org.apache.hudi.org.apache.hadoop.hbase.io.hfile.bucket.BucketCache Maven / Gradle / Ivy
/**
* Copyright 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 org.apache.hadoop.hbase.io.hfile.bucket;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NavigableSet;
import java.util.PriorityQueue;
import java.util.Set;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.LongAdder;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.function.Consumer;
import java.util.function.Function;
import org.apache.commons.io.IOUtils;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseConfiguration;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.Admin;
import org.apache.hadoop.hbase.io.ByteBuffAllocator;
import org.apache.hadoop.hbase.io.ByteBuffAllocator.Recycler;
import org.apache.hadoop.hbase.io.HeapSize;
import org.apache.hadoop.hbase.io.hfile.BlockCache;
import org.apache.hadoop.hbase.io.hfile.BlockCacheKey;
import org.apache.hadoop.hbase.io.hfile.BlockCacheUtil;
import org.apache.hadoop.hbase.io.hfile.BlockPriority;
import org.apache.hadoop.hbase.io.hfile.BlockType;
import org.apache.hadoop.hbase.io.hfile.CacheStats;
import org.apache.hadoop.hbase.io.hfile.Cacheable;
import org.apache.hadoop.hbase.io.hfile.CachedBlock;
import org.apache.hadoop.hbase.io.hfile.HFileBlock;
import org.apache.hadoop.hbase.io.hfile.HFileContext;
import org.apache.hadoop.hbase.nio.ByteBuff;
import org.apache.hadoop.hbase.nio.RefCnt;
import org.apache.hadoop.hbase.protobuf.ProtobufMagic;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.util.IdReadWriteLock;
import org.apache.hadoop.hbase.util.IdReadWriteLock.ReferenceType;
import org.apache.hadoop.util.StringUtils;
import org.apache.yetus.audience.InterfaceAudience;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;
import org.apache.hbase.thirdparty.com.google.common.util.concurrent.ThreadFactoryBuilder;
import org.apache.hadoop.hbase.shaded.protobuf.generated.BucketCacheProtos;
/**
* BucketCache uses {@link BucketAllocator} to allocate/free blocks, and uses
* BucketCache#ramCache and BucketCache#backingMap in order to
* determine if a given element is in the cache. The bucket cache can use on-heap or
* off-heap memory {@link ByteBufferIOEngine} or in a file {@link FileIOEngine} to
* store/read the block data.
*
* Eviction is via a similar algorithm as used in
* {@link org.apache.hadoop.hbase.io.hfile.LruBlockCache}
*
*
BucketCache can be used as mainly a block cache (see
* {@link org.apache.hadoop.hbase.io.hfile.CombinedBlockCache}), combined with
* a BlockCache to decrease CMS GC and heap fragmentation.
*
*
It also can be used as a secondary cache (e.g. using a file on ssd/fusionio to store
* blocks) to enlarge cache space via a victim cache.
*/
@InterfaceAudience.Private
public class BucketCache implements BlockCache, HeapSize {
private static final Logger LOG = LoggerFactory.getLogger(BucketCache.class);
/** Priority buckets config */
static final String SINGLE_FACTOR_CONFIG_NAME = "hbase.bucketcache.single.factor";
static final String MULTI_FACTOR_CONFIG_NAME = "hbase.bucketcache.multi.factor";
static final String MEMORY_FACTOR_CONFIG_NAME = "hbase.bucketcache.memory.factor";
static final String EXTRA_FREE_FACTOR_CONFIG_NAME = "hbase.bucketcache.extrafreefactor";
static final String ACCEPT_FACTOR_CONFIG_NAME = "hbase.bucketcache.acceptfactor";
static final String MIN_FACTOR_CONFIG_NAME = "hbase.bucketcache.minfactor";
/** Priority buckets */
static final float DEFAULT_SINGLE_FACTOR = 0.25f;
static final float DEFAULT_MULTI_FACTOR = 0.50f;
static final float DEFAULT_MEMORY_FACTOR = 0.25f;
static final float DEFAULT_MIN_FACTOR = 0.85f;
private static final float DEFAULT_EXTRA_FREE_FACTOR = 0.10f;
private static final float DEFAULT_ACCEPT_FACTOR = 0.95f;
// Number of blocks to clear for each of the bucket size that is full
private static final int DEFAULT_FREE_ENTIRE_BLOCK_FACTOR = 2;
/** Statistics thread */
private static final int statThreadPeriod = 5 * 60;
final static int DEFAULT_WRITER_THREADS = 3;
final static int DEFAULT_WRITER_QUEUE_ITEMS = 64;
// Store/read block data
transient final IOEngine ioEngine;
// Store the block in this map before writing it to cache
transient final RAMCache ramCache;
// In this map, store the block's meta data like offset, length
transient ConcurrentHashMap backingMap;
/**
* Flag if the cache is enabled or not... We shut it off if there are IO
* errors for some time, so that Bucket IO exceptions/errors don't bring down
* the HBase server.
*/
private volatile boolean cacheEnabled;
/**
* A list of writer queues. We have a queue per {@link WriterThread} we have running.
* In other words, the work adding blocks to the BucketCache is divided up amongst the
* running WriterThreads. Its done by taking hash of the cache key modulo queue count.
* WriterThread when it runs takes whatever has been recently added and 'drains' the entries
* to the BucketCache. It then updates the ramCache and backingMap accordingly.
*/
transient final ArrayList> writerQueues = new ArrayList<>();
transient final WriterThread[] writerThreads;
/** Volatile boolean to track if free space is in process or not */
private volatile boolean freeInProgress = false;
private transient final Lock freeSpaceLock = new ReentrantLock();
private final LongAdder realCacheSize = new LongAdder();
private final LongAdder heapSize = new LongAdder();
/** Current number of cached elements */
private final LongAdder blockNumber = new LongAdder();
/** Cache access count (sequential ID) */
private final AtomicLong accessCount = new AtomicLong();
private static final int DEFAULT_CACHE_WAIT_TIME = 50;
/**
* Used in tests. If this flag is false and the cache speed is very fast,
* bucket cache will skip some blocks when caching. If the flag is true, we
* will wait until blocks are flushed to IOEngine.
*/
boolean wait_when_cache = false;
private final BucketCacheStats cacheStats = new BucketCacheStats();
private final String persistencePath;
private final long cacheCapacity;
/** Approximate block size */
private final long blockSize;
/** Duration of IO errors tolerated before we disable cache, 1 min as default */
private final int ioErrorsTolerationDuration;
// 1 min
public static final int DEFAULT_ERROR_TOLERATION_DURATION = 60 * 1000;
// Start time of first IO error when reading or writing IO Engine, it will be
// reset after a successful read/write.
private volatile long ioErrorStartTime = -1;
/**
* A ReentrantReadWriteLock to lock on a particular block identified by offset.
* The purpose of this is to avoid freeing the block which is being read.
*
* Key set of offsets in BucketCache is limited so soft reference is the best choice here.
