DUBBO If you do concurrency control, how do
dubbo server and the consumer side concurrency control are done, there are respective corresponding configuration in the configuration:
- Server: executes the largest service provider per service each method can be performed in parallel requests, control the number of concurrent; actives per service per service consumers maximum number of concurrent calls per method, the number of requests occupancy control link; Provider when processing requests, statistical methods call the case dimensions, if the number of concurrent exceeds the maximum setting, the blocking direct throw.
- Consumer end: actives per service per service consumers maximum number of concurrent calls per method; when the Consumer calls, call statistics service and method dimension, if more than the maximum number of concurrent set, then blocks the current thread until the request processing is completed in front .
- If the service side and the consumer side at the same time are equipped with actives, consumer end priority.
/**
* LimitInvokerFilter
*/
@Activate(group = Constants.CONSUMER, value = Constants.ACTIVES_KEY)
public class ActiveLimitFilter implements Filter {
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
URL url = invoker.getUrl();
String methodName = invocation.getMethodName();
int max = invoker.getUrl().getMethodParameter(methodName, Constants.ACTIVES_KEY, 0);
RpcStatus count = RpcStatus.getStatus(invoker.getUrl(), invocation.getMethodName());
if (max > 0) {
long timeout = invoker.getUrl().getMethodParameter(invocation.getMethodName(), Constants.TIMEOUT_KEY, 0);
long start = System.currentTimeMillis();
long remain = timeout;
int active = count.getActive();
if (active >= max) {
synchronized (count) {
while ((active = count.getActive()) >= max) {
try {
count.wait(remain);
} catch (InterruptedException e) {
}
long elapsed = System.currentTimeMillis() - start;
remain = timeout - elapsed;
if (remain <= 0) {
throw new RpcException("Waiting concurrent invoke timeout in client-side for service: "
+ invoker.getInterface().getName() + ", method: "
+ invocation.getMethodName() + ", elapsed: " + elapsed
+ ", timeout: " + timeout + ". concurrent invokes: " + active
+ ". max concurrent invoke limit: " + max);
}
}
}
}
}
try {
long begin = System.currentTimeMillis();
RpcStatus.beginCount(url, methodName);
try {
Result result = invoker.invoke(invocation);
RpcStatus.endCount(url, methodName, System.currentTimeMillis() - begin, true);
return result;
} catch (RuntimeException t) {
RpcStatus.endCount(url, methodName, System.currentTimeMillis() - begin, false);
throw t;
}
} finally {
if (max > 0) {
synchronized (count) {
count.notify();
}
}
}
}
}
/**
* ThreadLimitInvokerFilter
*/
@Activate(group = Constants.PROVIDER, value = Constants.EXECUTES_KEY)
public class ExecuteLimitFilter implements Filter {
public Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {
URL url = invoker.getUrl();
String methodName = invocation.getMethodName();
Semaphore executesLimit = null;
boolean acquireResult = false;
int max = url.getMethodParameter(methodName, Constants.EXECUTES_KEY, 0);
if (max > 0) {
RpcStatus count = RpcStatus.getStatus(url, invocation.getMethodName());
// if (count.getActive() >= max) {
/**
* http://manzhizhen.iteye.com/blog/2386408
* use semaphore for concurrency control (to limit thread number)
*/
executesLimit = count.getSemaphore(max);
if(executesLimit != null && !(acquireResult = executesLimit.tryAcquire())) {
throw new RpcException("Failed to invoke method " + invocation.getMethodName() + " in provider " + url + ", cause: The service using threads greater than <dubbo:service executes=\"" + max + "\" /> limited.");
}
}
long begin = System.currentTimeMillis();
boolean isSuccess = true;
RpcStatus.beginCount(url, methodName);
try {
Result result = invoker.invoke(invocation);
return result;
} catch (Throwable t) {
isSuccess = false;
if (t instanceof RuntimeException) {
throw (RuntimeException) t;
} else {
throw new RpcException("unexpected exception when ExecuteLimitFilter", t);
}
} finally {
RpcStatus.endCount(url, methodName, System.currentTimeMillis() - begin, isSuccess);
if(acquireResult) {
executesLimit.release();
}
}
}
}