/**
*
* 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;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import java.nio.ByteBuffer;
import java.util.Collection;
import java.util.Map;
import java.util.Random;
import org.apache.hadoop.hbase.HBaseTestingUtility;
import org.apache.hadoop.hbase.SmallTests;
import org.apache.hadoop.hbase.io.HeapSize;
import org.apache.hadoop.hbase.io.hfile.LruBlockCache.EvictionThread;
import org.apache.hadoop.hbase.util.ClassSize;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;
import org.junit.runners.Parameterized.Parameters;
/**
* Tests the concurrent LruBlockCache.<p>
*
* Tests will ensure it grows and shrinks in size properly,
* evictions run when they're supposed to and do what they should,
* and that cached blocks are accessible when expected to be.
*/
@Category(SmallTests.class)
public class TestLruBlockCache {
@Test
public void testBackgroundEvictionThread() throws Exception {
long maxSize = 100000;
long blockSize = calculateBlockSizeDefault(maxSize, 9); // room for 9, will evict
LruBlockCache cache = new LruBlockCache(maxSize,blockSize);
CachedItem [] blocks = generateFixedBlocks(10, blockSize, "block");
EvictionThread evictionThread = cache.getEvictionThread();
assertTrue(evictionThread != null);
// Make sure eviction thread has entered run method
while (!evictionThread.isEnteringRun()) {
Thread.sleep(1);
}
// Add all the blocks
for (CachedItem block : blocks) {
cache.cacheBlock(block.cacheKey, block);
}
// Let the eviction run
int n = 0;
while(cache.getEvictionCount() == 0) {
Thread.sleep(200);
assertTrue(n++ < 20);
}
System.out.println("Background Evictions run: " + cache.getEvictionCount());
// A single eviction run should have occurred
assertEquals(cache.getEvictionCount(), 1);
}
@Test
public void testCacheSimple() throws Exception {
long maxSize = 1000000;
long blockSize = calculateBlockSizeDefault(maxSize, 101);
LruBlockCache cache = new LruBlockCache(maxSize, blockSize);
CachedItem [] blocks = generateRandomBlocks(100, blockSize);
long expectedCacheSize = cache.heapSize();
// Confirm empty
for (CachedItem block : blocks) {
assertTrue(cache.getBlock(block.cacheKey, true, false) == null);
}
// Add blocks
for (CachedItem block : blocks) {
cache.cacheBlock(block.cacheKey, block);
expectedCacheSize += block.cacheBlockHeapSize();
}
// Verify correctly calculated cache heap size
assertEquals(expectedCacheSize, cache.heapSize());
// Check if all blocks are properly cached and retrieved
for (CachedItem block : blocks) {
HeapSize buf = cache.getBlock(block.cacheKey, true, false);
assertTrue(buf != null);
assertEquals(buf.heapSize(), block.heapSize());
}
// Re-add same blocks and ensure nothing has changed
for (CachedItem block : blocks) {
try {
cache.cacheBlock(block.cacheKey, block);
assertTrue("Cache should not allow re-caching a block", false);
} catch(RuntimeException re) {
// expected
}
}
// Verify correctly calculated cache heap size
assertEquals(expectedCacheSize, cache.heapSize());
// Check if all blocks are properly cached and retrieved
for (CachedItem block : blocks) {
HeapSize buf = cache.getBlock(block.cacheKey, true, false);
assertTrue(buf != null);
assertEquals(buf.heapSize(), block.heapSize());
}
// Expect no evictions
assertEquals(0, cache.getEvictionCount());
Thread t = new LruBlockCache.StatisticsThread(cache);