*/
transient final IdReadWriteLock offsetLock = new IdReadWriteLock<>(ReferenceType.SOFT);
private final NavigableSet blocksByHFile = new ConcurrentSkipListSet<>((a, b) -> {
int nameComparison = a.getHfileName().compareTo(b.getHfileName());
if (nameComparison != 0) {
return nameComparison;
}
return Long.compare(a.getOffset(), b.getOffset());
});
/** Statistics thread schedule pool (for heavy debugging, could remove) */
private transient final ScheduledExecutorService scheduleThreadPool =
Executors.newScheduledThreadPool(1,
new ThreadFactoryBuilder().setNameFormat("BucketCacheStatsExecutor").setDaemon(true).build());
// Allocate or free space for the block
private transient BucketAllocator bucketAllocator;
/** Acceptable size of cache (no evictions if size < acceptable) */
private float acceptableFactor;
/** Minimum threshold of cache (when evicting, evict until size < min) */
private float minFactor;
/** Free this floating point factor of extra blocks when evicting. For example free the number of blocks requested * (1 + extraFreeFactor) */
private float extraFreeFactor;
/** Single access bucket size */
private float singleFactor;
/** Multiple access bucket size */
private float multiFactor;
/** In-memory bucket size */
private float memoryFactor;
private static final String FILE_VERIFY_ALGORITHM =
"hbase.bucketcache.persistent.file.integrity.check.algorithm";
private static final String DEFAULT_FILE_VERIFY_ALGORITHM = "MD5";
/**
* Use {@link java.security.MessageDigest} class's encryption algorithms to check
* persistent file integrity, default algorithm is MD5
* */
private String algorithm;
/* Tracing failed Bucket Cache allocations. */
private long allocFailLogPrevTs; // time of previous log event for allocation failure.
private static final int ALLOCATION_FAIL_LOG_TIME_PERIOD = 60000; // Default 1 minute.
public BucketCache(String ioEngineName, long capacity, int blockSize, int[] bucketSizes,
int writerThreadNum, int writerQLen, String persistencePath) throws IOException {
this(ioEngineName, capacity, blockSize, bucketSizes, writerThreadNum, writerQLen,
persistencePath, DEFAULT_ERROR_TOLERATION_DURATION, HBaseConfiguration.create());
}
public BucketCache(String ioEngineName, long capacity, int blockSize, int[] bucketSizes,
int writerThreadNum, int writerQLen, String persistencePath, int ioErrorsTolerationDuration,
Configuration conf) throws IOException {
this.algorithm = conf.get(FILE_VERIFY_ALGORITHM, DEFAULT_FILE_VERIFY_ALGORITHM);
this.ioEngine = getIOEngineFromName(ioEngineName, capacity, persistencePath);
this.writerThreads = new WriterThread[writerThreadNum];
long blockNumCapacity = capacity / blockSize;
if (blockNumCapacity >= Integer.MAX_VALUE) {
// Enough for about 32TB of cache!
throw new IllegalArgumentException("Cache capacity is too large, only support 32TB now");
}
this.acceptableFactor = conf.getFloat(ACCEPT_FACTOR_CONFIG_NAME, DEFAULT_ACCEPT_FACTOR);
this.minFactor = conf.getFloat(MIN_FACTOR_CONFIG_NAME, DEFAULT_MIN_FACTOR);
this.extraFreeFactor = conf.getFloat(EXTRA_FREE_FACTOR_CONFIG_NAME, DEFAULT_EXTRA_FREE_FACTOR);
this.singleFactor = conf.getFloat(SINGLE_FACTOR_CONFIG_NAME, DEFAULT_SINGLE_FACTOR);
this.multiFactor = conf.getFloat(MULTI_FACTOR_CONFIG_NAME, DEFAULT_MULTI_FACTOR);
this.memoryFactor = conf.getFloat(MEMORY_FACTOR_CONFIG_NAME, DEFAULT_MEMORY_FACTOR);
sanityCheckConfigs();
LOG.info("Instantiating BucketCache with acceptableFactor: " + acceptableFactor + ", minFactor: " + minFactor +
", extraFreeFactor: " + extraFreeFactor + ", singleFactor: " + singleFactor + ", multiFactor: " + multiFactor +
", memoryFactor: " + memoryFactor);
this.cacheCapacity = capacity;
this.persistencePath = persistencePath;
this.blockSize = blockSize;
this.ioErrorsTolerationDuration = ioErrorsTolerationDuration;
this.allocFailLogPrevTs = 0;
bucketAllocator = new BucketAllocator(capacity, bucketSizes);
for (int i = 0; i < writerThreads.length; ++i) {
writerQueues.add(new ArrayBlockingQueue<>(writerQLen));
}
assert writerQueues.size() == writerThreads.length;
this.ramCache = new RAMCache();
this.backingMap = new ConcurrentHashMap<>((int) blockNumCapacity);
if (ioEngine.isPersistent() && persistencePath != null) {
try {
retrieveFromFile(bucketSizes);
} catch (IOException ioex) {
LOG.error("Can't restore from file[" + persistencePath + "] because of ", ioex);
}
}
final String threadName = Thread.currentThread().getName();
this.cacheEnabled = true;
for (int i = 0; i < writerThreads.length; ++i) {
writerThreads[i] = new WriterThread(writerQueues.get(i));
writerThreads[i].setName(threadName + "-BucketCacheWriter-" + i);
writerThreads[i].setDaemon(true);
}
startWriterThreads();
// Run the statistics thread periodically to print the cache statistics log
// TODO: Add means of turning this off. Bit obnoxious running thread just to make a log
// every five minutes.
this.scheduleThreadPool.scheduleAtFixedRate(new StatisticsThread(this),
statThreadPeriod, statThreadPeriod, TimeUnit.SECONDS);
LOG.info("Started bucket cache; ioengine=" + ioEngineName +
", capacity=" + StringUtils.byteDesc(capacity) +
", blockSize=" + StringUtils.byteDesc(blockSize) + ", writerThreadNum=" +
writerThreadNum + ", writerQLen=" + writerQLen + ", persistencePath=" +
persistencePath + ", bucketAllocator=" + this.bucketAllocator.getClass().getName());
}
private void sanityCheckConfigs() {
Preconditions.checkArgument(acceptableFactor <= 1 && acceptableFactor >= 0, ACCEPT_FACTOR_CONFIG_NAME + " must be between 0.0 and 1.0");
Preconditions.checkArgument(minFactor <= 1 && minFactor >= 0, MIN_FACTOR_CONFIG_NAME + " must be between 0.0 and 1.0");
Preconditions.checkArgument(minFactor <= acceptableFactor, MIN_FACTOR_CONFIG_NAME + " must be <= " + ACCEPT_FACTOR_CONFIG_NAME);
Preconditions.checkArgument(extraFreeFactor >= 0, EXTRA_FREE_FACTOR_CONFIG_NAME + " must be greater than 0.0");
Preconditions.checkArgument(singleFactor <= 1 && singleFactor >= 0, SINGLE_FACTOR_CONFIG_NAME + " must be between 0.0 and 1.0");
Preconditions.checkArgument(multiFactor <= 1 && multiFactor >= 0, MULTI_FACTOR_CONFIG_NAME + " must be between 0.0 and 1.0");
Preconditions.checkArgument(memoryFactor <= 1 && memoryFactor >= 0, MEMORY_FACTOR_CONFIG_NAME + " must be between 0.0 and 1.0");
Preconditions.checkArgument((singleFactor + multiFactor + memoryFactor) == 1, SINGLE_FACTOR_CONFIG_NAME + ", " +
MULTI_FACTOR_CONFIG_NAME + ", and " + MEMORY_FACTOR_CONFIG_NAME + " segments must add up to 1.0");
}
/**
* Called by the constructor to start the writer threads. Used by tests that need to override
* starting the threads.
