_tableSchema != null, "Failed to find schema for table: %s", _tableNameWithType);
+    _primaryKeyColumns = _tableSchema.getPrimaryKeyColumns();
+    Preconditions.checkState(!CollectionUtils.isEmpty(_primaryKeyColumns),
+        "Primary key columns must be configured for dimension table: %s", _tableNameWithType);
+  }
+
+  @Override
+  public void addSegment(File indexDir, IndexLoadingConfig indexLoadingConfig)
+      throws Exception {
+    super.addSegment(indexDir, indexLoadingConfig);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully loaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      throw new RuntimeException(
+          String.format("Error loading lookup table: %s", getTableName()),e);
+    }
+  }
+
+  @Override
+  public void removeSegment(String segmentName) {
+    super.removeSegment(segmentName);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully removed segment and reloaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      _logger.error("Error reloading lookup table after segment remove for table {}", getTableName());
+    }
+  }
+
+  /*
+   * `loadLookupTable()` reads contents of the DimensionTable into _lookupTable HashMap for fast lookup.
+   */
+  private void loadLookupTable() throws Exception {
+    _lookupTableWriteLock.lock();
+    try {
+      List<SegmentDataManager> segmentManagers = acquireAllSegments();
+      if (segmentManagers.size() == 0) {
+        _lookupTable.clear();
+        return;
+      }
+
+      List<File> indexDirs = new ArrayList<>();
+      for (SegmentDataManager segmentManager: segmentManagers) {
+        IndexSegment indexSegment = segmentManager.getSegment();
+        System.out.println(indexSegment.getSegmentName());
+        indexDirs.add(indexSegment.getSegmentMetadata().getIndexDir());
+      }
+      MultiplePinotSegmentRecordReader reader = new MultiplePinotSegmentRecordReader(indexDirs);

Review comment:
       No need to use `MultiplePinotSegmentRecordReader` here, use `PinotSegmentRecordReader` instead on each segment. Use try-with-resource to close the reader after the reading

##########
File path: pinot-core/src/test/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManagerTest.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.yammer.metrics.core.MetricsRegistry;
+import java.io.File;
+import java.net.URL;
+import java.util.List;
+import org.apache.commons.io.FileUtils;
+import org.apache.helix.AccessOption;
+import org.apache.helix.HelixManager;
+import org.apache.helix.ZNRecord;
+import org.apache.helix.store.zk.ZkHelixPropertyStore;
+import org.apache.pinot.common.metrics.ServerMetrics;
+import org.apache.pinot.common.segment.ReadMode;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.manager.config.TableDataManagerConfig;
+import org.apache.pinot.core.indexsegment.generator.SegmentGeneratorConfig;
+import org.apache.pinot.core.indexsegment.generator.SegmentVersion;
+import org.apache.pinot.core.segment.creator.SegmentIndexCreationDriver;
+import org.apache.pinot.core.segment.creator.impl.SegmentCreationDriverFactory;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.core.segment.index.loader.LoaderTest;
+import org.apache.pinot.segments.v1.creator.SegmentTestUtils;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+import org.testng.Assert;
+import org.testng.annotations.AfterSuite;
+import org.testng.annotations.BeforeSuite;
+import org.testng.annotations.Test;
+
+import static org.mockito.Mockito.*;
+
+
+public class DimensionTableDataManagerTest {
+  private static final String TABLE_NAME = "dimBaseballTeams";
+  private static final File INDEX_DIR = new File(LoaderTest.class.getName());
+  private static final String AVRO_DATA_PATH = "data/dimBaseballTeams.avro";
+
+  private File _indexDir;
+  private IndexLoadingConfig _indexLoadingConfig;
+
+  @BeforeSuite
+  public void setUp()
+      throws Exception {
+    // prepare segment data
+    URL resourceUrl = getClass().getClassLoader().getResource(AVRO_DATA_PATH);
+    Assert.assertNotNull(resourceUrl);
+    File avroFile = new File(resourceUrl.getFile());
+
+    // create segment
+    SegmentGeneratorConfig segmentGeneratorConfig =
+        SegmentTestUtils.getSegmentGeneratorConfigWithoutTimeColumn(avroFile, INDEX_DIR, TABLE_NAME);
+    segmentGeneratorConfig.setSegmentVersion(SegmentVersion.v3);
+    SegmentIndexCreationDriver driver = SegmentCreationDriverFactory.get(null);
+    driver.init(segmentGeneratorConfig);
+    driver.build();
+    _indexDir = new File(INDEX_DIR, driver.getSegmentName());
+
+    _indexLoadingConfig = new IndexLoadingConfig();
+    _indexLoadingConfig.setReadMode(ReadMode.mmap);
+    _indexLoadingConfig.setSegmentVersion(SegmentVersion.v3);
+  }
+
+  @AfterSuite

