org.apache.hadoop.hbase.util.MultiHConnection.java Source code

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/**
 *
 * 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.hbase.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.Connection;
import org.apache.hadoop.hbase.client.ConnectionFactory;
import org.apache.hadoop.hbase.client.HConnection;
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 final Object hConnectionsLock = new Object();
    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;
        synchronized (this.hConnectionsLock) {
            hConnections = new HConnection[noOfConnections];
            for (int i = 0; i < noOfConnections; i++) {
                HConnection conn = (HConnection) ConnectionFactory.createConnection(conf);
                hConnections[i] = conn;
            }
        }
        createBatchPool(conf);
    }

    /**
     * Close the open connections and shutdown the batchpool
     */
    public void close() {
        synchronized (hConnectionsLock) {
            if (hConnections != null) {
                for (Connection 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
     */
    @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 ConnectionImplementation.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 ConnectionImplementation.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;
    }

}