*/
protected void startWriterThreads() {
for (WriterThread thread : writerThreads) {
thread.start();
}
}
boolean isCacheEnabled() {
return this.cacheEnabled;
}
@Override
public long getMaxSize() {
return this.cacheCapacity;
}
public String getIoEngine() {
return ioEngine.toString();
}
/**
* Get the IOEngine from the IO engine name
* @param ioEngineName
* @param capacity
* @param persistencePath
* @return the IOEngine
* @throws IOException
*/
private IOEngine getIOEngineFromName(String ioEngineName, long capacity, String persistencePath)
throws IOException {
if (ioEngineName.startsWith("file:") || ioEngineName.startsWith("files:")) {
// In order to make the usage simple, we only need the prefix 'files:' in
// document whether one or multiple file(s), but also support 'file:' for
// the compatibility
String[] filePaths = ioEngineName.substring(ioEngineName.indexOf(":") + 1)
.split(FileIOEngine.FILE_DELIMITER);
return new FileIOEngine(capacity, persistencePath != null, filePaths);
} else if (ioEngineName.startsWith("offheap")) {
return new ByteBufferIOEngine(capacity);
} else if (ioEngineName.startsWith("mmap:")) {
return new ExclusiveMemoryMmapIOEngine(ioEngineName.substring(5), capacity);
} else if (ioEngineName.startsWith("pmem:")) {
// This mode of bucket cache creates an IOEngine over a file on the persistent memory
// device. Since the persistent memory device has its own address space the contents
// mapped to this address space does not get swapped out like in the case of mmapping
// on to DRAM. Hence the cells created out of the hfile blocks in the pmem bucket cache
// can be directly referred to without having to copy them onheap. Once the RPC is done,
// the blocks can be returned back as in case of ByteBufferIOEngine.
return new SharedMemoryMmapIOEngine(ioEngineName.substring(5), capacity);
} else {
throw new IllegalArgumentException(
"Don't understand io engine name for cache- prefix with file:, files:, mmap: or offheap");
}
}
/**
* Cache the block with the specified name and buffer.
* @param cacheKey block's cache key
* @param buf block buffer
*/
@Override
public void cacheBlock(BlockCacheKey cacheKey, Cacheable buf) {
cacheBlock(cacheKey, buf, false);
}
/**
* Cache the block with the specified name and buffer.
* @param cacheKey block's cache key
* @param cachedItem block buffer
* @param inMemory if block is in-memory
*/
@Override
public void cacheBlock(BlockCacheKey cacheKey, Cacheable cachedItem, boolean inMemory) {
cacheBlockWithWait(cacheKey, cachedItem, inMemory, wait_when_cache);
}
/**
* Cache the block to ramCache
* @param cacheKey block's cache key
* @param cachedItem block buffer
* @param inMemory if block is in-memory
* @param wait if true, blocking wait when queue is full
*/
public void cacheBlockWithWait(BlockCacheKey cacheKey, Cacheable cachedItem, boolean inMemory,
boolean wait) {
if (cacheEnabled) {
if (backingMap.containsKey(cacheKey) || ramCache.containsKey(cacheKey)) {
if (shouldReplaceExistingCacheBlock(cacheKey, cachedItem)) {
BucketEntry bucketEntry = backingMap.get(cacheKey);
if (bucketEntry != null && bucketEntry.isRpcRef()) {
// avoid replace when there are RPC refs for the bucket entry in bucket cache
return;
}
cacheBlockWithWaitInternal(cacheKey, cachedItem, inMemory, wait);
}
} else {
cacheBlockWithWaitInternal(cacheKey, cachedItem, inMemory, wait);
}
}
}
protected boolean shouldReplaceExistingCacheBlock(BlockCacheKey cacheKey, Cacheable newBlock) {
return BlockCacheUtil.shouldReplaceExistingCacheBlock(this, cacheKey, newBlock);
}
protected void cacheBlockWithWaitInternal(BlockCacheKey cacheKey, Cacheable cachedItem,
boolean inMemory, boolean wait) {
if (!cacheEnabled) {
return;
}
LOG.trace("Caching key={}, item={}", cacheKey, cachedItem);
// Stuff the entry into the RAM cache so it can get drained to the persistent store
RAMQueueEntry re =
new RAMQueueEntry(cacheKey, cachedItem, accessCount.incrementAndGet(), inMemory);
/**
* Don't use ramCache.put(cacheKey, re) here. because there may be a existing entry with same
* key in ramCache, the heap size of bucket cache need to update if replacing entry from
* ramCache. But WriterThread will also remove entry from ramCache and update heap size, if
* using ramCache.put(), It's possible that the removed entry in WriterThread is not the correct
* one, then the heap size will mess up (HBASE-20789)
*/
if (ramCache.putIfAbsent(cacheKey, re) != null) {
return;
}
int queueNum = (cacheKey.hashCode() & 0x7FFFFFFF) % writerQueues.size();
BlockingQueue bq = writerQueues.get(queueNum);
boolean successfulAddition = false;
if (wait) {
try {
successfulAddition = bq.offer(re, DEFAULT_CACHE_WAIT_TIME, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
} else {
successfulAddition = bq.offer(re);
}
if (!successfulAddition) {
ramCache.remove(cacheKey);
cacheStats.failInsert();
} else {
this.blockNumber.increment();
this.heapSize.add(cachedItem.heapSize());
blocksByHFile.add(cacheKey);
}
}
/**
* Get the buffer of the block with the specified key.
* @param key block's cache key
* @param caching true if the caller caches blocks on cache misses
* @param repeat Whether this is a repeat lookup for the same block
* @param updateCacheMetrics Whether we should update cache metrics or not
* @return buffer of specified cache key, or null if not in cache
*/
@Override
public Cacheable getBlock(BlockCacheKey key, boolean caching, boolean repeat,
boolean updateCacheMetrics) {
if (!cacheEnabled) {
return null;
}
RAMQueueEntry re = ramCache.get(key);
if (re != null) {
if (updateCacheMetrics) {
cacheStats.hit(caching, key.isPrimary(), key.getBlockType());
}
re.access(accessCount.incrementAndGet());
return re.getData();
}
BucketEntry bucketEntry = backingMap.get(key);
if (bucketEntry != null) {
long start = System.nanoTime();
ReentrantReadWriteLock lock = offsetLock.getLock(bucketEntry.offset());
try {
lock.readLock().lock();
// We can not read here even if backingMap does contain the given key because its offset
// maybe changed. If we lock BlockCacheKey instead of offset, then we can only check
// existence here.
if (bucketEntry.equals(backingMap.get(key))) {
// Read the block from IOEngine based on the bucketEntry's offset and length, NOTICE: the
// block will use the refCnt of bucketEntry, which means if two HFileBlock mapping to
// the same BucketEntry, then all of the three will share the same refCnt.
Cacheable cachedBlock = ioEngine.read(bucketEntry);
if (ioEngine.usesSharedMemory()) {
// If IOEngine use shared memory, cachedBlock and BucketEntry will share the
// same RefCnt, do retain here, in order to count the number of RPC references
cachedBlock.retain();
}
// Update the cache statistics.
if (updateCacheMetrics) {
cacheStats.hit(caching, key.isPrimary(), key.getBlockType());
cacheStats.ioHit(System.nanoTime() - start);
}
bucketEntry.access(accessCount.incrementAndGet());
if (this.ioErrorStartTime > 0) {
ioErrorStartTime = -1;
}
return cachedBlock;
}
} catch (IOException ioex) {
LOG.error("Failed reading block " + key + " from bucket cache", ioex);
checkIOErrorIsTolerated();
} finally {
lock.readLock().unlock();
}
}
if (!repeat && updateCacheMetrics) {
cacheStats.miss(caching, key.isPrimary(), key.getBlockType());
}
return null;
}
/**
* This method is invoked after the bucketEntry is removed from {@link BucketCache#backingMap}
*/
void blockEvicted(BlockCacheKey cacheKey, BucketEntry bucketEntry, boolean decrementBlockNumber) {
bucketEntry.markAsEvicted();
blocksByHFile.remove(cacheKey);
if (decrementBlockNumber) {
this.blockNumber.decrement();
}
cacheStats.evicted(bucketEntry.getCachedTime(), cacheKey.isPrimary());
}
/**
* Free the {{@link BucketEntry} actually,which could only be invoked when the
* {@link BucketEntry#refCnt} becoming 0.