Review comment:
       ```suggestion
     @AfterClass
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {
+    return _instances.get(tableName);
+  }
+
+  /*
+   * DimensionTableDataManager Instance Properties/Methods
+   */
+
+  private final ReadWriteLock _rwl = new ReentrantReadWriteLock();
+  private final Lock _lookupTableReadLock = _rwl.readLock();
+  private final Lock _lookupTableWriteLock = _rwl.writeLock();
+
+  // _lookupTable is a HashMap used for storing/serving records for a table keyed by table PK
+  @GuardedBy("_rwl")
+  private final Map<PrimaryKey, GenericRow> _lookupTable = new HashMap<>();
+  private Schema _tableSchema;
+  private List<String> _primaryKeyColumns;
+
+  @Override
+  protected void doInit() {
+    super.doInit();
+
+    _tableSchema = ZKMetadataProvider.getTableSchema(_propertyStore, _tableNameWithType);
+    Preconditions.checkState(_tableSchema != null, "Failed to find schema for table: %s", _tableNameWithType);
+    _primaryKeyColumns = _tableSchema.getPrimaryKeyColumns();
+    Preconditions.checkState(!CollectionUtils.isEmpty(_primaryKeyColumns),
+        "Primary key columns must be configured for dimension table: %s", _tableNameWithType);
+  }
+
+  @Override
+  public void addSegment(File indexDir, IndexLoadingConfig indexLoadingConfig)
+      throws Exception {
+    super.addSegment(indexDir, indexLoadingConfig);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully loaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      throw new RuntimeException(
+          String.format("Error loading lookup table: %s", getTableName()),e);

Review comment:
       (nit) reformat

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {
+    return _instances.get(tableName);
+  }
+
+  /*
+   * DimensionTableDataManager Instance Properties/Methods
+   */
+
+  private final ReadWriteLock _rwl = new ReentrantReadWriteLock();
+  private final Lock _lookupTableReadLock = _rwl.readLock();
+  private final Lock _lookupTableWriteLock = _rwl.writeLock();
+
+  // _lookupTable is a HashMap used for storing/serving records for a table keyed by table PK
+  @GuardedBy("_rwl")
+  private final Map<PrimaryKey, GenericRow> _lookupTable = new HashMap<>();
+  private Schema _tableSchema;
+  private List<String> _primaryKeyColumns;
+
+  @Override
+  protected void doInit() {
+    super.doInit();
+
+    _tableSchema = ZKMetadataProvider.getTableSchema(_propertyStore, _tableNameWithType);
+    Preconditions.checkState(_tableSchema != null, "Failed to find schema for table: %s", _tableNameWithType);
+    _primaryKeyColumns = _tableSchema.getPrimaryKeyColumns();
+    Preconditions.checkState(!CollectionUtils.isEmpty(_primaryKeyColumns),
+        "Primary key columns must be configured for dimension table: %s", _tableNameWithType);
+  }
+
+  @Override
+  public void addSegment(File indexDir, IndexLoadingConfig indexLoadingConfig)
+      throws Exception {
+    super.addSegment(indexDir, indexLoadingConfig);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully loaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      throw new RuntimeException(
+          String.format("Error loading lookup table: %s", getTableName()),e);
+    }
+  }
+
+  @Override
+  public void removeSegment(String segmentName) {
+    super.removeSegment(segmentName);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully removed segment and reloaded lookup table for {}", getTableName());