t.start();
t.join();
}
@Test
public void testCacheEvictionSimple() throws Exception {
long maxSize = 100000;
long blockSize = calculateBlockSizeDefault(maxSize, 10);
LruBlockCache cache = new LruBlockCache(maxSize,blockSize,false);
CachedItem [] blocks = generateFixedBlocks(10, blockSize, "block");
long expectedCacheSize = cache.heapSize();
// Add all the blocks
for (CachedItem block : blocks) {
cache.cacheBlock(block.cacheKey, block);
expectedCacheSize += block.cacheBlockHeapSize();
}
// A single eviction run should have occurred
assertEquals(1, cache.getEvictionCount());
// Our expected size overruns acceptable limit
assertTrue(expectedCacheSize >
(maxSize * LruBlockCache.DEFAULT_ACCEPTABLE_FACTOR));
// But the cache did not grow beyond max
assertTrue(cache.heapSize() < maxSize);
// And is still below the acceptable limit
assertTrue(cache.heapSize() <
(maxSize * LruBlockCache.DEFAULT_ACCEPTABLE_FACTOR));
// All blocks except block 0 should be in the cache
assertTrue(cache.getBlock(blocks[0].cacheKey, true, false) == null);
for(int i=1;i<blocks.length;i++) {
assertEquals(cache.getBlock(blocks[i].cacheKey, true, false),
blocks[i]);
}
}
@Test
public void testCacheEvictionTwoPriorities() throws Exception {
long maxSize = 100000;
long blockSize = calculateBlockSizeDefault(maxSize, 10);
LruBlockCache cache = new LruBlockCache(maxSize,blockSize,false);
CachedItem [] singleBlocks = generateFixedBlocks(5, 10000, "single");
CachedItem [] multiBlocks = generateFixedBlocks(5, 10000, "multi");
long expectedCacheSize = cache.heapSize();
// Add and get the multi blocks
for (CachedItem block : multiBlocks) {
cache.cacheBlock(block.cacheKey, block);
expectedCacheSize += block.cacheBlockHeapSize();
assertEquals(cache.getBlock(block.cacheKey, true, false), block);
}
// Add the single blocks (no get)
for (CachedItem block : singleBlocks) {
cache.cacheBlock(block.cacheKey, block);
expectedCacheSize += block.heapSize();
}
// A single eviction run should have occurred
assertEquals(cache.getEvictionCount(), 1);
// We expect two entries evicted
assertEquals(cache.getEvictedCount(), 2);
// Our expected size overruns acceptable limit
assertTrue(expectedCacheSize >
(maxSize * LruBlockCache.DEFAULT_ACCEPTABLE_FACTOR));
// But the cache did not grow beyond max
assertTrue(cache.heapSize() <= maxSize);
// And is now below the acceptable limit
assertTrue(cache.heapSize() <=
(maxSize * LruBlockCache.DEFAULT_ACCEPTABLE_FACTOR));
// We expect fairness across the two priorities.
// This test makes multi go barely over its limit, in-memory
// empty, and the rest in single. Two single evictions and
// one multi eviction expected.
assertTrue(cache.getBlock(singleBlocks[0].cacheKey, true, false) == null);
assertTrue(cache.getBlock(multiBlocks[0].cacheKey, true, false) == null);
// And all others to be cached
for(int i=1;i<4;i++) {
assertEquals(cache.getBlock(singleBlocks[i].cacheKey, true, false),
singleBlocks[i]);
assertEquals(cache.getBlock(multiBlocks[i].cacheKey, true, false),
multiBlocks[i]);
}
}
@Test
public void testCacheEvictionThreePriorities() throws Exception {
long maxSize = 100000;
long blockSize = calculateBlockSize(maxSize, 10);
LruBlockCache cache = new LruBlockCache(maxSize, blockSize, false,
(int)Math.ceil(1.2*maxSize/blockSize),
LruBlockCache.DEFAULT_LOAD_FACTOR,