*/
void freeBucketEntry(BucketEntry bucketEntry) {
bucketAllocator.freeBlock(bucketEntry.offset());
realCacheSize.add(-1 * bucketEntry.getLength());
}
/**
* Try to evict the block from {@link BlockCache} by force. We'll call this in few cases:
* 1. Close an HFile, and clear all cached blocks.
* 2. Call {@link Admin#clearBlockCache(TableName)} to clear all blocks for a given table.
*
* Firstly, we'll try to remove the block from RAMCache,and then try to evict from backingMap.
* Here we evict the block from backingMap immediately, but only free the reference from bucket
* cache by calling {@link BucketEntry#markedAsEvicted}. If there're still some RPC referring this
* block, block can only be de-allocated when all of them release the block.
*
* NOTICE: we need to grab the write offset lock firstly before releasing the reference from
* bucket cache. if we don't, we may read an {@link BucketEntry} with refCnt = 0 when
* {@link BucketCache#getBlock(BlockCacheKey, boolean, boolean, boolean)}, it's a memory leak.
* @param cacheKey Block to evict
* @return true to indicate whether we've evicted successfully or not.
*/
@Override
public boolean evictBlock(BlockCacheKey cacheKey) {
return doEvictBlock(cacheKey, null);
}
/**
* Evict the {@link BlockCacheKey} and {@link BucketEntry} from {@link BucketCache#backingMap} and
* {@link BucketCache#ramCache}.
* NOTE:When Evict from {@link BucketCache#backingMap},only the matched {@link BlockCacheKey} and
* {@link BucketEntry} could be removed.
* @param cacheKey {@link BlockCacheKey} to evict.
* @param bucketEntry {@link BucketEntry} matched {@link BlockCacheKey} to evict.
* @return true to indicate whether we've evicted successfully or not.
*/
private boolean doEvictBlock(BlockCacheKey cacheKey, BucketEntry bucketEntry) {
if (!cacheEnabled) {
return false;
}
boolean existedInRamCache = removeFromRamCache(cacheKey);
if (bucketEntry == null) {
bucketEntry = backingMap.get(cacheKey);
}
final BucketEntry bucketEntryToUse = bucketEntry;
if (bucketEntryToUse == null) {
if (existedInRamCache) {
cacheStats.evicted(0, cacheKey.isPrimary());
}
return existedInRamCache;
} else {
return bucketEntryToUse.withWriteLock(offsetLock, () -> {
if (backingMap.remove(cacheKey, bucketEntryToUse)) {
blockEvicted(cacheKey, bucketEntryToUse, !existedInRamCache);
return true;
}
return false;
});
}
}
/**
*
* Create the {@link Recycler} for {@link BucketEntry#refCnt},which would be used as
* {@link RefCnt#recycler} of {@link HFileBlock#buf} returned from {@link BucketCache#getBlock}.
* NOTE: for {@link BucketCache#getBlock},the {@link RefCnt#recycler} of {@link HFileBlock#buf}
* from {@link BucketCache#backingMap} and {@link BucketCache#ramCache} are different:
* 1.For {@link RefCnt#recycler} of {@link HFileBlock#buf} from {@link BucketCache#backingMap},
* it is the return value of current {@link BucketCache#createRecycler} method.
*
* 2.For {@link RefCnt#recycler} of {@link HFileBlock#buf} from {@link BucketCache#ramCache},
* it is {@link ByteBuffAllocator#putbackBuffer}.
*
*/
private Recycler createRecycler(final BucketEntry bucketEntry) {
return () -> {
freeBucketEntry(bucketEntry);
return;
};
}
/**
* NOTE: This method is only for test.
*/
public boolean evictBlockIfNoRpcReferenced(BlockCacheKey blockCacheKey) {
BucketEntry bucketEntry = backingMap.get(blockCacheKey);
if (bucketEntry == null) {
return false;
}
return evictBucketEntryIfNoRpcReferenced(blockCacheKey, bucketEntry);
}
/**
* Evict {@link BlockCacheKey} and its corresponding {@link BucketEntry} only if
* {@link BucketEntry#isRpcRef} is false.
* NOTE:When evict from {@link BucketCache#backingMap},only the matched {@link BlockCacheKey} and
* {@link BucketEntry} could be removed.
* @param blockCacheKey {@link BlockCacheKey} to evict.
* @param bucketEntry {@link BucketEntry} matched {@link BlockCacheKey} to evict.
* @return true to indicate whether we've evicted successfully or not.
*/
boolean evictBucketEntryIfNoRpcReferenced(BlockCacheKey blockCacheKey, BucketEntry bucketEntry) {
if (!bucketEntry.isRpcRef()) {
return doEvictBlock(blockCacheKey, bucketEntry);
}
return false;
}
protected boolean removeFromRamCache(BlockCacheKey cacheKey) {
return ramCache.remove(cacheKey, re -> {
if (re != null) {
this.blockNumber.decrement();
this.heapSize.add(-1 * re.getData().heapSize());
}
});
}
/*
* Statistics thread. Periodically output cache statistics to the log.
*/
private static class StatisticsThread extends Thread {
private final BucketCache bucketCache;
public StatisticsThread(BucketCache bucketCache) {
super("BucketCacheStatsThread");
setDaemon(true);
this.bucketCache = bucketCache;
}
@Override
public void run() {
bucketCache.logStats();
}
}
public void logStats() {
long totalSize = bucketAllocator.getTotalSize();
long usedSize = bucketAllocator.getUsedSize();
long freeSize = totalSize - usedSize;
long cacheSize = getRealCacheSize();
LOG.info("failedBlockAdditions=" + cacheStats.getFailedInserts() + ", " +
"totalSize=" + StringUtils.byteDesc(totalSize) + ", " +
"freeSize=" + StringUtils.byteDesc(freeSize) + ", " +
"usedSize=" + StringUtils.byteDesc(usedSize) +", " +
"cacheSize=" + StringUtils.byteDesc(cacheSize) +", " +
"accesses=" + cacheStats.getRequestCount() + ", " +
"hits=" + cacheStats.getHitCount() + ", " +
"IOhitsPerSecond=" + cacheStats.getIOHitsPerSecond() + ", " +
"IOTimePerHit=" + String.format("%.2f", cacheStats.getIOTimePerHit())+ ", " +
"hitRatio=" + (cacheStats.getHitCount() == 0 ? "0," :
(StringUtils.formatPercent(cacheStats.getHitRatio(), 2)+ ", ")) +
"cachingAccesses=" + cacheStats.getRequestCachingCount() + ", " +
"cachingHits=" + cacheStats.getHitCachingCount() + ", " +
"cachingHitsRatio=" +(cacheStats.getHitCachingCount() == 0 ? "0," :
(StringUtils.formatPercent(cacheStats.getHitCachingRatio(), 2)+ ", ")) +
"evictions=" + cacheStats.getEvictionCount() + ", " +
"evicted=" + cacheStats.getEvictedCount() + ", " +
"evictedPerRun=" + cacheStats.evictedPerEviction() + ", " +
"allocationFailCount=" + cacheStats.getAllocationFailCount());
cacheStats.reset();
}
public long getRealCacheSize() {
return this.realCacheSize.sum();
}
public long acceptableSize() {
return (long) Math.floor(bucketAllocator.getTotalSize() * acceptableFactor);
}
long getPartitionSize(float partitionFactor) {
return (long) Math.floor(bucketAllocator.getTotalSize() * partitionFactor * minFactor);
}
/**
* Return the count of bucketSizeinfos still need free space
*/
private int bucketSizesAboveThresholdCount(float minFactor) {
BucketAllocator.IndexStatistics[] stats = bucketAllocator.getIndexStatistics();
int fullCount = 0;
for (int i = 0; i < stats.length; i++) {
long freeGoal = (long) Math.floor(stats[i].totalCount() * (1 - minFactor));
freeGoal = Math.max(freeGoal, 1);
if (stats[i].freeCount() < freeGoal) {
fullCount++;
}
}
return fullCount;
}
/**
* This method will find the buckets that are minimally occupied
* and are not reference counted and will free them completely
* without any constraint on the access times of the elements,
* and as a process will completely free at most the number of buckets
