| public GetPercentile ( double percentile ) : int | ||
| percentile | double | Value such as 99 (99th percentile), 99.5 (99.5th percentile), 50 (median, 50th percentile) to compute and retrieve percentile from rolling buckets. |
| return | int | |
public void RollingPercentile_ValueIsZeroAfterRollingWindowPassesAndNoTraffic()
{
MockedTime time = new MockedTime();
HystrixRollingPercentile p = new HystrixRollingPercentile(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, enabled);
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(2000);
p.AddValue(4000);
Assert.AreEqual(1, p.Buckets.Size);
// no bucket turnover yet so percentile not yet generated
Assert.AreEqual(0, p.GetPercentile(50));
time.Increment(6000);
// still only 1 bucket until we touch it again
Assert.AreEqual(1, p.Buckets.Size);
// a bucket has been created so we have a new percentile
Assert.AreEqual(1500, p.GetPercentile(50));
// let 1 minute pass
time.Increment(60000);
// no data in a minute should mean all buckets are empty (or reset) so we should not have any percentiles
Assert.AreEqual(0, p.GetPercentile(50));
}
public void RollingPercentile_DoesNothingWhenDisabled()
{
MockedTime time = new MockedTime();
int previousTime = 0;
HystrixRollingPercentile p = new HystrixRollingPercentile(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, HystrixPropertyFactory.AsProperty(false));
int length = SampleData2.GetLength(0);
for (int i = 0; i < length; i++)
{
int timeInMillisecondsSinceStart = SampleData2[i, 0];
int latency = SampleData2[i, 1];
time.Increment(timeInMillisecondsSinceStart - previousTime);
previousTime = timeInMillisecondsSinceStart;
p.AddValue(latency);
}
Assert.AreEqual(-1, p.GetPercentile(50));
Assert.AreEqual(-1, p.GetPercentile(75));
Assert.AreEqual(-1, p.GetMean());
}
public void RollingPercentile_SampleDataOverTime2()
{
TestContext.WriteLine("\n\n***************************** testSampleDataOverTime2 \n");
MockedTime time = new MockedTime();
int previousTime = 0;
HystrixRollingPercentile p = new HystrixRollingPercentile(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, enabled);
int length = SampleData2.GetLength(0);
for (int i = 0; i < length; i++)
{
int timeInMillisecondsSinceStart = SampleData2[i, 0];
int latency = SampleData2[i, 1];
time.Increment(timeInMillisecondsSinceStart - previousTime);
previousTime = timeInMillisecondsSinceStart;
p.AddValue(latency);
}
TestContext.WriteLine("0.01: " + p.GetPercentile(0.01));
TestContext.WriteLine("Median: " + p.GetPercentile(50));
TestContext.WriteLine("90th: " + p.GetPercentile(90));
TestContext.WriteLine("99th: " + p.GetPercentile(99));
TestContext.WriteLine("99.5th: " + p.GetPercentile(99.5));
TestContext.WriteLine("99.99: " + p.GetPercentile(99.99));
if (p.GetPercentile(50) > 90 || p.GetPercentile(50) < 50)
{
Assert.Fail("We expect around 60-70 but got: " + p.GetPercentile(50));
}
if (p.GetPercentile(99) < 400)
{
Assert.Fail("We expect to see some high values over 400 but got: " + p.GetPercentile(99));
}
}
public void RollingPercentile_Rolling()
{
MockedTime time = new MockedTime();
HystrixRollingPercentile p = new HystrixRollingPercentile(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, enabled);
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(1000);
p.AddValue(2000);
Assert.AreEqual(1, p.Buckets.Size);
// no bucket turnover yet so percentile not yet generated
Assert.AreEqual(0, p.GetPercentile(50));
