这篇文章主要介绍了mongo慢查询问题如何排查处理的相关知识，内容详细易懂，操作简单快捷，具有一定借鉴价值，相信大家阅读完这篇mongo慢查询问题如何排查处理文章都会有所收获，下面我们一起来看看吧。
一、简单介绍
mongo语句查询条件中出现null或空串，可能会导致索引失效，查询优化器无法选择正确的查询计划，出现慢查询引起服务异常
mongo查询的执行计划使用了LRU缓存，在很多种情况下会失效，导致重新选择执行计划并缓存，供后续同类查询直接使用；
服务开始时一直运行正常，当执行计划失效后，恰好出现null值的查询导致选择了错误的执行计划并缓存，后续正常的查询也会出现异常。
二、事件脉络
1、起因
用户中心收到业务方反馈，第三方登录注册出现频繁dubbo调用超时。
org.apache.dubbo.rpc.RpcException: Failed to invoke the method loginWithThird in the service weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService. Tried 1 times of the providers [10.65.5.0:11090] (1/4) from the registry node1.zk.all.platform.wtc.hwhosts.com:2181 on the consumer 10.65.1.81 using the dubbo version 2.7.3-SNAPSHOT. Last error is: loginWithThird_2 failed and fallback failed. at org.apache.dubbo.rpc.cluster.support.FailoverClusterInvoker.doInvoke(FailoverClusterInvoker.java:113) at org.apache.dubbo.rpc.cluster.support.AbstractClusterInvoker.invoke(AbstractClusterInvoker.java:248) at org.apache.dubbo.rpc.cluster.support.wrapper.MockClusterInvoker.invoke(MockClusterInvoker.java:78) at org.apache.dubbo.rpc.proxy.InvokerInvocationHandler.invoke(InvokerInvocationHandler.java:55) at org.apache.dubbo.common.bytecode.proxy9.loginWithThird(proxy9.java) at weli.peanut.user.service.LoginService.loginAndRegister(LoginService.java:684) at weli.peanut.user.service.LoginService.loginByThirdPartyV2(LoginService.java:629) at weli.peanut.web.controller.api.UserLoginController.lambda$loginByThirdPartyV2$0(UserLoginController.java:113) at weli.peanut.common.controller.BaseController.resultForActionWithCat(BaseController.java:71) at weli.peanut.web.controller.api.UserLoginController.loginByThirdPartyV2(UserLoginController.java:113) at sun.reflect.GeneratedMethodAccessor2017.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205) at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:133) at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827) at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738) at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85) at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963) at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897) at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970) at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:872) at javax.servlet.http.HttpServlet.service(HttpServlet.java:646) at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846) at javax.servlet.http.HttpServlet.service(HttpServlet.java:727) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197) at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107) at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241) at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208) at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220) at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122) at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:501) at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170) at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98) at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116) at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408) at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1040) at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:607) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1721) at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1679) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748)Caused by: com.netflix.hystrix.exception.HystrixRuntimeException: loginWithThird_2 failed and fallback failed. at com.netflix.hystrix.AbstractCommand$22.call(AbstractCommand.java:818) at com.netflix.hystrix.AbstractCommand$22.call(AbstractCommand.java:793) at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:140) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87) at com.netflix.hystrix.AbstractCommand$DeprecatedOnFallbackHookApplication$1.onError(AbstractCommand.java:1454) at com.netflix.hystrix.AbstractCommand$FallbackHookApplication$1.onError(AbstractCommand.java:1379) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87) at rx.observers.Subscribers$5.onError(Subscribers.java:230) at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:44) at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:28) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OperatorOnErrorResumeNextViaFunction$4.onError(OperatorOnErrorResumeNextViaFunction.java:142) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87) at