Package com.linkedin.venice.reliability

Class LoadController

java.lang.Object
com.linkedin.venice.reliability.LoadController
public class LoadController extends Object
The LoadController is used to control the load on a server by tracking the request and accept rates, and it borrows the idea from here: https://sre.google/sre-book/handling-overload/ High-level idea: 1. The load controller will track every request. 2. For the request, which meets the expectation, it will mark it as accepted. 3. It uses the following formula to calculate the rejection ratio: max(0, (requestRate - acceptMultiplier * acceptRate) / (requestRate + 1)) Here is how the rejection ratio calculation being implemented here: 1. This class is using a sliding window to calcuate the request rate and accept rate. 2. The window size is controlled by windowSizeInSec. 3. To reduce the overhead of calculating the rejection ratio, we only calculate it every rejectionRatioUpdateIntervalInSec. 4. This class also limits the maximum rejection ratio to maxRejectionRatio to avoid rejecting every request, otherwise, the backend won't be able to recover automatically. 5. We can tune acceptMultiplier to control the rejection ratio.

  • Method Details

    • recordRequest

      public void recordRequest()

    • recordAccept

      public void recordAccept()

    • getRejectionRatio

      public double getRejectionRatio()

    • isOverloaded

      public boolean isOverloaded()

    • shouldRejectRequest

      public boolean shouldRejectRequest()

    • newBuilder

      public static LoadController.Builder newBuilder()