phoenix-core/src/main/java/org/apache/phoenix/hbase/index/write/ParallelWriterIndexCommitter.java

/*
 * 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.phoenix.hbase.index.write;

import java.io.IOException;
import java.util.Collection;
import java.util.List;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Abortable;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.Stoppable;
import org.apache.hadoop.hbase.client.HTableInterface;
import org.apache.hadoop.hbase.client.Mutation;
import org.apache.hadoop.hbase.coprocessor.RegionCoprocessorEnvironment;
import org.apache.hadoop.hbase.regionserver.Region;
import org.apache.phoenix.hbase.index.exception.SingleIndexWriteFailureException;
import org.apache.phoenix.hbase.index.parallel.EarlyExitFailure;
import org.apache.phoenix.hbase.index.parallel.QuickFailingTaskRunner;
import org.apache.phoenix.hbase.index.parallel.Task;
import org.apache.phoenix.hbase.index.parallel.TaskBatch;
import org.apache.phoenix.hbase.index.parallel.ThreadPoolBuilder;
import org.apache.phoenix.hbase.index.parallel.ThreadPoolManager;
import org.apache.phoenix.hbase.index.table.CachingHTableFactory;
import org.apache.phoenix.hbase.index.table.HTableFactory;
import org.apache.phoenix.hbase.index.table.HTableInterfaceReference;
import org.apache.phoenix.hbase.index.util.KeyValueBuilder;
import org.apache.phoenix.util.IndexUtil;
import org.apache.phoenix.util.MetaDataUtil;

import com.google.common.collect.Multimap;

/**
 * Write index updates to the index tables in parallel. We attempt to early exit from the writes if any of the index
 * updates fails. Completion is determined by the following criteria: *
 * <ol>
 * <li>All index writes have returned, OR</li>
 * <li>Any single index write has failed</li>
 * </ol>
 * We attempt to quickly determine if any write has failed and not write to the remaining indexes to ensure a timely
 * recovery of the failed index writes.
 */
public class ParallelWriterIndexCommitter implements IndexCommitter {

    public static final String NUM_CONCURRENT_INDEX_WRITER_THREADS_CONF_KEY = "index.writer.threads.max";
    private static final int DEFAULT_CONCURRENT_INDEX_WRITER_THREADS = 10;
    private static final String INDEX_WRITER_KEEP_ALIVE_TIME_CONF_KEY = "index.writer.threads.keepalivetime";
    private static final Log LOG = LogFactory.getLog(ParallelWriterIndexCommitter.class);

    private HTableFactory factory;
    private Stoppable stopped;
    private QuickFailingTaskRunner pool;
    private KeyValueBuilder kvBuilder;
    private RegionCoprocessorEnvironment env;

    public ParallelWriterIndexCommitter() {}

    // For testing
    public ParallelWriterIndexCommitter(String hbaseVersion) {
        kvBuilder = KeyValueBuilder.get(hbaseVersion);
    }

    @Override
    public void setup(IndexWriter parent, RegionCoprocessorEnvironment env, String name) {
        this.env = env;
        Configuration conf = env.getConfiguration();
        setup(IndexWriterUtils.getDefaultDelegateHTableFactory(env),
                ThreadPoolManager.getExecutor(
                        new ThreadPoolBuilder(name, conf).setMaxThread(NUM_CONCURRENT_INDEX_WRITER_THREADS_CONF_KEY,
                                DEFAULT_CONCURRENT_INDEX_WRITER_THREADS).setCoreTimeout(
                                INDEX_WRITER_KEEP_ALIVE_TIME_CONF_KEY), env), env.getRegionServerServices(), parent,
                CachingHTableFactory.getCacheSize(conf));
        this.kvBuilder = KeyValueBuilder.get(env.getHBaseVersion());
    }

    /**
     * Setup <tt>this</tt>.
     * <p>
     * Exposed for TESTING
     */
    void setup(HTableFactory factory, ExecutorService pool, Abortable abortable, Stoppable stop, int cacheSize) {
        this.factory = new CachingHTableFactory(factory, cacheSize);
        this.pool = new QuickFailingTaskRunner(pool);
        this.stopped = stop;
    }

    @Override
    public void write(Multimap<HTableInterfaceReference, Mutation> toWrite) throws SingleIndexWriteFailureException {
        /*
         * This bit here is a little odd, so let's explain what's going on. Basically, we want to do the writes in
         * parallel to each index table, so each table gets its own task and is submitted to the pool. Where it gets
         * tricky is that we want to block the calling thread until one of two things happens: (1) all index tables get
         * successfully updated, or (2) any one of the index table writes fail; in either case, we should return as
         * quickly as possible. We get a little more complicated in that if we do get a single failure, but any of the
         * index writes hasn't been started yet (its been queued up, but not submitted to a thread) we want to that task
         * to fail immediately as we know that write is a waste and will need to be replayed anyways.
         */

