@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);
}
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);
}
}
}
/** 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);
}
}
@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());
}