* passed, sometimes it might not due to changing refCounts
*
* @param completelyFreeBucketsNeeded number of buckets to free
**/
private void freeEntireBuckets(int completelyFreeBucketsNeeded) {
if (completelyFreeBucketsNeeded != 0) {
// First we will build a set where the offsets are reference counted, usually
// this set is small around O(Handler Count) unless something else is wrong
Set inUseBuckets = new HashSet<>();
backingMap.forEach((k, be) -> {
if (be.isRpcRef()) {
inUseBuckets.add(bucketAllocator.getBucketIndex(be.offset()));
}
});
Set candidateBuckets =
bucketAllocator.getLeastFilledBuckets(inUseBuckets, completelyFreeBucketsNeeded);
for (Map.Entry entry : backingMap.entrySet()) {
if (candidateBuckets.contains(bucketAllocator.getBucketIndex(entry.getValue().offset()))) {
evictBucketEntryIfNoRpcReferenced(entry.getKey(), entry.getValue());
}
}
}
}
/**
* Free the space if the used size reaches acceptableSize() or one size block
* couldn't be allocated. When freeing the space, we use the LRU algorithm and
* ensure there must be some blocks evicted
* @param why Why we are being called
*/
private void freeSpace(final String why) {
// Ensure only one freeSpace progress at a time
if (!freeSpaceLock.tryLock()) {
return;
}
try {
freeInProgress = true;
long bytesToFreeWithoutExtra = 0;
// Calculate free byte for each bucketSizeinfo
StringBuilder msgBuffer = LOG.isDebugEnabled()? new StringBuilder(): null;
BucketAllocator.IndexStatistics[] stats = bucketAllocator.getIndexStatistics();
long[] bytesToFreeForBucket = new long[stats.length];
for (int i = 0; i < stats.length; i++) {
bytesToFreeForBucket[i] = 0;
long freeGoal = (long) Math.floor(stats[i].totalCount() * (1 - minFactor));
freeGoal = Math.max(freeGoal, 1);
if (stats[i].freeCount() < freeGoal) {
bytesToFreeForBucket[i] = stats[i].itemSize() * (freeGoal - stats[i].freeCount());
bytesToFreeWithoutExtra += bytesToFreeForBucket[i];
if (msgBuffer != null) {
msgBuffer.append("Free for bucketSize(" + stats[i].itemSize() + ")="
+ StringUtils.byteDesc(bytesToFreeForBucket[i]) + ", ");
}
}
}
if (msgBuffer != null) {
msgBuffer.append("Free for total=" + StringUtils.byteDesc(bytesToFreeWithoutExtra) + ", ");
}
if (bytesToFreeWithoutExtra <= 0) {
return;
}
long currentSize = bucketAllocator.getUsedSize();
long totalSize = bucketAllocator.getTotalSize();
if (LOG.isDebugEnabled() && msgBuffer != null) {
LOG.debug("Free started because \"" + why + "\"; " + msgBuffer.toString() +
" of current used=" + StringUtils.byteDesc(currentSize) + ", actual cacheSize=" +
StringUtils.byteDesc(realCacheSize.sum()) + ", total=" + StringUtils.byteDesc(totalSize));
}
long bytesToFreeWithExtra = (long) Math.floor(bytesToFreeWithoutExtra
* (1 + extraFreeFactor));
// Instantiate priority buckets
BucketEntryGroup bucketSingle = new BucketEntryGroup(bytesToFreeWithExtra,
blockSize, getPartitionSize(singleFactor));
BucketEntryGroup bucketMulti = new BucketEntryGroup(bytesToFreeWithExtra,
blockSize, getPartitionSize(multiFactor));
BucketEntryGroup bucketMemory = new BucketEntryGroup(bytesToFreeWithExtra,
blockSize, getPartitionSize(memoryFactor));
// Scan entire map putting bucket entry into appropriate bucket entry
// group
for (Map.Entry bucketEntryWithKey : backingMap.entrySet()) {
switch (bucketEntryWithKey.getValue().getPriority()) {
case SINGLE: {
bucketSingle.add(bucketEntryWithKey);
break;
}
case MULTI: {
bucketMulti.add(bucketEntryWithKey);
break;
}
case MEMORY: {
bucketMemory.add(bucketEntryWithKey);
break;
}
}
}
PriorityQueue bucketQueue = new PriorityQueue<>(3,
Comparator.comparingLong(BucketEntryGroup::overflow));
bucketQueue.add(bucketSingle);
bucketQueue.add(bucketMulti);
bucketQueue.add(bucketMemory);
int remainingBuckets = bucketQueue.size();
long bytesFreed = 0;
BucketEntryGroup bucketGroup;
while ((bucketGroup = bucketQueue.poll()) != null) {
long overflow = bucketGroup.overflow();
if (overflow > 0) {
long bucketBytesToFree = Math.min(overflow,
(bytesToFreeWithoutExtra - bytesFreed) / remainingBuckets);
bytesFreed += bucketGroup.free(bucketBytesToFree);
}
remainingBuckets--;
}
// Check and free if there are buckets that still need freeing of space
if (bucketSizesAboveThresholdCount(minFactor) > 0) {
bucketQueue.clear();
remainingBuckets = 3;
bucketQueue.add(bucketSingle);
bucketQueue.add(bucketMulti);
bucketQueue.add(bucketMemory);
while ((bucketGroup = bucketQueue.poll()) != null) {
long bucketBytesToFree = (bytesToFreeWithExtra - bytesFreed) / remainingBuckets;
bytesFreed += bucketGroup.free(bucketBytesToFree);
remainingBuckets--;
}
}
// Even after the above free we might still need freeing because of the
// De-fragmentation of the buckets (also called Slab Calcification problem), i.e
// there might be some buckets where the occupancy is very sparse and thus are not
// yielding the free for the other bucket sizes, the fix for this to evict some
// of the buckets, we do this by evicting the buckets that are least fulled
freeEntireBuckets(DEFAULT_FREE_ENTIRE_BLOCK_FACTOR *
bucketSizesAboveThresholdCount(1.0f));
if (LOG.isDebugEnabled()) {
long single = bucketSingle.totalSize();
long multi = bucketMulti.totalSize();
long memory = bucketMemory.totalSize();
if (LOG.isDebugEnabled()) {
LOG.debug("Bucket cache free space completed; " + "freed="
+ StringUtils.byteDesc(bytesFreed) + ", " + "total="
+ StringUtils.byteDesc(totalSize) + ", " + "single="
+ StringUtils.byteDesc(single) + ", " + "multi="
+ StringUtils.byteDesc(multi) + ", " + "memory="
+ StringUtils.byteDesc(memory));
}
}
} catch (Throwable t) {
LOG.warn("Failed freeing space", t);
} finally {
cacheStats.evict();
freeInProgress = false;
freeSpaceLock.unlock();
}
}
// This handles flushing the RAM cache to IOEngine.
class WriterThread extends Thread {
private final BlockingQueue inputQueue;
private volatile boolean writerEnabled = true;
WriterThread(BlockingQueue queue) {
super("BucketCacheWriterThread");
this.inputQueue = queue;
}
// Used for test
void disableWriter() {
this.writerEnabled = false;
}
@Override
public void run() {
List entries = new ArrayList<>();
try {
while (cacheEnabled && writerEnabled) {
try {
try {
// Blocks
entries = getRAMQueueEntries(inputQueue, entries);
} catch (InterruptedException ie) {
if (!cacheEnabled || !writerEnabled) {
break;
}
}
doDrain(entries);
} catch (Exception ioe) {
LOG.error("WriterThread encountered error", ioe);
}
}
} catch (Throwable t) {
LOG.warn("Failed doing drain", t);
}
LOG.info(this.getName() + " exiting, cacheEnabled=" + cacheEnabled);
}
}
/**
* Put the new bucket entry into backingMap. Notice that we are allowed to replace the existing
* cache with a new block for the same cache key. there's a corner case: one thread cache a block
* in ramCache, copy to io-engine and add a bucket entry to backingMap. Caching another new block
* with the same cache key do the same thing for the same cache key, so if not evict the previous
* bucket entry, then memory leak happen because the previous bucketEntry is gone but the
* bucketAllocator do not free its memory.