Review comment:
       (nit)
   ```suggestion
         _logger.info("Successfully removed segment and reloaded lookup table: {}", getTableName());
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);

Review comment:
       Always create a new one instead of reusing the existing one (there should be no existing one normally)
   ```suggestion
       DimensionTableDataManager instance = new DimensionTableDataManager();
       _instances.put(tableNameWithType, instance);
       return instance;
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {
+    return _instances.get(tableName);
+  }
+
+  /*
+   * DimensionTableDataManager Instance Properties/Methods
+   */
+
+  private final ReadWriteLock _rwl = new ReentrantReadWriteLock();
+  private final Lock _lookupTableReadLock = _rwl.readLock();
+  private final Lock _lookupTableWriteLock = _rwl.writeLock();
+
+  // _lookupTable is a HashMap used for storing/serving records for a table keyed by table PK
+  @GuardedBy("_rwl")
+  private final Map<PrimaryKey, GenericRow> _lookupTable = new HashMap<>();
+  private Schema _tableSchema;
+  private List<String> _primaryKeyColumns;
+
+  @Override
+  protected void doInit() {
+    super.doInit();
+
+    _tableSchema = ZKMetadataProvider.getTableSchema(_propertyStore, _tableNameWithType);
+    Preconditions.checkState(_tableSchema != null, "Failed to find schema for table: %s", _tableNameWithType);
+    _primaryKeyColumns = _tableSchema.getPrimaryKeyColumns();
+    Preconditions.checkState(!CollectionUtils.isEmpty(_primaryKeyColumns),
+        "Primary key columns must be configured for dimension table: %s", _tableNameWithType);
+  }
+
+  @Override
+  public void addSegment(File indexDir, IndexLoadingConfig indexLoadingConfig)
+      throws Exception {
+    super.addSegment(indexDir, indexLoadingConfig);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully loaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      throw new RuntimeException(
+          String.format("Error loading lookup table: %s", getTableName()),e);
+    }
+  }
+
+  @Override
+  public void removeSegment(String segmentName) {
+    super.removeSegment(segmentName);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully removed segment and reloaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      _logger.error("Error reloading lookup table after segment remove for table {}", getTableName());
+    }
+  }
+
+  /*
+   * `loadLookupTable()` reads contents of the DimensionTable into _lookupTable HashMap for fast lookup.
+   */
+  private void loadLookupTable() throws Exception {
+    _lookupTableWriteLock.lock();
+    try {

Review comment:
       To simplify the logic, clear the lookup table first, then load it