        Set<Entry<HTableInterfaceReference, Collection<Mutation>>> entries = toWrite.asMap().entrySet();
        TaskBatch<Void> tasks = new TaskBatch<Void>(entries.size());
        for (Entry<HTableInterfaceReference, Collection<Mutation>> entry : entries) {
            // get the mutations for each table. We leak the implementation here a little bit to save
            // doing a complete copy over of all the index update for each table.
            final List<Mutation> mutations = kvBuilder.cloneIfNecessary((List<Mutation>)entry.getValue());
            final HTableInterfaceReference tableReference = entry.getKey();
            final RegionCoprocessorEnvironment env = this.env;
            /*
             * Write a batch of index updates to an index table. This operation stops (is cancelable) via two
             * mechanisms: (1) setting aborted or stopped on the IndexWriter or, (2) interrupting the running thread.
             * The former will only work if we are not in the midst of writing the current batch to the table, though we
             * do check these status variables before starting and before writing the batch. The latter usage,
             * interrupting the thread, will work in the previous situations as was at some points while writing the
             * batch, depending on the underlying writer implementation (HTableInterface#batch is blocking, but doesn't
             * elaborate when is supports an interrupt).
             */
            tasks.add(new Task<Void>() {

                /**
                 * Do the actual write to the primary table. We don't need to worry about closing the table because that
                 * is handled the {@link CachingHTableFactory}.
                 * 
                 * @return
                 */
                @SuppressWarnings("deprecation")
                @Override
                public Void call() throws Exception {
                    // this may have been queued, so another task infront of us may have failed, so we should
                    // early exit, if that's the case
                    throwFailureIfDone();

                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Writing index update:" + mutations + " to table: " + tableReference);
                    }
                    try {
                        // TODO: Once HBASE-11766 is fixed, reexamine whether this is necessary.
                        // Also, checking the prefix of the table name to determine if this is a local
                        // index is pretty hacky. If we're going to keep this, we should revisit that
                        // as well.
                        try {
                            if (tableReference.getTableName().startsWith(MetaDataUtil.LOCAL_INDEX_TABLE_PREFIX)) {
                                Region indexRegion = IndexUtil.getIndexRegion(env);
                                if (indexRegion != null) {
                                    throwFailureIfDone();
                                    indexRegion.batchMutate(mutations.toArray(new Mutation[mutations.size()]),
                                        HConstants.NO_NONCE, HConstants.NO_NONCE);
                                    return null;
                                }
                            }
                        } catch (IOException ignord) {
                            // when it's failed we fall back to the standard & slow way
                            if (LOG.isDebugEnabled()) {
                                LOG.debug("indexRegion.batchMutate failed and fall back to HTable.batch(). Got error="
                                        + ignord);
                            }
                        }
                        HTableInterface table = factory.getTable(tableReference.get());
                        throwFailureIfDone();
                        table.batch(mutations);
                    } catch (SingleIndexWriteFailureException e) {
                        throw e;
                    } catch (IOException e) {
                        throw new SingleIndexWriteFailureException(tableReference.toString(), mutations, e);
                    } catch (InterruptedException e) {
                        // reset the interrupt status on the thread
                        Thread.currentThread().interrupt();
                        throw new SingleIndexWriteFailureException(tableReference.toString(), mutations, e);
                    }
                    return null;
                }

                private void throwFailureIfDone() throws SingleIndexWriteFailureException {
                    if (this.isBatchFailed() || Thread.currentThread().isInterrupted()) { throw new SingleIndexWriteFailureException(
                            "Pool closed, not attempting to write to the index!", null); }

                }
            });
        }

        // actually submit the tasks to the pool and wait for them to finish/fail
        try {
            pool.submitUninterruptible(tasks);
        } catch (EarlyExitFailure e) {
            propagateFailure(e);
        } catch (ExecutionException e) {
            LOG.error("Found a failed index update!");
            propagateFailure(e.getCause());
        }

    }

    private void propagateFailure(Throwable throwable) throws SingleIndexWriteFailureException {
        try {
            throw throwable;
        } catch (SingleIndexWriteFailureException e1) {
            throw e1;
        } catch (Throwable e1) {
            throw new SingleIndexWriteFailureException("Got an abort notification while writing to the index!", e1);
        }

    }

    /**
     * {@inheritDoc}
     * <p>
     * This method should only be called <b>once</b>. Stopped state ({@link #isStopped()}) is managed by the external
     * {@link Stoppable}. This call does not delegate the stop down to the {@link Stoppable} passed in the constructor.
     * 
     * @param why
     *            the reason for stopping
     */
    @Override
    public void stop(String why) {
        LOG.info("Shutting down " + this.getClass().getSimpleName() + " because " + why);
        this.pool.stop(why);
        this.factory.shutdown();
    }

    @Override
    public boolean isStopped() {
        return this.stopped.isStopped();
    }
}