/*
* 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.HashSet;
import java.util.List;
import java.util.Random;
import java.util.Set;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HRegionLocation;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.client.Get;
import org.apache.hadoop.hbase.client.HTable;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.util.test.LoadTestKVGenerator;
/** Creates multiple threads that read and verify previously written data */
public class MultiThreadedReader extends MultiThreadedAction
{
private static final Log LOG = LogFactory.getLog(MultiThreadedReader.class);
private Set<HBaseReaderThread> readers = new HashSet<HBaseReaderThread>();
private final double verifyPercent;
private volatile boolean aborted;
private MultiThreadedWriter writer = null;
/**
* The number of keys verified in a sequence. This will never be larger than
* the total number of keys in the range. The reader might also verify
* random keys when it catches up with the writer.
*/
private final AtomicLong numUniqueKeysVerified = new AtomicLong();
/**
* Default maximum number of read errors to tolerate before shutting down all
* readers.
*/
public static final int DEFAULT_MAX_ERRORS = 10;
/**
* Default "window" size between the last key written by the writer and the
* key that we attempt to read. The lower this number, the stricter our
* testing is. If this is zero, we always attempt to read the highest key
* in the contiguous sequence of keys written by the writers.
*/
public static final int DEFAULT_KEY_WINDOW = 0;
protected AtomicLong numKeysVerified = new AtomicLong(0);
private AtomicLong numReadErrors = new AtomicLong(0);
private AtomicLong numReadFailures = new AtomicLong(0);
private int maxErrors = DEFAULT_MAX_ERRORS;
private int keyWindow = DEFAULT_KEY_WINDOW;
public MultiThreadedReader(Configuration conf, byte[] tableName,
byte[] columnFamily, double verifyPercent) {
super(conf, tableName, columnFamily, "R");
this.verifyPercent = verifyPercent;
}
public void linkToWriter(MultiThreadedWriter writer) {
this.writer = writer;
writer.setTrackInsertedKeys(true);
}
public void setMaxErrors(int maxErrors) {
this.maxErrors = maxErrors;
}
public void setKeyWindow(int keyWindow) {
this.keyWindow = keyWindow;
}
@Override
public void start(long startKey, long endKey, int numThreads)
throws IOException {
super.start(startKey, endKey, numThreads);
if (verbose) {
LOG.debug("Reading keys [" + startKey + ", " + endKey + ")");
}
for (int i = 0; i < numThreads; ++i) {
HBaseReaderThread reader = new HBaseReaderThread(i);
readers.add(reader);
}
startThreads(readers);
}
public class HBaseReaderThread extends Thread {
private final int readerId;
private final HTable table;
private final Random random = new Random();
/** The "current" key being read. Increases from startKey to endKey. */
private long curKey;
/** Time when the thread started */
private long startTimeMs;
/** If we are ahead of the writer and reading a random key. */
private boolean readingRandomKey;
/**
* @param readerId only the keys with this remainder from division by
* {@link #numThreads} will be read by this thread
*/
public HBaseReaderThread(int readerId) throws IOException {
this.readerId = readerId;
table = new HTable(conf, tableName);
setName(getClass().getSimpleName() + "_" + readerId);
}
@Override
public void run() {
try {
runReader();
} finally {
try {
table.close();
} catch (IOException e) {
LOG.error("Error closing table", e);
}
numThreadsWorking.decrementAndGet();
}
}
private void runReader() {
if (verbose) {
LOG.info("Started thread #" + readerId + " for reads...");
}
startTimeMs = System.currentTimeMillis();
curKey = startKey;
while (curKey < endKey && !aborted) {
long k = getNextKeyToRead();
// A sanity check for the key range.
if (k < startKey || k >= endKey) {
numReadErrors.incrementAndGet();
throw new AssertionError("Load tester logic error: proposed key " +
"to read " + k + " is out of range (startKey=" + startKey +
", endKey=" + endKey + ")");
}
if (k % numThreads != readerId ||
writer != null && writer.failedToWriteKey(k)) {
// Skip keys that this thread should not read, as well as the keys
// that we know the writer failed to write.
continue;
}
readKey(k);
if (k == curKey - 1 && !readingRandomKey) {
// We have verified another unique key.
numUniqueKeysVerified.incrementAndGet();
}
}
}
/**
* Should only be used for the concurrent writer/reader workload. The
* maximum key we are allowed to read, subject to the "key window"
* constraint.
