com.alibaba.wasp.fserver.SplitThread.java Source code

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/**
 * Copyright 2010 The Apache Software Foundation
 *
 * 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 com.alibaba.wasp.fserver;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;

import java.util.Iterator;
import java.util.concurrent.*;

/**
 * Compact entityGroup on request and then run split if appropriate
 */
public class SplitThread {
    static final Log LOG = LogFactory.getLog(SplitThread.class);

    private final FServer server;
    private final Configuration conf;

    private final ThreadPoolExecutor splits;

    /**
     * Splitting should not take place if the total number of entityGroups exceed
     * this. This is not a hard limit to the number of entityGroups but it is a
     * guideline to stop splitting after number of online entityGroups is greater
     * than this.
     */
    private int entityGroupSplitLimit;

    /** @param server */
    SplitThread(FServer server) {
        super();
        this.server = server;
        this.conf = server.getConfiguration();
        this.entityGroupSplitLimit = conf.getInt("wasp.fserver.entityGroupSplitLimit", Integer.MAX_VALUE);

        int splitThreads = conf.getInt("wasp.fserver.thread.split", 1);

        final String n = Thread.currentThread().getName();

        this.splits = (ThreadPoolExecutor) Executors.newFixedThreadPool(splitThreads, new ThreadFactory() {
            @Override
            public Thread newThread(Runnable r) {
                Thread t = new Thread(r);
                t.setName(n + "-splits-" + System.currentTimeMillis());
                return t;
            }
        });
    }

    @Override
    public String toString() {
        return "split_queue=" + splits.getQueue().size();
    }

    public String dumpQueue() {
        StringBuffer queueLists = new StringBuffer();
        queueLists.append("Split Queue dump:\n");
        queueLists.append("  Split Queue:\n");
        BlockingQueue<Runnable> lq = splits.getQueue();
        Iterator<Runnable> it = lq.iterator();
        while (it.hasNext()) {
            queueLists.append("    " + it.next().toString());
            queueLists.append("\n");
        }

        return queueLists.toString();
    }

    public synchronized void requestSplit(final EntityGroup eg, byte[] midKey) {
        if (midKey == null) {
            LOG.debug("entityGroup " + eg.getEntityGroupNameAsString() + " not splittable because midkey=null");
            return;
        }
        try {
            this.splits.execute(new SplitRequest(eg, midKey, this.server));
            if (LOG.isDebugEnabled()) {
                LOG.debug("Split requested for " + eg + ".  " + this);
            }
        } catch (RejectedExecutionException ree) {
            LOG.info("Could not execute split for " + eg, ree);
        }
    }

    /**
     * Only interrupt once it's done with a run through the work loop.
     */
    void interruptIfNecessary() {
        splits.shutdown();
    }

    private void waitFor(ThreadPoolExecutor t, String name) {
        boolean done = false;
        while (!done) {
            try {
                done = t.awaitTermination(60, TimeUnit.SECONDS);
                LOG.debug("Waiting for " + name + " to finish...");
            } catch (InterruptedException ie) {
                LOG.debug("Interrupted waiting for " + name + " to finish...");
            }
        }
    }

    void join() {
        waitFor(splits, "Split Thread");
    }

    /**
     * @return the entityGroupSplitLimit
     */
    public int getEntityGroupSplitLimit() {
        return this.entityGroupSplitLimit;
    }
}