time.Increment(6000);
// still only 1 bucket until we touch it again
Assert.AreEqual(1, p.Buckets.Size);
// a bucket has been created so we have a new percentile
Assert.AreEqual(1000, p.GetPercentile(50));
// now 2 buckets since getting a percentile causes bucket retrieval
Assert.AreEqual(2, p.Buckets.Size);
p.AddValue(1000);
p.AddValue(500);
// should still be 2 buckets
Assert.AreEqual(2, p.Buckets.Size);
p.AddValue(200);
p.AddValue(200);
p.AddValue(1600);
p.AddValue(200);
p.AddValue(1600);
p.AddValue(1600);
// we haven't progressed to a new bucket so the percentile should be the same and ignore the most recent bucket
Assert.AreEqual(1000, p.GetPercentile(50));
// increment to another bucket so we include all of the above in the PercentileSnapshot
time.Increment(6000);
// the rolling version should have the same data as creating a snapshot like this
HystrixRollingPercentile.PercentileSnapshot ps = new HystrixRollingPercentile.PercentileSnapshot(1000, 1000, 1000, 2000, 1000, 500, 200, 200, 1600, 200, 1600, 1600);
Assert.AreEqual(ps.GetPercentile(0.15), p.GetPercentile(0.15));
Assert.AreEqual(ps.GetPercentile(0.50), p.GetPercentile(0.50));
Assert.AreEqual(ps.GetPercentile(0.90), p.GetPercentile(0.90));
Assert.AreEqual(ps.GetPercentile(0.995), p.GetPercentile(0.995));
TestContext.WriteLine("100th: " + ps.GetPercentile(100) + " " + p.GetPercentile(100));
TestContext.WriteLine("99.5th: " + ps.GetPercentile(99.5) + " " + p.GetPercentile(99.5));
TestContext.WriteLine("99th: " + ps.GetPercentile(99) + " " + p.GetPercentile(99));
TestContext.WriteLine("90th: " + ps.GetPercentile(90) + " " + p.GetPercentile(90));
TestContext.WriteLine("50th: " + ps.GetPercentile(50) + " " + p.GetPercentile(50));
TestContext.WriteLine("10th: " + ps.GetPercentile(10) + " " + p.GetPercentile(10));
// mean = 1000+1000+1000+2000+1000+500+200+200+1600+200+1600+1600/12
Assert.AreEqual(991, ps.Mean);
}
public void RollingPercentile_SampleDataOverTime1()
{
TestContext.WriteLine("\n\n***************************** testSampleDataOverTime1 \n");
MockedTime time = new MockedTime();
HystrixRollingPercentile p = new HystrixRollingPercentile(time, timeInMilliseconds, numberOfBuckets, bucketDataLength, enabled);
int previousTime = 0;
int length = SampleData1.GetLength(0);
for (int i = 0; i < length; i++)
{
int timeInMillisecondsSinceStart = SampleData1[i, 0];
int latency = SampleData1[i, 1];
time.Increment(timeInMillisecondsSinceStart - previousTime);
previousTime = timeInMillisecondsSinceStart;
p.AddValue(latency);
}
TestContext.WriteLine("0.01: " + p.GetPercentile(0.01));
TestContext.WriteLine("Median: " + p.GetPercentile(50));
TestContext.WriteLine("90th: " + p.GetPercentile(90));
TestContext.WriteLine("99th: " + p.GetPercentile(99));
TestContext.WriteLine("99.5th: " + p.GetPercentile(99.5));
TestContext.WriteLine("99.99: " + p.GetPercentile(99.99));
TestContext.WriteLine("Median: " + p.GetPercentile(50));
TestContext.WriteLine("Median: " + p.GetPercentile(50));
TestContext.WriteLine("Median: " + p.GetPercentile(50));
/*
* In a loop as a use case was found where very different values were calculated in subsequent requests.
*/
for (int i = 0; i < 10; i++)
{
if (p.GetPercentile(50) > 5)
{
Assert.Fail("We expect around 2 but got: " + p.GetPercentile(50));
}
if (p.GetPercentile(99.5) < 20)
{
Assert.Fail("We expect to see some high values over 20 but got: " + p.GetPercentile(99.5));
}
}
}