* @see BlockCacheUtil#shouldReplaceExistingCacheBlock(BlockCache blockCache,BlockCacheKey
* cacheKey, Cacheable newBlock)
* @param key Block cache key
* @param bucketEntry Bucket entry to put into backingMap.
*/
protected void putIntoBackingMap(BlockCacheKey key, BucketEntry bucketEntry) {
BucketEntry previousEntry = backingMap.put(key, bucketEntry);
if (previousEntry != null && previousEntry != bucketEntry) {
previousEntry.withWriteLock(offsetLock, () -> {
blockEvicted(key, previousEntry, false);
return null;
});
}
}
/**
* Prepare and return a warning message for Bucket Allocator Exception
* @param re The RAMQueueEntry for which the exception was thrown.
* @return A warning message created from the input RAMQueueEntry object.
*/
private String getAllocationFailWarningMessage(RAMQueueEntry re) {
if (re != null && re.getData() instanceof HFileBlock) {
HFileContext fileContext = ((HFileBlock) re.getData()).getHFileContext();
String columnFamily = Bytes.toString(fileContext.getColumnFamily());
String tableName = Bytes.toString(fileContext.getTableName());
if (tableName != null && columnFamily != null) {
return ("Most recent failed allocation in " + ALLOCATION_FAIL_LOG_TIME_PERIOD
+ " milliseconds; Table Name = " + tableName + ", Column Family = " + columnFamily
+ ", HFile Name : " + fileContext.getHFileName());
}
}
return ("Most recent failed allocation in " + ALLOCATION_FAIL_LOG_TIME_PERIOD
+ " milliseconds; HFile Name : " + (re == null ? "" : re.getKey()));
}
/**
* Flush the entries in ramCache to IOEngine and add bucket entry to backingMap. Process all that
* are passed in even if failure being sure to remove from ramCache else we'll never undo the
* references and we'll OOME.
* @param entries Presumes list passed in here will be processed by this invocation only. No
* interference expected.
*/
void doDrain(final List entries) throws InterruptedException {
if (entries.isEmpty()) {
return;
}
// This method is a little hard to follow. We run through the passed in entries and for each
// successful add, we add a non-null BucketEntry to the below bucketEntries. Later we must
// do cleanup making sure we've cleared ramCache of all entries regardless of whether we
// successfully added the item to the bucketcache; if we don't do the cleanup, we'll OOME by
// filling ramCache. We do the clean up by again running through the passed in entries
// doing extra work when we find a non-null bucketEntries corresponding entry.
final int size = entries.size();
BucketEntry[] bucketEntries = new BucketEntry[size];
// Index updated inside loop if success or if we can't succeed. We retry if cache is full
// when we go to add an entry by going around the loop again without upping the index.
int index = 0;
while (cacheEnabled && index < size) {
RAMQueueEntry re = null;
try {
re = entries.get(index);
if (re == null) {
LOG.warn("Couldn't get entry or changed on us; who else is messing with it?");
index++;
continue;
}
BucketEntry bucketEntry = re.writeToCache(ioEngine, bucketAllocator, realCacheSize,
this::createRecycler);
// Successfully added. Up index and add bucketEntry. Clear io exceptions.
bucketEntries[index] = bucketEntry;
if (ioErrorStartTime > 0) {
ioErrorStartTime = -1;
}
index++;
} catch (BucketAllocatorException fle) {
long currTs = EnvironmentEdgeManager.currentTime();
cacheStats.allocationFailed(); // Record the warning.
if (allocFailLogPrevTs == 0 || (currTs - allocFailLogPrevTs) > ALLOCATION_FAIL_LOG_TIME_PERIOD) {
LOG.warn (getAllocationFailWarningMessage(re), fle);
allocFailLogPrevTs = currTs;
}
// Presume can't add. Too big? Move index on. Entry will be cleared from ramCache below.
bucketEntries[index] = null;
index++;
} catch (CacheFullException cfe) {
// Cache full when we tried to add. Try freeing space and then retrying (don't up index)
if (!freeInProgress) {
freeSpace("Full!");
} else {
Thread.sleep(50);
}
} catch (IOException ioex) {
// Hopefully transient. Retry. checkIOErrorIsTolerated disables cache if problem.
LOG.error("Failed writing to bucket cache", ioex);
checkIOErrorIsTolerated();
}
}
// Make sure data pages are written on media before we update maps.
try {
ioEngine.sync();
} catch (IOException ioex) {
LOG.error("Failed syncing IO engine", ioex);
checkIOErrorIsTolerated();
// Since we failed sync, free the blocks in bucket allocator
for (int i = 0; i < entries.size(); ++i) {
if (bucketEntries[i] != null) {
bucketAllocator.freeBlock(bucketEntries[i].offset());
bucketEntries[i] = null;
}
}
}
// Now add to backingMap if successfully added to bucket cache. Remove from ramCache if
// success or error.
for (int i = 0; i < size; ++i) {
BlockCacheKey key = entries.get(i).getKey();
// Only add if non-null entry.
if (bucketEntries[i] != null) {
putIntoBackingMap(key, bucketEntries[i]);
}
// Always remove from ramCache even if we failed adding it to the block cache above.
boolean existed = ramCache.remove(key, re -> {
if (re != null) {
heapSize.add(-1 * re.getData().heapSize());
}
});
if (!existed && bucketEntries[i] != null) {
// Block should have already been evicted. Remove it and free space.
final BucketEntry bucketEntry = bucketEntries[i];
bucketEntry.withWriteLock(offsetLock, () -> {
if (backingMap.remove(key, bucketEntry)) {
blockEvicted(key, bucketEntry, false);
}
return null;
});
}
}
long used = bucketAllocator.getUsedSize();
if (used > acceptableSize()) {
freeSpace("Used=" + used + " > acceptable=" + acceptableSize());
}
return;
}
/**
* Blocks until elements available in {@code q} then tries to grab as many as possible before
* returning.
* @param receptacle Where to stash the elements taken from queue. We clear before we use it just
* in case.
* @param q The queue to take from.
* @return {@code receptacle} laden with elements taken from the queue or empty if none found.
*/
static List getRAMQueueEntries(BlockingQueue q,
List receptacle) throws InterruptedException {
// Clear sets all entries to null and sets size to 0. We retain allocations. Presume it
// ok even if list grew to accommodate thousands.
receptacle.clear();
receptacle.add(q.take());
q.drainTo(receptacle);
return receptacle;
}
/**
* @see #retrieveFromFile(int[])
*/
@edu.umd.cs.findbugs.annotations.SuppressWarnings(value="OBL_UNSATISFIED_OBLIGATION",
justification = "false positive, try-with-resources ensures close is called.")
private void persistToFile() throws IOException {
assert !cacheEnabled;
if (!ioEngine.isPersistent()) {
throw new IOException("Attempt to persist non-persistent cache mappings!");
}
try (FileOutputStream fos = new FileOutputStream(persistencePath, false)) {
fos.write(ProtobufMagic.PB_MAGIC);
BucketProtoUtils.toPB(this).writeDelimitedTo(fos);
}
}
/**
* @see #persistToFile()
*/
private void retrieveFromFile(int[] bucketSizes) throws IOException {
File persistenceFile = new File(persistencePath);
if (!persistenceFile.exists()) {
return;
}
assert !cacheEnabled;
try (FileInputStream in = deleteFileOnClose(persistenceFile)) {
int pblen = ProtobufMagic.lengthOfPBMagic();
byte[] pbuf = new byte[pblen];
IOUtils.readFully(in, pbuf, 0, pblen);
if (! ProtobufMagic.isPBMagicPrefix(pbuf)) {
// In 3.0 we have enough flexibility to dump the old cache data.
