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Server functionality for HBase
/**
* 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.zookeeper;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.List;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.HConstants;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.hadoop.hbase.exceptions.DeserializationException;
import org.apache.hadoop.hbase.shaded.protobuf.generated.ClusterStatusProtos.RegionStoreSequenceIds;
import org.apache.zookeeper.KeeperException;
/**
* Common methods and attributes used by {@link org.apache.hadoop.hbase.master.SplitLogManager}
* and {@link org.apache.hadoop.hbase.regionserver.SplitLogWorker}
* running distributed splitting of WAL logs.
*/
@InterfaceAudience.Private
public class ZKSplitLog {
private static final Log LOG = LogFactory.getLog(ZKSplitLog.class);
/**
* Gets the full path node name for the log file being split.
* This method will url encode the filename.
* @param zkw zk reference
* @param filename log file name (only the basename)
*/
public static String getEncodedNodeName(ZooKeeperWatcher zkw, String filename) {
return ZKUtil.joinZNode(zkw.znodePaths.splitLogZNode, encode(filename));
}
public static String getFileName(String node) {
String basename = node.substring(node.lastIndexOf('/') + 1);
return decode(basename);
}
static String encode(String s) {
try {
return URLEncoder.encode(s, "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("URLENCODER doesn't support UTF-8");
}
}
static String decode(String s) {
try {
return URLDecoder.decode(s, "UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("URLDecoder doesn't support UTF-8");
}
}
public static String getRescanNode(ZooKeeperWatcher zkw) {
return ZKUtil.joinZNode(zkw.znodePaths.splitLogZNode, "RESCAN");
}
/**
* @param name the last part in path
* @return whether the node name represents a rescan node
*/
public static boolean isRescanNode(String name) {
return name.startsWith("RESCAN");
}
/**
* @param zkw
* @param path the absolute path, starts with '/'
* @return whether the path represents a rescan node
*/
public static boolean isRescanNode(ZooKeeperWatcher zkw, String path) {
String prefix = getRescanNode(zkw);
if (path.length() <= prefix.length()) {
return false;
}
for (int i = 0; i < prefix.length(); i++) {
if (prefix.charAt(i) != path.charAt(i)) {
return false;
}
}
return true;
}
public static boolean isTaskPath(ZooKeeperWatcher zkw, String path) {
String dirname = path.substring(0, path.lastIndexOf('/'));
return dirname.equals(zkw.znodePaths.splitLogZNode);
}
public static Path getSplitLogDir(Path rootdir, String tmpname) {
return new Path(new Path(rootdir, HConstants.SPLIT_LOGDIR_NAME), tmpname);
}
public static String getSplitLogDirTmpComponent(final String worker, String file) {
return worker + "_" + ZKSplitLog.encode(file);
}
public static void markCorrupted(Path rootdir, String logFileName,
FileSystem fs) {
Path file = new Path(getSplitLogDir(rootdir, logFileName), "corrupt");
try {
fs.createNewFile(file);
} catch (IOException e) {
LOG.warn("Could not flag a log file as corrupted. Failed to create " +
file, e);
}
}
public static boolean isCorrupted(Path rootdir, String logFileName,
FileSystem fs) throws IOException {
Path file = new Path(getSplitLogDir(rootdir, logFileName), "corrupt");
boolean isCorrupt;
isCorrupt = fs.exists(file);
return isCorrupt;
}
/*
* Following methods come from SplitLogManager
*/
/**
* check if /hbase/recovering-regions/<current region encoded name>
* exists. Returns true if exists and set watcher as well.
* @param zkw
* @param regionEncodedName region encode name
* @return true when /hbase/recovering-regions/<current region encoded name> exists
* @throws KeeperException
*/
public static boolean
isRegionMarkedRecoveringInZK(ZooKeeperWatcher zkw, String regionEncodedName)
throws KeeperException {
boolean result = false;
String nodePath = ZKUtil.joinZNode(zkw.znodePaths.recoveringRegionsZNode, regionEncodedName);
byte[] node = ZKUtil.getDataAndWatch(zkw, nodePath);
if (node != null) {
result = true;
}
return result;
}
/**
* @param bytes - Content of a failed region server or recovering region znode.
* @return long - The last flushed sequence Id for the region server
*/
public static long parseLastFlushedSequenceIdFrom(final byte[] bytes) {
long lastRecordedFlushedSequenceId = -1l;
try {
lastRecordedFlushedSequenceId = ZKUtil.parseWALPositionFrom(bytes);
} catch (DeserializationException e) {
lastRecordedFlushedSequenceId = -1l;
LOG.warn("Can't parse last flushed sequence Id", e);
}
return lastRecordedFlushedSequenceId;
}
public static void deleteRecoveringRegionZNodes(ZooKeeperWatcher watcher, List regions) {
try {
if (regions == null) {
// remove all children under /home/recovering-regions
LOG.debug("Garbage collecting all recovering region znodes");
ZKUtil.deleteChildrenRecursively(watcher, watcher.znodePaths.recoveringRegionsZNode);
} else {
for (String curRegion : regions) {
String nodePath = ZKUtil.joinZNode(watcher.znodePaths.recoveringRegionsZNode, curRegion);
ZKUtil.deleteNodeRecursively(watcher, nodePath);
}
}
} catch (KeeperException e) {
LOG.warn("Cannot remove recovering regions from ZooKeeper", e);
}
}
/**
* This function is used in distributedLogReplay to fetch last flushed sequence id from ZK
* @param zkw
* @param serverName
* @param encodedRegionName
* @return the last flushed sequence ids recorded in ZK of the region for serverName
* @throws IOException
*/
public static RegionStoreSequenceIds getRegionFlushedSequenceId(ZooKeeperWatcher zkw,
String serverName, String encodedRegionName) throws IOException {
// when SplitLogWorker recovers a region by directly replaying unflushed WAL edits,
// last flushed sequence Id changes when newly assigned RS flushes writes to the region.
// If the newly assigned RS fails again(a chained RS failures scenario), the last flushed
// sequence Id name space (sequence Id only valid for a particular RS instance), changes
// when different newly assigned RS flushes the region.
// Therefore, in this mode we need to fetch last sequence Ids from ZK where we keep history of
// last flushed sequence Id for each failed RS instance.
RegionStoreSequenceIds result = null;
String nodePath = ZKUtil.joinZNode(zkw.znodePaths.recoveringRegionsZNode, encodedRegionName);
nodePath = ZKUtil.joinZNode(nodePath, serverName);
try {
byte[] data;
try {
data = ZKUtil.getData(zkw, nodePath);
} catch (InterruptedException e) {
throw new InterruptedIOException();
}
if (data != null) {
result = ZKUtil.parseRegionStoreSequenceIds(data);
}
} catch (KeeperException e) {
throw new IOException("Cannot get lastFlushedSequenceId from ZooKeeper for server="
+ serverName + "; region=" + encodedRegionName, e);
} catch (DeserializationException e) {
LOG.warn("Can't parse last flushed sequence Id from znode:" + nodePath, e);
}
return result;
}
}