rx.internal.operators.OperatorSubscribeOn$1$1.onError(OperatorSubscribeOn.java:59) at rx.observers.Subscribers$5.onError(Subscribers.java:230) at rx.internal.operators.OnSubscribeDoOnEach$DoOnEachSubscriber.onError(OnSubscribeDoOnEach.java:87) at rx.observers.Subscribers$5.onError(Subscribers.java:230) at com.netflix.hystrix.AbstractCommand$DeprecatedOnRunHookApplication$1.onError(AbstractCommand.java:1413) at com.netflix.hystrix.AbstractCommand$ExecutionHookApplication$1.onError(AbstractCommand.java:1344) at rx.observers.Subscribers$5.onError(Subscribers.java:230) at rx.observers.Subscribers$5.onError(Subscribers.java:230) at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:44) at rx.internal.operators.OnSubscribeThrow.call(OnSubscribeThrow.java:28) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:51) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:35) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:41) at rx.internal.operators.OnSubscribeDoOnEach.call(OnSubscribeDoOnEach.java:30) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:48) at rx.internal.operators.OnSubscribeLift.call(OnSubscribeLift.java:30) at rx.Observable.unsafeSubscribe(Observable.java:10151) at rx.internal.operators.OperatorSubscribeOn$1.call(OperatorSubscribeOn.java:94) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:56) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction$1.call(HystrixContexSchedulerAction.java:47) at com.netflix.hystrix.strategy.concurrency.HystrixContexSchedulerAction.call(HystrixContexSchedulerAction.java:69) at rx.internal.schedulers.ScheduledAction.run(ScheduledAction.java:55) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) ... 3 moreCaused by: java.lang.RuntimeException: org.apache.dubbo.rpc.RpcException: Invoke remote method timeout. method: loginWithThird, provider: dubbo://10.65.5.0:11090/weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService?anyhost=true&application=peanut-admin&bean.name=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService&check=false&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService&lazy=false&loadbalance=leastactive&methods=logout,sendSms,loginWithVisitor,loginWithThird,loginWithPhone,loginWithThirdBindPhone&pid=1®ister=true®ister.ip=10.65.1.81&release=2.7.3-SNAPSHOT&remote.application=wormhole-api&retries=0&revision=1.1.11-SNAPSHOT&side=consumer&sticky=false&timeout=5000×tamp=1647332146309, cause: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2022-03-15 20:33:31.937, end time: 2022-03-15 20:33:36.968, client elapsed: 0 ms, server elapsed: 5031 ms, timeout: 5000 ms, request: Request [id=690506, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=loginWithThird, parameterTypes=[class weli.wormhole.rpc.user.center.model.LoginWithThirdRequest, class weli.wormhole.rpc.user.center.model.LoginCommonParam], arguments=[LoginWithThirdRequest(accessToken=54_y3n-YsttdKOklr_X-mbjRgKAKROLDKfx3PV23zAQHmBvmT3zVliFp9mWodHSUEcKgNnJGC4AP_bAOX-2ZSSsfCHfNM5wfjbJDyiQh-sCjFQ, openId=ofrsY6xraPjv9augA9L2kUIB0-Fk, unionId=null, code=null, type=WX, nickName=null, headImgurl=null, sex=null, skipPhoneBind=1), LoginCommonParam(channel=vivo, ip=null, verName=null, platform=null, deviceId=null, imei=null, app=peanut, subApp=peanut, dfId=DUE_59hD2L9BBgukNR3Jv2DjnW00iRtU8z0eRFVFXzU5aEQyTDlCQmd1a05SM0p2MkRqblcwMGlSdFU4ejBlc2h2, idfa=null, mac=null, oaid=null, androidId=null)], attachments={path=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, interface=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, version=0.0.0, timeout=5000}]], channel: /10.65.1.81:35450 -> /10.65.5.0:11090 at suishen.esb.hystrix.dubbo.DubboHystrixCommand.run(DubboHystrixCommand.java:93) at suishen.esb.hystrix.dubbo.DubboHystrixCommand.run(DubboHystrixCommand.java:12) at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:301) at com.netflix.hystrix.HystrixCommand$2.call(HystrixCommand.java:297) at rx.internal.operators.OnSubscribeDefer.call(OnSubscribeDefer.java:46) ... 