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}

Review comment:
       (nit) 
   ```suggestion
     private DimensionTableDataManager() {
     }
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {
+    return _instances.get(tableName);
+  }
+
+  /*
+   * DimensionTableDataManager Instance Properties/Methods
+   */
+
+  private final ReadWriteLock _rwl = new ReentrantReadWriteLock();
+  private final Lock _lookupTableReadLock = _rwl.readLock();
+  private final Lock _lookupTableWriteLock = _rwl.writeLock();
+
+  // _lookupTable is a HashMap used for storing/serving records for a table keyed by table PK
+  @GuardedBy("_rwl")
+  private final Map<PrimaryKey, GenericRow> _lookupTable = new HashMap<>();
+  private Schema _tableSchema;
+  private List<String> _primaryKeyColumns;
+
+  @Override
+  protected void doInit() {
+    super.doInit();
+
+    _tableSchema = ZKMetadataProvider.getTableSchema(_propertyStore, _tableNameWithType);
+    Preconditions.checkState(_tableSchema != null, "Failed to find schema for table: %s", _tableNameWithType);
+    _primaryKeyColumns = _tableSchema.getPrimaryKeyColumns();
+    Preconditions.checkState(!CollectionUtils.isEmpty(_primaryKeyColumns),
+        "Primary key columns must be configured for dimension table: %s", _tableNameWithType);
+  }
+
+  @Override
+  public void addSegment(File indexDir, IndexLoadingConfig indexLoadingConfig)
+      throws Exception {
+    super.addSegment(indexDir, indexLoadingConfig);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully loaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      throw new RuntimeException(
+          String.format("Error loading lookup table: %s", getTableName()),e);
+    }
+  }
+
+  @Override
+  public void removeSegment(String segmentName) {
+    super.removeSegment(segmentName);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully removed segment and reloaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      _logger.error("Error reloading lookup table after segment remove for table {}", getTableName());

Review comment:
       Wrap it into a `RuntimeException` and throw it

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {
+    return _instances.get(tableName);
+  }
+
+  /*
+   * DimensionTableDataManager Instance Properties/Methods
+   */
+
+  private final ReadWriteLock _rwl = new ReentrantReadWriteLock();
+  private final Lock _lookupTableReadLock = _rwl.readLock();
+  private final Lock _lookupTableWriteLock = _rwl.writeLock();
+
+  // _lookupTable is a HashMap used for storing/serving records for a table keyed by table PK
+  @GuardedBy("_rwl")
+  private final Map<PrimaryKey, GenericRow> _lookupTable = new HashMap<>();
+  private Schema _tableSchema;
+  private List<String> _primaryKeyColumns;
+
+  @Override
+  protected void doInit() {
+    super.doInit();
+
+    _tableSchema = ZKMetadataProvider.getTableSchema(_propertyStore, _tableNameWithType);
+    Preconditions.checkState(_tableSchema != null, "Failed to find schema for table: %s", _tableNameWithType);
+    _primaryKeyColumns = _tableSchema.getPrimaryKeyColumns();
+    Preconditions.checkState(!CollectionUtils.isEmpty(_primaryKeyColumns),
+        "Primary key columns must be configured for dimension table: %s", _tableNameWithType);
+  }
+
+  @Override
+  public void addSegment(File indexDir, IndexLoadingConfig indexLoadingConfig)
+      throws Exception {
+    super.addSegment(indexDir, indexLoadingConfig);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully loaded lookup table for {}", getTableName());

Review comment:
       (nit)
   ```suggestion
         _logger.info("Successfully loaded lookup table: {}", getTableName());
   ```

##########
File path: pinot-core/src/test/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManagerTest.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.yammer.metrics.core.MetricsRegistry;
+import java.io.File;
+import java.net.URL;
+import java.util.List;
+import org.apache.commons.io.FileUtils;
+import org.apache.helix.AccessOption;
+import org.apache.helix.HelixManager;
+import org.apache.helix.ZNRecord;
+import org.apache.helix.store.zk.ZkHelixPropertyStore;
+import org.apache.pinot.common.metrics.ServerMetrics;
+import org.apache.pinot.common.segment.ReadMode;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.manager.config.TableDataManagerConfig;
+import org.apache.pinot.core.indexsegment.generator.SegmentGeneratorConfig;
+import org.apache.pinot.core.indexsegment.generator.SegmentVersion;
+import org.apache.pinot.core.segment.creator.SegmentIndexCreationDriver;
+import org.apache.pinot.core.segment.creator.impl.SegmentCreationDriverFactory;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.core.segment.index.loader.LoaderTest;
+import org.apache.pinot.segments.v1.creator.SegmentTestUtils;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+import org.testng.Assert;
+import org.testng.annotations.AfterSuite;
+import org.testng.annotations.BeforeSuite;
+import org.testng.annotations.Test;
+
+import static org.mockito.Mockito.*;
+
+
+public class DimensionTableDataManagerTest {
+  private static final String TABLE_NAME = "dimBaseballTeams";
+  private static final File INDEX_DIR = new File(LoaderTest.class.getName());
+  private static final String AVRO_DATA_PATH = "data/dimBaseballTeams.avro";
+
+  private File _indexDir;
+  private IndexLoadingConfig _indexLoadingConfig;
+
+  @BeforeSuite

Review comment:
       ```suggestion
     @BeforeClass
   ```