*/
private long maxKeyWeCanRead() {
long insertedUpToKey = writer.insertedUpToKey();
if (insertedUpToKey >= endKey - 1) {
// The writer has finished writing our range, so we can read any
// key in the range.
return endKey - 1;
}
return Math.min(endKey - 1, writer.insertedUpToKey() - keyWindow);
}
private long getNextKeyToRead() {
readingRandomKey = false;
if (writer == null || curKey <= maxKeyWeCanRead()) {
return curKey++;
}
// We caught up with the writer. See if we can read any keys at all.
long maxKeyToRead;
while ((maxKeyToRead = maxKeyWeCanRead()) < startKey) {
// The writer has not written sufficient keys for us to be able to read
// anything at all. Sleep a bit. This should only happen in the
// beginning of a load test run.
Threads.sleepWithoutInterrupt(50);
}
if (curKey <= maxKeyToRead) {
// The writer wrote some keys, and we are now allowed to read our
// current key.
return curKey++;
}
// startKey <= maxKeyToRead <= curKey - 1. Read one of the previous keys.
// Don't increment the current key -- we still have to try reading it
// later. Set a flag to make sure that we don't count this key towards
// the set of unique keys we have verified.
readingRandomKey = true;
return startKey + Math.abs(random.nextLong())
% (maxKeyToRead - startKey + 1);
}
private Get readKey(long keyToRead) {
Get get = new Get(
LoadTestKVGenerator.md5PrefixedKey(keyToRead).getBytes());
get.addFamily(columnFamily);
try {
if (verbose) {
LOG.info("[" + readerId + "] " + "Querying key " + keyToRead
+ ", cf " + Bytes.toStringBinary(columnFamily));
}
queryKey(get, random.nextInt(100) < verifyPercent);
} catch (IOException e) {
numReadFailures.addAndGet(1);
LOG.debug("[" + readerId + "] FAILED read, key = " + (keyToRead + "")
+ ", time from start: "
+ (System.currentTimeMillis() - startTimeMs) + " ms");
}
return get;
}
public void queryKey(Get get, boolean verify) throws IOException {
String rowKey = Bytes.toString(get.getRow());
// read the data
long start = System.currentTimeMillis();
Result result = table.get(get);
totalOpTimeMs.addAndGet(System.currentTimeMillis() - start);
numKeys.addAndGet(1);
// if we got no data report error
if (result.isEmpty()) {
HRegionLocation hloc = table.getRegionLocation(
Bytes.toBytes(rowKey));
LOG.info("Key = " + rowKey + ", RegionServer: "
+ hloc.getHostname());
numReadErrors.addAndGet(1);
LOG.error("No data returned, tried to get actions for key = "
+ rowKey + (writer == null ? "" : ", keys inserted by writer: " +
writer.numKeys.get() + ")"));
if (numReadErrors.get() > maxErrors) {
LOG.error("Aborting readers -- found more than " + maxErrors
+ " errors\n");
aborted = true;
}
}
if (result.getFamilyMap(columnFamily) != null) {
// increment number of columns read
numCols.addAndGet(result.getFamilyMap(columnFamily).size());
if (verify) {
// verify the result
List<KeyValue> keyValues = result.list();
for (KeyValue kv : keyValues) {
String qual = new String(kv.getQualifier());
// if something does not look right report it
if (!LoadTestKVGenerator.verify(rowKey, qual, kv.getValue())) {
numReadErrors.addAndGet(1);
LOG.error("Error checking data for key = " + rowKey
+ ", actionId = " + qual);
}
}
numKeysVerified.addAndGet(1);
}
}
}
}
public long getNumReadFailures() {
return numReadFailures.get();
}
public long getNumReadErrors() {
return numReadErrors.get();
}
public long getNumKeysVerified() {
return numKeysVerified.get();
}
public long getNumUniqueKeysVerified() {
return numUniqueKeysVerified.get();
}
@Override
protected String progressInfo() {
StringBuilder sb = new StringBuilder();
appendToStatus(sb, "verified", numKeysVerified.get());
appendToStatus(sb, "READ FAILURES", numReadFailures.get());
appendToStatus(sb, "READ ERRORS", numReadErrors.get());
return sb.toString();
}
}