| package org.apache.cassandra.utils; |
| |
| import java.util.List; |
| import java.util.Map; |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| import java.util.concurrent.atomic.AtomicBoolean; |
| |
| import com.google.common.collect.Maps; |
| import com.google.common.util.concurrent.Uninterruptibles; |
| import org.junit.Test; |
| |
| import com.clearspring.analytics.hash.MurmurHash; |
| import com.clearspring.analytics.stream.Counter; |
| import junit.framework.Assert; |
| import org.apache.cassandra.utils.TopKSampler.SamplerResult; |
| |
| public class TopKSamplerTest |
| { |
| |
| @Test |
| public void testSamplerSingleInsertionsEqualMulti() throws TimeoutException |
| { |
| TopKSampler<String> sampler = new TopKSampler<String>(); |
| sampler.beginSampling(10); |
| insert(sampler); |
| waitForEmpty(1000); |
| SamplerResult single = sampler.finishSampling(10); |
| |
| TopKSampler<String> sampler2 = new TopKSampler<String>(); |
| sampler2.beginSampling(10); |
| for(int i = 1; i <= 10; i++) |
| { |
| String key = "item" + i; |
| sampler2.addSample(key, MurmurHash.hash64(key), i); |
| } |
| waitForEmpty(1000); |
| Assert.assertEquals(countMap(single.topK), countMap(sampler2.finishSampling(10).topK)); |
| Assert.assertEquals(sampler2.hll.cardinality(), 10); |
| Assert.assertEquals(sampler.hll.cardinality(), sampler2.hll.cardinality()); |
| } |
| |
| @Test |
| public void testSamplerOutOfOrder() throws TimeoutException |
| { |
| TopKSampler<String> sampler = new TopKSampler<String>(); |
| sampler.beginSampling(10); |
| insert(sampler); |
| waitForEmpty(1000); |
| SamplerResult single = sampler.finishSampling(10); |
| single = sampler.finishSampling(10); |
| } |
| |
| /** |
| * checking for exceptions from SS/HLL which are not thread safe |
| */ |
| @Test |
| public void testMultithreadedAccess() throws Exception |
| { |
| final AtomicBoolean running = new AtomicBoolean(true); |
| final CountDownLatch latch = new CountDownLatch(1); |
| final TopKSampler<String> sampler = new TopKSampler<String>(); |
| |
| new Thread(new Runnable() |
| { |
| public void run() |
| { |
| try |
| { |
| while (running.get()) |
| { |
| insert(sampler); |
| } |
| } finally |
| { |
| latch.countDown(); |
| } |
| } |
| |
| } |
| ,"inserter").start(); |
| try |
| { |
| // start/stop in fast iterations |
| for(int i = 0; i<100; i++) |
| { |
| sampler.beginSampling(i); |
| sampler.finishSampling(i); |
| } |
| // start/stop with pause to let it build up past capacity |
| for(int i = 0; i<3; i++) |
| { |
| sampler.beginSampling(i); |
| Thread.sleep(250); |
| sampler.finishSampling(i); |
| } |
| |
| // with empty results |
| running.set(false); |
| latch.await(1, TimeUnit.SECONDS); |
| waitForEmpty(1000); |
| for(int i = 0; i<10; i++) |
| { |
| sampler.beginSampling(i); |
| Thread.sleep(i); |
| sampler.finishSampling(i); |
| } |
| } finally |
| { |
| running.set(false); |
| } |
| } |
| |
| private void insert(TopKSampler<String> sampler) |
| { |
| for(int i = 1; i <= 10; i++) |
| { |
| for(int j = 0; j < i; j++) |
| { |
| String key = "item" + i; |
| sampler.addSample(key, MurmurHash.hash64(key), 1); |
| } |
| } |
| } |
| |
| private void waitForEmpty(int timeoutMs) throws TimeoutException |
| { |
| int timeout = 0; |
| while (!TopKSampler.samplerExecutor.getQueue().isEmpty()) |
| { |
| timeout++; |
| Uninterruptibles.sleepUninterruptibly(100, TimeUnit.MILLISECONDS); |
| if (timeout * 100 > timeoutMs) |
| { |
| throw new TimeoutException("TRACE executor not cleared within timeout"); |
| } |
| } |
| } |
| |
| private <T> Map<T, Long> countMap(List<Counter<T>> target) |
| { |
| Map<T, Long> counts = Maps.newHashMap(); |
| for(Counter<T> counter : target) |
| { |
| counts.put(counter.getItem(), counter.getCount()); |
| } |
| return counts; |
| } |
| } |