LruBlockCache.DEFAULT_CONCURRENCY_LEVEL,
0.98f, // min
0.99f, // acceptable
0.33f, // single
0.33f, // multi
0.34f);// memory
CachedItem [] singleBlocks = generateFixedBlocks(5, blockSize, "single");
CachedItem [] multiBlocks = generateFixedBlocks(5, blockSize, "multi");
CachedItem [] memoryBlocks = generateFixedBlocks(5, blockSize, "memory");
long expectedCacheSize = cache.heapSize();
// Add 3 blocks from each priority
for(int i=0;i<3;i++) {
// Just add single blocks
cache.cacheBlock(singleBlocks[i].cacheKey, singleBlocks[i]);
expectedCacheSize += singleBlocks[i].cacheBlockHeapSize();
// Add and get multi blocks
cache.cacheBlock(multiBlocks[i].cacheKey, multiBlocks[i]);
expectedCacheSize += multiBlocks[i].cacheBlockHeapSize();
cache.getBlock(multiBlocks[i].cacheKey, true, false);
// Add memory blocks as such
cache.cacheBlock(memoryBlocks[i].cacheKey, memoryBlocks[i], true);
expectedCacheSize += memoryBlocks[i].cacheBlockHeapSize();
}
// Do not expect any evictions yet
assertEquals(0, cache.getEvictionCount());
// Verify cache size
assertEquals(expectedCacheSize, cache.heapSize());
// Insert a single block, oldest single should be evicted
cache.cacheBlock(singleBlocks[3].cacheKey, singleBlocks[3]);
// Single eviction, one thing evicted
assertEquals(1, cache.getEvictionCount());
assertEquals(1, cache.getEvictedCount());
// Verify oldest single block is the one evicted
assertEquals(null, cache.getBlock(singleBlocks[0].cacheKey, true, false));
// Change the oldest remaining single block to a multi
cache.getBlock(singleBlocks[1].cacheKey, true, false);
// Insert another single block
cache.cacheBlock(singleBlocks[4].cacheKey, singleBlocks[4]);
// Two evictions, two evicted.
assertEquals(2, cache.getEvictionCount());
assertEquals(2, cache.getEvictedCount());
// Oldest multi block should be evicted now
assertEquals(null, cache.getBlock(multiBlocks[0].cacheKey, true, false));
// Insert another memory block
cache.cacheBlock(memoryBlocks[3].cacheKey, memoryBlocks[3], true);
// Three evictions, three evicted.
assertEquals(3, cache.getEvictionCount());
assertEquals(3, cache.getEvictedCount());
// Oldest memory block should be evicted now
assertEquals(null, cache.getBlock(memoryBlocks[0].cacheKey, true, false));
// Add a block that is twice as big (should force two evictions)
CachedItem [] bigBlocks = generateFixedBlocks(3, blockSize*3, "big");
cache.cacheBlock(bigBlocks[0].cacheKey, bigBlocks[0]);
// Four evictions, six evicted (inserted block 3X size, expect +3 evicted)
assertEquals(4, cache.getEvictionCount());
assertEquals(6, cache.getEvictedCount());
// Expect three remaining singles to be evicted
assertEquals(null, cache.getBlock(singleBlocks[2].cacheKey, true, false));
assertEquals(null, cache.getBlock(singleBlocks[3].cacheKey, true, false));
assertEquals(null, cache.getBlock(singleBlocks[4].cacheKey, true, false));
// Make the big block a multi block
cache.getBlock(bigBlocks[0].cacheKey, true, false);
// Cache another single big block
cache.cacheBlock(bigBlocks[1].cacheKey, bigBlocks[1]);
// Five evictions, nine evicted (3 new)
assertEquals(5, cache.getEvictionCount());
assertEquals(9, cache.getEvictedCount());
// Expect three remaining multis to be evicted
assertEquals(null, cache.getBlock(singleBlocks[1].cacheKey, true, false));
assertEquals(null, cache.getBlock(multiBlocks[1].cacheKey, true, false));