// TODO: In 2.x line, this might need to be filled in to support reading the old format
throw new IOException("Persistence file does not start with protobuf magic number. " +
persistencePath);
}
parsePB(BucketCacheProtos.BucketCacheEntry.parseDelimitedFrom(in));
bucketAllocator = new BucketAllocator(cacheCapacity, bucketSizes, backingMap, realCacheSize);
blockNumber.add(backingMap.size());
}
}
/**
* Create an input stream that deletes the file after reading it. Use in try-with-resources to
* avoid this pattern where an exception thrown from a finally block may mask earlier exceptions:
*
* File f = ...
* try (FileInputStream fis = new FileInputStream(f)) {
* // use the input stream
* } finally {
* if (!f.delete()) throw new IOException("failed to delete");
* }
*
* @param file the file to read and delete
* @return a FileInputStream for the given file
* @throws IOException if there is a problem creating the stream
*/
private FileInputStream deleteFileOnClose(final File file) throws IOException {
return new FileInputStream(file) {
private File myFile;
private FileInputStream init(File file) {
myFile = file;
return this;
}
@Override
public void close() throws IOException {
// close() will be called during try-with-resources and it will be
// called by finalizer thread during GC. To avoid double-free resource,
// set myFile to null after the first call.
if (myFile == null) {
return;
}
super.close();
if (!myFile.delete()) {
throw new IOException("Failed deleting persistence file " + myFile.getAbsolutePath());
}
myFile = null;
}
}.init(file);
}
private void verifyCapacityAndClasses(long capacitySize, String ioclass, String mapclass)
throws IOException {
if (capacitySize != cacheCapacity) {
throw new IOException("Mismatched cache capacity:"
+ StringUtils.byteDesc(capacitySize) + ", expected: "
+ StringUtils.byteDesc(cacheCapacity));
}
if (!ioEngine.getClass().getName().equals(ioclass)) {
throw new IOException("Class name for IO engine mismatch: " + ioclass
+ ", expected:" + ioEngine.getClass().getName());
}
if (!backingMap.getClass().getName().equals(mapclass)) {
throw new IOException("Class name for cache map mismatch: " + mapclass
+ ", expected:" + backingMap.getClass().getName());
}
}
private void parsePB(BucketCacheProtos.BucketCacheEntry proto) throws IOException {
if (proto.hasChecksum()) {
((PersistentIOEngine) ioEngine).verifyFileIntegrity(proto.getChecksum().toByteArray(),
algorithm);
} else {
// if has not checksum, it means the persistence file is old format
LOG.info("Persistent file is old format, it does not support verifying file integrity!");
}
verifyCapacityAndClasses(proto.getCacheCapacity(), proto.getIoClass(), proto.getMapClass());
backingMap = BucketProtoUtils.fromPB(proto.getDeserializersMap(), proto.getBackingMap(),
this::createRecycler);
}
/**
* Check whether we tolerate IO error this time. If the duration of IOEngine
* throwing errors exceeds ioErrorsDurationTimeTolerated, we will disable the
* cache
*/
private void checkIOErrorIsTolerated() {
long now = EnvironmentEdgeManager.currentTime();
// Do a single read to a local variable to avoid timing issue - HBASE-24454
long ioErrorStartTimeTmp = this.ioErrorStartTime;
if (ioErrorStartTimeTmp > 0) {
if (cacheEnabled && (now - ioErrorStartTimeTmp) > this.ioErrorsTolerationDuration) {
LOG.error("IO errors duration time has exceeded " + ioErrorsTolerationDuration +
"ms, disabling cache, please check your IOEngine");
disableCache();
}
} else {
this.ioErrorStartTime = now;
}
}
/**
* Used to shut down the cache -or- turn it off in the case of something broken.
*/
private void disableCache() {
if (!cacheEnabled) return;
cacheEnabled = false;
ioEngine.shutdown();
this.scheduleThreadPool.shutdown();
for (int i = 0; i < writerThreads.length; ++i) writerThreads[i].interrupt();
this.ramCache.clear();
if (!ioEngine.isPersistent() || persistencePath == null) {
// If persistent ioengine and a path, we will serialize out the backingMap.
this.backingMap.clear();
}
}
private void join() throws InterruptedException {
for (int i = 0; i < writerThreads.length; ++i)
writerThreads[i].join();
}
@Override
public void shutdown() {
disableCache();
LOG.info("Shutdown bucket cache: IO persistent=" + ioEngine.isPersistent()
+ "; path to write=" + persistencePath);
if (ioEngine.isPersistent() && persistencePath != null) {
try {
join();
persistToFile();
} catch (IOException ex) {
LOG.error("Unable to persist data on exit: " + ex.toString(), ex);
} catch (InterruptedException e) {
LOG.warn("Failed to persist data on exit", e);
}
}
}
@Override
public CacheStats getStats() {
return cacheStats;
}
public BucketAllocator getAllocator() {
return this.bucketAllocator;
}
@Override
public long heapSize() {
return this.heapSize.sum();
}
@Override
public long size() {
return this.realCacheSize.sum();
}
@Override
public long getCurrentDataSize() {
return size();
}
@Override
public long getFreeSize() {
return this.bucketAllocator.getFreeSize();
}
@Override
public long getBlockCount() {
return this.blockNumber.sum();
}
@Override
public long getDataBlockCount() {
return getBlockCount();
}
@Override
public long getCurrentSize() {
return this.bucketAllocator.getUsedSize();
}
protected String getAlgorithm() {
return algorithm;
}
/**
* Evicts all blocks for a specific HFile.
*
* This is used for evict-on-close to remove all blocks of a specific HFile.
*
* @return the number of blocks evicted
*/
@Override
public int evictBlocksByHfileName(String hfileName) {
Set keySet = blocksByHFile.subSet(
new BlockCacheKey(hfileName, Long.MIN_VALUE), true,
new BlockCacheKey(hfileName, Long.MAX_VALUE), true);
int numEvicted = 0;
for (BlockCacheKey key : keySet) {
if (evictBlock(key)) {
++numEvicted;
}
}
return numEvicted;
}
/**
* Used to group bucket entries into priority buckets. There will be a
* BucketEntryGroup for each priority (single, multi, memory). Once bucketed,
* the eviction algorithm takes the appropriate number of elements out of each
* according to configuration parameters and their relative sizes.