##########
File path: pinot-core/src/main/java/org/apache/pinot/core/data/manager/offline/DimensionTableDataManager.java
##########
@@ -0,0 +1,160 @@
+/**
+ * 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.pinot.core.data.manager.offline;
+
+import com.google.common.base.Preconditions;
+import java.io.File;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+import javax.annotation.concurrent.GuardedBy;
+import javax.annotation.concurrent.ThreadSafe;
+import org.apache.commons.collections.CollectionUtils;
+import org.apache.pinot.common.metadata.ZKMetadataProvider;
+import org.apache.pinot.core.data.manager.SegmentDataManager;
+import org.apache.pinot.core.data.readers.MultiplePinotSegmentRecordReader;
+import org.apache.pinot.core.indexsegment.IndexSegment;
+import org.apache.pinot.core.segment.index.loader.IndexLoadingConfig;
+import org.apache.pinot.spi.data.FieldSpec;
+import org.apache.pinot.spi.data.Schema;
+import org.apache.pinot.spi.data.readers.GenericRow;
+import org.apache.pinot.spi.data.readers.PrimaryKey;
+
+/**
+ * Dimension Table is a special type of OFFLINE table which is assigned to all servers
+ * in a tenant and is used to execute a LOOKUP Transform Function. DimensionTableDataManager
+ * loads the contents into a HashMap for faster access thus the size should be small
+ * enough to easily fit in memory.
+ *
+ * DimensionTableDataManager uses Registry of Singletons pattern to store one instance per table
+ * which can be accessed via `getInstanceByTableName` static method.
+ */
+@ThreadSafe
+public class DimensionTableDataManager extends OfflineTableDataManager {
+  // Storing singletons per table in a HashMap
+  private static final Map<String, DimensionTableDataManager> _instances = new ConcurrentHashMap<>();
+
+  private DimensionTableDataManager() {}
+
+  public static DimensionTableDataManager createInstanceByTableName(String tableName) {
+    _instances.putIfAbsent(tableName, new DimensionTableDataManager());
+    return _instances.get(tableName);
+  }
+
+  public static DimensionTableDataManager getInstanceByTableName(String tableName) {
+    return _instances.get(tableName);
+  }
+
+  /*
+   * DimensionTableDataManager Instance Properties/Methods
+   */
+
+  private final ReadWriteLock _rwl = new ReentrantReadWriteLock();
+  private final Lock _lookupTableReadLock = _rwl.readLock();
+  private final Lock _lookupTableWriteLock = _rwl.writeLock();
+
+  // _lookupTable is a HashMap used for storing/serving records for a table keyed by table PK
+  @GuardedBy("_rwl")
+  private final Map<PrimaryKey, GenericRow> _lookupTable = new HashMap<>();
+  private Schema _tableSchema;
+  private List<String> _primaryKeyColumns;
+
+  @Override
+  protected void doInit() {
+    super.doInit();
+
+    _tableSchema = ZKMetadataProvider.getTableSchema(_propertyStore, _tableNameWithType);
+    Preconditions.checkState(_tableSchema != null, "Failed to find schema for table: %s", _tableNameWithType);
+    _primaryKeyColumns = _tableSchema.getPrimaryKeyColumns();
+    Preconditions.checkState(!CollectionUtils.isEmpty(_primaryKeyColumns),
+        "Primary key columns must be configured for dimension table: %s", _tableNameWithType);
+  }
+
+  @Override
+  public void addSegment(File indexDir, IndexLoadingConfig indexLoadingConfig)
+      throws Exception {
+    super.addSegment(indexDir, indexLoadingConfig);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully loaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      throw new RuntimeException(
+          String.format("Error loading lookup table: %s", getTableName()),e);
+    }
+  }
+
+  @Override
+  public void removeSegment(String segmentName) {
+    super.removeSegment(segmentName);
+    try {
+      loadLookupTable();
+      _logger.info("Successfully removed segment and reloaded lookup table for {}", getTableName());
+    } catch (Exception e) {
+      _logger.error("Error reloading lookup table after segment remove for table {}", getTableName());
+    }
+  }
+
+  /*
+   * `loadLookupTable()` reads contents of the DimensionTable into _lookupTable HashMap for fast lookup.
+   */
+  private void loadLookupTable() throws Exception {
+    _lookupTableWriteLock.lock();
+    try {
+      List<SegmentDataManager> segmentManagers = acquireAllSegments();
+      if (segmentManagers.size() == 0) {
+        _lookupTable.clear();
+        return;
+      }
+
+      List<File> indexDirs = new ArrayList<>();
+      for (SegmentDataManager segmentManager: segmentManagers) {
+        IndexSegment indexSegment = segmentManager.getSegment();
+        System.out.println(indexSegment.getSegmentName());

Review comment:
       Remove




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