assertEquals(null, cache.getBlock(multiBlocks[2].cacheKey, true, false));
// Cache a big memory block
cache.cacheBlock(bigBlocks[2].cacheKey, bigBlocks[2], true);
// Six evictions, twelve evicted (3 new)
assertEquals(6, cache.getEvictionCount());
assertEquals(12, cache.getEvictedCount());
// Expect three remaining in-memory to be evicted
assertEquals(null, cache.getBlock(memoryBlocks[1].cacheKey, true, false));
assertEquals(null, cache.getBlock(memoryBlocks[2].cacheKey, true, false));
assertEquals(null, cache.getBlock(memoryBlocks[3].cacheKey, true, false));
}
// test scan resistance
@Test
public void testScanResistance() throws Exception {
long maxSize = 100000;
long blockSize = calculateBlockSize(maxSize, 10);
LruBlockCache cache = new LruBlockCache(maxSize, blockSize, false,
(int)Math.ceil(1.2*maxSize/blockSize),
LruBlockCache.DEFAULT_LOAD_FACTOR,
LruBlockCache.DEFAULT_CONCURRENCY_LEVEL,
0.66f, // min
0.99f, // acceptable
0.33f, // single
0.33f, // multi
0.34f);// memory
CachedItem [] singleBlocks = generateFixedBlocks(20, blockSize, "single");
CachedItem [] multiBlocks = generateFixedBlocks(5, blockSize, "multi");
// Add 5 multi blocks
for (CachedItem block : multiBlocks) {
cache.cacheBlock(block.cacheKey, block);
cache.getBlock(block.cacheKey, true, false);
}
// Add 5 single blocks
for(int i=0;i<5;i++) {
cache.cacheBlock(singleBlocks[i].cacheKey, singleBlocks[i]);
}
// An eviction ran
assertEquals(1, cache.getEvictionCount());
// To drop down to 2/3 capacity, we'll need to evict 4 blocks
assertEquals(4, cache.getEvictedCount());
// Should have been taken off equally from single and multi
assertEquals(null, cache.getBlock(singleBlocks[0].cacheKey, true, false));
assertEquals(null, cache.getBlock(singleBlocks[1].cacheKey, true, false));
assertEquals(null, cache.getBlock(multiBlocks[0].cacheKey, true, false));
assertEquals(null, cache.getBlock(multiBlocks[1].cacheKey, true, false));
// Let's keep "scanning" by adding single blocks. From here on we only
// expect evictions from the single bucket.
// Every time we reach 10 total blocks (every 4 inserts) we get 4 single
// blocks evicted. Inserting 13 blocks should yield 3 more evictions and
// 12 more evicted.
for(int i=5;i<18;i++) {
cache.cacheBlock(singleBlocks[i].cacheKey, singleBlocks[i]);
}
// 4 total evictions, 16 total evicted
assertEquals(4, cache.getEvictionCount());
assertEquals(16, cache.getEvictedCount());
// Should now have 7 total blocks
assertEquals(7, cache.size());
}
// test setMaxSize
@Test
public void testResizeBlockCache() throws Exception {
long maxSize = 300000;
long blockSize = calculateBlockSize(maxSize, 31);
LruBlockCache cache = new LruBlockCache(maxSize, blockSize, false,
(int)Math.ceil(1.2*maxSize/blockSize),
LruBlockCache.DEFAULT_LOAD_FACTOR,
LruBlockCache.DEFAULT_CONCURRENCY_LEVEL,
0.98f, // min
0.99f, // acceptable
0.33f, // single
0.33f, // multi
0.34f);// memory
CachedItem [] singleBlocks = generateFixedBlocks(10, blockSize, "single");
CachedItem [] multiBlocks = generateFixedBlocks(10, blockSize, "multi");
CachedItem [] memoryBlocks = generateFixedBlocks(10, blockSize, "memory");
// Add all blocks from all priorities
for(int i=0;i<10;i++) {
// Just add single blocks
cache.cacheBlock(singleBlocks[i].cacheKey, singleBlocks[i]);
// Add and get multi blocks