*/
private class BucketEntryGroup {
private CachedEntryQueue queue;
private long totalSize = 0;
private long bucketSize;
public BucketEntryGroup(long bytesToFree, long blockSize, long bucketSize) {
this.bucketSize = bucketSize;
queue = new CachedEntryQueue(bytesToFree, blockSize);
totalSize = 0;
}
public void add(Map.Entry block) {
totalSize += block.getValue().getLength();
queue.add(block);
}
public long free(long toFree) {
Map.Entry entry;
long freedBytes = 0;
// TODO avoid a cycling siutation. We find no block which is not in use and so no way to free
// What to do then? Caching attempt fail? Need some changes in cacheBlock API?
while ((entry = queue.pollLast()) != null) {
BlockCacheKey blockCacheKey = entry.getKey();
BucketEntry be = entry.getValue();
if (evictBucketEntryIfNoRpcReferenced(blockCacheKey, be)) {
freedBytes += be.getLength();
}
if (freedBytes >= toFree) {
return freedBytes;
}
}
return freedBytes;
}
public long overflow() {
return totalSize - bucketSize;
}
public long totalSize() {
return totalSize;
}
}
/**
* Block Entry stored in the memory with key,data and so on
*/
static class RAMQueueEntry {
private final BlockCacheKey key;
private final Cacheable data;
private long accessCounter;
private boolean inMemory;
RAMQueueEntry(BlockCacheKey bck, Cacheable data, long accessCounter, boolean inMemory) {
this.key = bck;
this.data = data;
this.accessCounter = accessCounter;
this.inMemory = inMemory;
}
public Cacheable getData() {
return data;
}
public BlockCacheKey getKey() {
return key;
}
public void access(long accessCounter) {
this.accessCounter = accessCounter;
}
private ByteBuffAllocator getByteBuffAllocator() {
if (data instanceof HFileBlock) {
return ((HFileBlock) data).getByteBuffAllocator();
}
return ByteBuffAllocator.HEAP;
}
public BucketEntry writeToCache(final IOEngine ioEngine, final BucketAllocator alloc,
final LongAdder realCacheSize, Function createRecycler)
throws IOException {
int len = data.getSerializedLength();
// This cacheable thing can't be serialized
if (len == 0) {
return null;
}
long offset = alloc.allocateBlock(len);
boolean succ = false;
BucketEntry bucketEntry = null;
try {
bucketEntry = new BucketEntry(offset, len, accessCounter, inMemory, createRecycler,
getByteBuffAllocator());
bucketEntry.setDeserializerReference(data.getDeserializer());
if (data instanceof HFileBlock) {
// If an instance of HFileBlock, save on some allocations.
HFileBlock block = (HFileBlock) data;
ByteBuff sliceBuf = block.getBufferReadOnly();
ByteBuffer metadata = block.getMetaData();
ioEngine.write(sliceBuf, offset);
ioEngine.write(metadata, offset + len - metadata.limit());
} else {
// Only used for testing.
ByteBuffer bb = ByteBuffer.allocate(len);
data.serialize(bb, true);
ioEngine.write(bb, offset);
}
succ = true;
} finally {
if (!succ) {
alloc.freeBlock(offset);
}
}
realCacheSize.add(len);
return bucketEntry;
}
}
/**
* Only used in test
* @throws InterruptedException
*/
void stopWriterThreads() throws InterruptedException {
for (WriterThread writerThread : writerThreads) {
writerThread.disableWriter();
writerThread.interrupt();
writerThread.join();
}
}
@Override
public Iterator iterator() {
// Don't bother with ramcache since stuff is in here only a little while.
final Iterator> i =
this.backingMap.entrySet().iterator();
return new Iterator() {
private final long now = System.nanoTime();
@Override
public boolean hasNext() {
return i.hasNext();
}
@Override
public CachedBlock next() {
final Map.Entry e = i.next();
return new CachedBlock() {
@Override
public String toString() {
return BlockCacheUtil.toString(this, now);
}
@Override
public BlockPriority getBlockPriority() {
return e.getValue().getPriority();
}
@Override
public BlockType getBlockType() {
// Not held by BucketEntry. Could add it if wanted on BucketEntry creation.
return null;
}
@Override
public long getOffset() {
return e.getKey().getOffset();
}
@Override
public long getSize() {
return e.getValue().getLength();
}
@Override
public long getCachedTime() {
return e.getValue().getCachedTime();
}
@Override
public String getFilename() {
return e.getKey().getHfileName();
}
@Override
public int compareTo(CachedBlock other) {
int diff = this.getFilename().compareTo(other.getFilename());
if (diff != 0) return diff;
diff = Long.compare(this.getOffset(), other.getOffset());
if (diff != 0) return diff;
if (other.getCachedTime() < 0 || this.getCachedTime() < 0) {
throw new IllegalStateException("" + this.getCachedTime() + ", " +
other.getCachedTime());
}
return Long.compare(other.getCachedTime(), this.getCachedTime());
}
@Override
public int hashCode() {
return e.getKey().hashCode();
}
@Override
public boolean equals(Object obj) {
if (obj instanceof CachedBlock) {
CachedBlock cb = (CachedBlock)obj;
return compareTo(cb) == 0;
} else {
return false;
}
}
};
}
@Override
public void remove() {
throw new UnsupportedOperationException();
}
};
}
@Override
public BlockCache[] getBlockCaches() {
return null;
}
public int getRpcRefCount(BlockCacheKey cacheKey) {
BucketEntry bucketEntry = backingMap.get(cacheKey);
if (bucketEntry != null) {
return bucketEntry.refCnt() - (bucketEntry.markedAsEvicted.get() ? 0 : 1);
}
return 0;
}
float getAcceptableFactor() {
return acceptableFactor;
}
float getMinFactor() {
return minFactor;
}
float getExtraFreeFactor() {
return extraFreeFactor;
}
float getSingleFactor() {
return singleFactor;
}
float getMultiFactor() {
return multiFactor;
}
float getMemoryFactor() {
return memoryFactor;
}
/**
* Wrapped the delegate ConcurrentMap with maintaining its block's reference count.
*/
static class RAMCache {
/**
* Defined the map as {@link ConcurrentHashMap} explicitly here, because in
* {@link RAMCache#get(BlockCacheKey)} and
* {@link RAMCache#putIfAbsent(BlockCacheKey, BucketCache.RAMQueueEntry)} , we need to
* guarantee the atomicity of map#computeIfPresent(key, func) and map#putIfAbsent(key, func).
* Besides, the func method can execute exactly once only when the key is present(or absent)
* and under the lock context. Otherwise, the reference count of block will be messed up.
* Notice that the {@link java.util.concurrent.ConcurrentSkipListMap} can not guarantee that.
*/
final ConcurrentHashMap delegate = new ConcurrentHashMap<>();
public boolean containsKey(BlockCacheKey key) {
return delegate.containsKey(key);
}
public RAMQueueEntry get(BlockCacheKey key) {
return delegate.computeIfPresent(key, (k, re) -> {
// It'll be referenced by RPC, so retain atomically here. if the get and retain is not
// atomic, another thread may remove and release the block, when retaining in this thread we
// may retain a block with refCnt=0 which is disallowed. (see HBASE-22422)
re.getData().retain();
return re;
});
}
/**
* Return the previous associated value, or null if absent. It has the same meaning as
* {@link ConcurrentMap#putIfAbsent(Object, Object)}
*/
public RAMQueueEntry putIfAbsent(BlockCacheKey key, RAMQueueEntry entry) {
AtomicBoolean absent = new AtomicBoolean(false);
RAMQueueEntry re = delegate.computeIfAbsent(key, k -> {
// The RAMCache reference to this entry, so reference count should be increment.
entry.getData().retain();
absent.set(true);
return entry;
});
return absent.get() ? null : re;
}
public boolean remove(BlockCacheKey key) {
return remove(key, re->{});
}
/**
* Defined an {@link Consumer} here, because once the removed entry release its reference count,
* then it's ByteBuffers may be recycled and accessing it outside this method will be thrown an
* exception. the consumer will access entry to remove before release its reference count.
* Notice, don't change its reference count in the {@link Consumer}
*/
public boolean remove(BlockCacheKey key, Consumer action) {
RAMQueueEntry previous = delegate.remove(key);
action.accept(previous);
if (previous != null) {
previous.getData().release();
}
return previous != null;
}
public boolean isEmpty() {
return delegate.isEmpty();
}
public void clear() {
Iterator> it = delegate.entrySet().iterator();
while (it.hasNext()) {
RAMQueueEntry re = it.next().getValue();
it.remove();
re.getData().release();
}
}
}
}