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

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Here is the source code for org.apache.hadoop.hbase.util.FSRegionScanner.java

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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.util.HashMap;
import java.util.Map;

import java.util.concurrent.atomic.AtomicInteger;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.fs.BlockLocation;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HConstants;

/**
 * Thread that walks over the filesystem, and computes the mappings
 * <Region -> BestHost> and <Region -> Map<HostName, fractional-locality-of-region>>
 *
 */
@InterfaceAudience.Private
class FSRegionScanner implements Runnable {
    static private final Log LOG = LogFactory.getLog(FSRegionScanner.class);

    private Path regionPath;

    /**
     * The file system used
     */
    private FileSystem fs;

    /**
     * Maps each region to the RS with highest locality for that region.
     */
    private Map<String, String> regionToBestLocalityRSMapping;

    /**
     * Maps region encoded names to maps of hostnames to fractional locality of
     * that region on that host.
     */
    private Map<String, Map<String, Float>> regionDegreeLocalityMapping;

    FSRegionScanner(FileSystem fs, Path regionPath, Map<String, String> regionToBestLocalityRSMapping,
            Map<String, Map<String, Float>> regionDegreeLocalityMapping) {
        this.fs = fs;
        this.regionPath = regionPath;
        this.regionToBestLocalityRSMapping = regionToBestLocalityRSMapping;
        this.regionDegreeLocalityMapping = regionDegreeLocalityMapping;
    }

    @Override
    public void run() {
        try {
            // empty the map for each region
            Map<String, AtomicInteger> blockCountMap = new HashMap<String, AtomicInteger>();

            //get table name
            String tableName = regionPath.getParent().getName();
            int totalBlkCount = 0;

            // ignore null
            FileStatus[] cfList = fs.listStatus(regionPath);
            if (null == cfList) {
                return;
            }

            // for each cf, get all the blocks information
            for (FileStatus cfStatus : cfList) {
                if (!cfStatus.isDirectory()) {
                    // skip because this is not a CF directory
                    continue;
                }
                if (cfStatus.getPath().getName().startsWith(".")
                        || HConstants.HBASE_NON_USER_TABLE_DIRS.contains(cfStatus.getPath().getName())) {
                    continue;
                }
                FileStatus[] storeFileLists = fs.listStatus(cfStatus.getPath());
                if (null == storeFileLists) {
                    continue;
                }

                for (FileStatus storeFile : storeFileLists) {
                    BlockLocation[] blkLocations = fs.getFileBlockLocations(storeFile, 0, storeFile.getLen());
                    if (null == blkLocations) {
                        continue;
                    }

                    totalBlkCount += blkLocations.length;
                    for (BlockLocation blk : blkLocations) {
                        for (String host : blk.getHosts()) {
                            AtomicInteger count = blockCountMap.get(host);
                            if (count == null) {
                                count = new AtomicInteger(0);
                                blockCountMap.put(host, count);
                            }
                            count.incrementAndGet();
                        }
                    }
                }
            }

            if (regionToBestLocalityRSMapping != null) {
                int largestBlkCount = 0;
                String hostToRun = null;
                for (Map.Entry<String, AtomicInteger> entry : blockCountMap.entrySet()) {
                    String host = entry.getKey();

                    int tmp = entry.getValue().get();
                    if (tmp > largestBlkCount) {
                        largestBlkCount = tmp;
                        hostToRun = host;
                    }
                }

                // empty regions could make this null
                if (null == hostToRun) {
                    return;
                }

                if (hostToRun.endsWith(".")) {
                    hostToRun = hostToRun.substring(0, hostToRun.length() - 1);
                }
                String name = tableName + ":" + regionPath.getName();
                synchronized (regionToBestLocalityRSMapping) {
                    regionToBestLocalityRSMapping.put(name, hostToRun);
                }
            }

            if (regionDegreeLocalityMapping != null && totalBlkCount > 0) {
                Map<String, Float> hostLocalityMap = new HashMap<String, Float>();
                for (Map.Entry<String, AtomicInteger> entry : blockCountMap.entrySet()) {
                    String host = entry.getKey();
                    if (host.endsWith(".")) {
                        host = host.substring(0, host.length() - 1);
                    }
                    // Locality is fraction of blocks local to this host.
                    float locality = ((float) entry.getValue().get()) / totalBlkCount;
                    hostLocalityMap.put(host, locality);
                }
                // Put the locality map into the result map, keyed by the encoded name
                // of the region.
                regionDegreeLocalityMapping.put(regionPath.getName(), hostLocalityMap);
            }
        } catch (IOException e) {
            LOG.warn("Problem scanning file system", e);
        } catch (RuntimeException e) {
            LOG.warn("Problem scanning file system", e);
        }
    }
}