cache.cacheBlock(multiBlocks[i].cacheKey, multiBlocks[i]);
cache.getBlock(multiBlocks[i].cacheKey, true, false);
// Add memory blocks as such
cache.cacheBlock(memoryBlocks[i].cacheKey, memoryBlocks[i], true);
}
// Do not expect any evictions yet
assertEquals(0, cache.getEvictionCount());
// Resize to half capacity plus an extra block (otherwise we evict an extra)
cache.setMaxSize((long)(maxSize * 0.5f));
// Should have run a single eviction
assertEquals(1, cache.getEvictionCount());
// And we expect 1/2 of the blocks to be evicted
assertEquals(15, cache.getEvictedCount());
// And the oldest 5 blocks from each category should be gone
for(int i=0;i<5;i++) {
assertEquals(null, cache.getBlock(singleBlocks[i].cacheKey, true, false));
assertEquals(null, cache.getBlock(multiBlocks[i].cacheKey, true, false));
assertEquals(null, cache.getBlock(memoryBlocks[i].cacheKey, true, false));
}
// And the newest 5 blocks should still be accessible
for(int i=5;i<10;i++) {
assertEquals(singleBlocks[i], cache.getBlock(singleBlocks[i].cacheKey, true, false));
assertEquals(multiBlocks[i], cache.getBlock(multiBlocks[i].cacheKey, true, false));
assertEquals(memoryBlocks[i], cache.getBlock(memoryBlocks[i].cacheKey, true, false));
}
}
// test metricsPastNPeriods
@Test
public void testPastNPeriodsMetrics() throws Exception {
double delta = 0.01;
// 3 total periods
CacheStats stats = new CacheStats(3);
// No accesses, should be 0
stats.rollMetricsPeriod();
assertEquals(0.0, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.0, stats.getHitCachingRatioPastNPeriods(), delta);
// period 1, 1 hit caching, 1 hit non-caching, 2 miss non-caching
// should be (2/4)=0.5 and (1/1)=1
stats.hit(false);
stats.hit(true);
stats.miss(false);
stats.miss(false);
stats.rollMetricsPeriod();
assertEquals(0.5, stats.getHitRatioPastNPeriods(), delta);
assertEquals(1.0, stats.getHitCachingRatioPastNPeriods(), delta);
// period 2, 1 miss caching, 3 miss non-caching
// should be (2/8)=0.25 and (1/2)=0.5
stats.miss(true);
stats.miss(false);
stats.miss(false);
stats.miss(false);
stats.rollMetricsPeriod();
assertEquals(0.25, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.5, stats.getHitCachingRatioPastNPeriods(), delta);
// period 3, 2 hits of each type
// should be (6/12)=0.5 and (3/4)=0.75
stats.hit(false);
stats.hit(true);
stats.hit(false);
stats.hit(true);
stats.rollMetricsPeriod();
assertEquals(0.5, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.75, stats.getHitCachingRatioPastNPeriods(), delta);
// period 4, evict period 1, two caching misses
// should be (4/10)=0.4 and (2/5)=0.4
stats.miss(true);
stats.miss(true);
stats.rollMetricsPeriod();
assertEquals(0.4, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.4, stats.getHitCachingRatioPastNPeriods(), delta);
// period 5, evict period 2, 2 caching misses, 2 non-caching hit
// should be (6/10)=0.6 and (2/6)=1/3
stats.miss(true);
stats.miss(true);
stats.hit(false);
stats.hit(false);
stats.rollMetricsPeriod();
assertEquals(0.6, stats.getHitRatioPastNPeriods(), delta);
assertEquals((double)1/3, stats.getHitCachingRatioPastNPeriods(), delta);
// period 6, evict period 3
// should be (2/6)=1/3 and (0/4)=0
stats.rollMetricsPeriod();
assertEquals((double)1/3, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.0, stats.getHitCachingRatioPastNPeriods(), delta);
// period 7, evict period 4
