HBASE-11610 Enhance remote meta updates (Virag Kothari)

hbase-server/src/main/java/org/apache/hadoop/hbase/util/MultiHConnection.java

@@ -0,0 +1,156 @@
+/**
+ *
+ * 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.hbase.util;
+
+import java.io.IOException;
+import java.io.InterruptedIOException;
+import java.util.List;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.LinkedBlockingQueue;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.ThreadPoolExecutor;
+import java.util.concurrent.TimeUnit;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.HConnection;
+import org.apache.hadoop.hbase.client.HConnectionManager;
+import org.apache.hadoop.hbase.client.Row;
+import org.apache.hadoop.hbase.client.coprocessor.Batch;
+
+/**
+ * Provides ability to create multiple HConnection instances and allows to process a batch of
+ * actions using HConnection.processBatchCallback()
+ */
+@InterfaceAudience.Private
+public class MultiHConnection {
+  private static final Log LOG = LogFactory.getLog(MultiHConnection.class);
+  private HConnection[] hConnections;
+  private int noOfConnections;
+  private ExecutorService batchPool;
+
+  /**
+   * Create multiple HConnection instances and initialize a thread pool executor
+   * @param conf configuration
+   * @param noOfConnections total no of HConnections to create
+   * @throws IOException
+   */
+  public MultiHConnection(Configuration conf, int noOfConnections)
+      throws IOException {
+    this.noOfConnections = noOfConnections;
+    hConnections = new HConnection[noOfConnections];
+    for (int i = 0; i < noOfConnections; i++) {
+      HConnection conn = HConnectionManager.createConnection(conf);
+      hConnections[i] = conn;
+    }
+    createBatchPool(conf);
+  }
+
+  /**
+   * Close the open connections and shutdown the batchpool
+   */
+  public void close() {
+    if (hConnections != null) {
+      synchronized (hConnections) {
+        if (hConnections != null) {
+          for (HConnection conn : hConnections) {
+            if (conn != null) {
+              try {
+                conn.close();
+              } catch (IOException e) {
+                LOG.info("Got exception in closing connection", e);
+              } finally {
+                conn = null;
+              }
+            }
+          }
+          hConnections = null;
+        }
+      }
+    }
+    if (this.batchPool != null && !this.batchPool.isShutdown()) {
+      this.batchPool.shutdown();
+      try {
+        if (!this.batchPool.awaitTermination(10, TimeUnit.SECONDS)) {
+          this.batchPool.shutdownNow();
+        }
+      } catch (InterruptedException e) {
+        this.batchPool.shutdownNow();
+      }
+    }
+
+  }
+
+  /**
+   * Randomly pick a connection and process the batch of actions for a given table
+   * @param actions the actions
+   * @param tableName table name
+   * @param results the results array
+   * @param callback 
+   * @throws IOException
+   * @throws InterruptedException
+   */
+  @SuppressWarnings("deprecation")
+  public <R> void processBatchCallback(List<? extends Row> actions, TableName tableName,
+      Object[] results, Batch.Callback<R> callback) throws IOException {
+    // Currently used by RegionStateStore
+    // A deprecated method is used as multiple threads accessing RegionStateStore do a single put
+    // and htable is not thread safe. Alternative would be to create an Htable instance for each 
+    // put but that is not very efficient.
+    // See HBASE-11610 for more details.
+    try {
+      hConnections[ThreadLocalRandom.current().nextInt(noOfConnections)].processBatchCallback(
+        actions, tableName, this.batchPool, results, callback);
+    } catch (InterruptedException e) {
+      throw new InterruptedIOException(e.getMessage());
+    }
+  }
+
+  
+  // Copied from HConnectionImplementation.getBatchPool()
+  // We should get rid of this when HConnection.processBatchCallback is un-deprecated and provides
+  // an API to manage a batch pool
+  private void createBatchPool(Configuration conf) {
+    // Use the same config for keep alive as in HConnectionImplementation.getBatchPool();
+    int maxThreads = conf.getInt("hbase.multihconnection.threads.max", 256);
+    int coreThreads = conf.getInt("hbase.multihconnection.threads.core", 256);
+    if (maxThreads == 0) {
+      maxThreads = Runtime.getRuntime().availableProcessors() * 8;
+    }
+    if (coreThreads == 0) {
+      coreThreads = Runtime.getRuntime().availableProcessors() * 8;
+    }
+    long keepAliveTime = conf.getLong("hbase.multihconnection.threads.keepalivetime", 60);
+    LinkedBlockingQueue<Runnable> workQueue =
+        new LinkedBlockingQueue<Runnable>(maxThreads
+            * conf.getInt(HConstants.HBASE_CLIENT_MAX_TOTAL_TASKS,
+              HConstants.DEFAULT_HBASE_CLIENT_MAX_TOTAL_TASKS));
+    ThreadPoolExecutor tpe =
+        new ThreadPoolExecutor(coreThreads, maxThreads, keepAliveTime, TimeUnit.SECONDS, workQueue,
+            Threads.newDaemonThreadFactory("MultiHConnection" + "-shared-"));
+    tpe.allowCoreThreadTimeOut(true);
+    this.batchPool = tpe;
+  }
+  
+}