运行WSO2 APIM v2.0作为2个节点集群，WSO2 DAS作为单独的节点。
每次在WSO2 APIM中发生限制时，我都会在网关错误日志中看到以下错误消息
2016-11-04 06:23:59,927 [-] [PassThroughMessageProcessor-27] ERROR APIMgtThrottleUsageHandler Cannot publish throttling event. null
java.lang.NullPointerException
at org.wso2.carbon.utils.multitenancy.MultitenantUtils.getTenantDomain(MultitenantUtils.java:90)
at org.wso2.carbon.apimgt.usage.publisher.APIMgtThrottleUsageHandler.mediate(APIMgtThrottleUsageHandler.java:71)
at org.apache.synapse.mediators.ext.ClassMediator.mediate(ClassMediator.java:84)
at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:95)
at org.apache.synapse.mediators.AbstractListMediator.mediate(AbstractListMediator.java:57)
at org.apache.synapse.mediators.base.SequenceMediator.mediate(SequenceMediator.java:158)
at org.wso2.carbon.apimgt.gateway.handlers.throttling.ThrottleHandler.handleThrottleOut(ThrottleHandler.java:612)
at org.wso2.carbon.apimgt.gateway.handlers.throttling.ThrottleHandler.doThrottle(ThrottleHandler.java:504)
at org.wso2.carbon.apimgt.gateway.handlers.throttling.ThrottleHandler.handleRequest(ThrottleHandler.java:445)
at org.apache.synapse.rest.API.process(API.java:325)
at org.apache.synapse.rest.RESTRequestHandler.dispatchToAPI(RESTRequestHandler.java:90)
at org.apache.synapse.rest.RESTRequestHandler.process(RESTRequestHandler.java:69)
at org.apache.synapse.core.axis2.Axis2SynapseEnvironment.injectMessage(Axis2SynapseEnvironment.java:300)
at org.apache.synapse.core.axis2.SynapseMessageReceiver.receive(SynapseMessageReceiver.java:75)
at org.apache.axis2.engine.AxisEngine.receive(AxisEngine.java:180)
at org.apache.synapse.transport.passthru.ServerWorker.processNonEntityEnclosingRESTHandler(ServerWorker.java:319)
at org.apache.synapse.transport.passthru.ServerWorker.run(ServerWorker.java:152)
at org.apache.axis2.transport.base.threads.NativeWorkerPool$1.run(NativeWorkerPool.java:172)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
我也无法从WSO2 APIM统计数据中看到API Throttled Out Requests报告。
请建议。