// should be (2/4)=0.5 and (0/2)=0
stats.rollMetricsPeriod();
assertEquals(0.5, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.0, stats.getHitCachingRatioPastNPeriods(), delta);
// period 8, evict period 5
// should be 0 and 0
stats.rollMetricsPeriod();
assertEquals(0.0, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.0, stats.getHitCachingRatioPastNPeriods(), delta);
// period 9, one of each
// should be (2/4)=0.5 and (1/2)=0.5
stats.miss(true);
stats.miss(false);
stats.hit(true);
stats.hit(false);
stats.rollMetricsPeriod();
assertEquals(0.5, stats.getHitRatioPastNPeriods(), delta);
assertEquals(0.5, stats.getHitCachingRatioPastNPeriods(), delta);
}
private CachedItem [] generateFixedBlocks(int numBlocks, int size, String pfx) {
CachedItem [] blocks = new CachedItem[numBlocks];
for(int i=0;i<numBlocks;i++) {
blocks[i] = new CachedItem(pfx + i, size);
}
return blocks;
}
private CachedItem [] generateFixedBlocks(int numBlocks, long size, String pfx) {
return generateFixedBlocks(numBlocks, (int)size, pfx);
}
private CachedItem [] generateRandomBlocks(int numBlocks, long maxSize) {
CachedItem [] blocks = new CachedItem[numBlocks];
Random r = new Random();
for(int i=0;i<numBlocks;i++) {
blocks[i] = new CachedItem("block" + i, r.nextInt((int)maxSize)+1);
}
return blocks;
}
private long calculateBlockSize(long maxSize, int numBlocks) {
long roughBlockSize = maxSize / numBlocks;
int numEntries = (int)Math.ceil((1.2)*maxSize/roughBlockSize);
long totalOverhead = LruBlockCache.CACHE_FIXED_OVERHEAD +
ClassSize.CONCURRENT_HASHMAP +
(numEntries * ClassSize.CONCURRENT_HASHMAP_ENTRY) +
(LruBlockCache.DEFAULT_CONCURRENCY_LEVEL * ClassSize.CONCURRENT_HASHMAP_SEGMENT);
long negateBlockSize = (long)(totalOverhead/numEntries);
negateBlockSize += CachedBlock.PER_BLOCK_OVERHEAD;
return ClassSize.align((long)Math.floor((roughBlockSize - negateBlockSize)*0.99f));
}
private long calculateBlockSizeDefault(long maxSize, int numBlocks) {
long roughBlockSize = maxSize / numBlocks;
int numEntries = (int)Math.ceil((1.2)*maxSize/roughBlockSize);
long totalOverhead = LruBlockCache.CACHE_FIXED_OVERHEAD +
ClassSize.CONCURRENT_HASHMAP +
(numEntries * ClassSize.CONCURRENT_HASHMAP_ENTRY) +
(LruBlockCache.DEFAULT_CONCURRENCY_LEVEL * ClassSize.CONCURRENT_HASHMAP_SEGMENT);
long negateBlockSize = totalOverhead / numEntries;
negateBlockSize += CachedBlock.PER_BLOCK_OVERHEAD;
return ClassSize.align((long)Math.floor((roughBlockSize - negateBlockSize)*
LruBlockCache.DEFAULT_ACCEPTABLE_FACTOR));
}
private static class CachedItem implements Cacheable {
BlockCacheKey cacheKey;
int size;
CachedItem(String blockName, int size) {
this.cacheKey = new BlockCacheKey(blockName, 0);
this.size = size;
}
/** The size of this item reported to the block cache layer */
@Override
public long heapSize() {
return ClassSize.align(size);
}
/** Size of the cache block holding this item. Used for verification. */
public long cacheBlockHeapSize() {
return CachedBlock.PER_BLOCK_OVERHEAD
+ ClassSize.align(cacheKey.heapSize())
+ ClassSize.align(size);
}
@Override
public int getSerializedLength() {
return 0;
}
@Override
public CacheableDeserializer<Cacheable> getDeserializer() {
return null;
}
@Override
public void serialize(ByteBuffer destination) {
}
@Override
public BlockType getBlockType() {
return BlockType.DATA;
}
}
}