26 moreCaused by: org.apache.dubbo.rpc.RpcException: Invoke remote method timeout. method: loginWithThird, provider: dubbo://10.65.5.0:11090/weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService?anyhost=true&application=peanut-admin&bean.name=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService&check=false&deprecated=false&dubbo=2.0.2&dynamic=true&generic=false&interface=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService&lazy=false&loadbalance=leastactive&methods=logout,sendSms,loginWithVisitor,loginWithThird,loginWithPhone,loginWithThirdBindPhone&pid=1®ister=true®ister.ip=10.65.1.81&release=2.7.3-SNAPSHOT&remote.application=wormhole-api&retries=0&revision=1.1.11-SNAPSHOT&side=consumer&sticky=false&timeout=5000×tamp=1647332146309, cause: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2022-03-15 20:33:31.937, end time: 2022-03-15 20:33:36.968, client elapsed: 0 ms, server elapsed: 5031 ms, timeout: 5000 ms, request: Request [id=690506, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=loginWithThird, parameterTypes=[class weli.wormhole.rpc.user.center.model.LoginWithThirdRequest, class weli.wormhole.rpc.user.center.model.LoginCommonParam], arguments=[LoginWithThirdRequest(accessToken=54_y3n-YsttdKOklr_X-mbjRgKAKROLDKfx3PV23zAQHmBvmT3zVliFp9mWodHSUEcKgNnJGC4AP_bAOX-2ZSSsfCHfNM5wfjbJDyiQh-sCjFQ, openId=ofrsY6xraPjv9augA9L2kUIB0-Fk, unionId=null, code=null, type=WX, nickName=null, headImgurl=null, sex=null, skipPhoneBind=1), LoginCommonParam(channel=vivo, ip=null, verName=null, platform=null, deviceId=null, imei=null, app=peanut, subApp=peanut, dfId=DUE_59hD2L9BBgukNR3Jv2DjnW00iRtU8z0eRFVFXzU5aEQyTDlCQmd1a05SM0p2MkRqblcwMGlSdFU4ejBlc2h2, idfa=null, mac=null, oaid=null, androidId=null)], attachments={path=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, interface=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, version=0.0.0, timeout=5000}]], channel: /10.65.1.81:35450 -> /10.65.5.0:11090 at org.apache.dubbo.rpc.protocol.AsyncToSyncInvoker.invoke(AsyncToSyncInvoker.java:63) at org.apache.dubbo.rpc.listener.ListenerInvokerWrapper.invoke(ListenerInvokerWrapper.java:78) at com.alibaba.dubbo.rpc.Invoker$CompatibleInvoker.invoke(Invoker.java:55) at suishen.esb.hystrix.dubbo.DubboHystrixCommand.run(DubboHystrixCommand.java:84) ... 30 moreCaused by: java.util.concurrent.ExecutionException: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2022-03-15 20:33:31.937, end time: 2022-03-15 20:33:36.968, client elapsed: 0 ms, server elapsed: 5031 ms, timeout: 5000 ms, request: Request [id=690506, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=loginWithThird, parameterTypes=[class weli.wormhole.rpc.user.center.model.LoginWithThirdRequest, class weli.wormhole.rpc.user.center.model.LoginCommonParam], arguments=[LoginWithThirdRequest(accessToken=54_y3n-YsttdKOklr_X-mbjRgKAKROLDKfx3PV23zAQHmBvmT3zVliFp9mWodHSUEcKgNnJGC4AP_bAOX-2ZSSsfCHfNM5wfjbJDyiQh-sCjFQ, openId=ofrsY6xraPjv9augA9L2kUIB0-Fk, unionId=null, code=null, type=WX, nickName=null, headImgurl=null, sex=null, skipPhoneBind=1), LoginCommonParam(channel=vivo, ip=null, verName=null, platform=null, deviceId=null, imei=null, app=peanut, subApp=peanut, dfId=DUE_59hD2L9BBgukNR3Jv2DjnW00iRtU8z0eRFVFXzU5aEQyTDlCQmd1a05SM0p2MkRqblcwMGlSdFU4ejBlc2h2, idfa=null, mac=null, oaid=null, androidId=null)], attachments={path=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, interface=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, version=0.0.0, timeout=5000}]], channel: /10.65.1.81:35450 -> /10.65.5.0:11090 at java.util.concurrent.CompletableFuture.reportGet(CompletableFuture.java:357) at java.util.concurrent.CompletableFuture.get(CompletableFuture.java:1915) at org.apache.dubbo.rpc.protocol.AsyncToSyncInvoker.invoke(AsyncToSyncInvoker.java:56) ... 33 moreCaused by: org.apache.dubbo.remoting.TimeoutException: Waiting server-side response timeout by scan timer. start time: 2022-03-15 20:33:31.937, end time: 2022-03-15 20:33:36.968, client elapsed: 0 ms, server elapsed: 5031 ms, timeout: 5000 ms, request: Request [id=690506, version=2.0.2, twoway=true, event=false, broken=false, data=RpcInvocation [methodName=loginWithThird, parameterTypes=[class weli.wormhole.rpc.user.center.model.LoginWithThirdRequest, class weli.wormhole.rpc.user.center.model.LoginCommonParam], arguments=[LoginWithThirdRequest(accessToken=54_y3n-YsttdKOklr_X-mbjRgKAKROLDKfx3PV23zAQHmBvmT3zVliFp9mWodHSUEcKgNnJGC4AP_bAOX-2ZSSsfCHfNM5wfjbJDyiQh-sCjFQ, openId=ofrsY6xraPjv9augA9L2kUIB0-Fk, unionId=null, code=null, type=WX, nickName=null, headImgurl=null, sex=null, skipPhoneBind=1), LoginCommonParam(channel=vivo, ip=null, verName=null, platform=null, deviceId=null, imei=null, app=peanut, subApp=peanut, dfId=DUE_59hD2L9BBgukNR3Jv2DjnW00iRtU8z0eRFVFXzU5aEQyTDlCQmd1a05SM0p2MkRqblcwMGlSdFU4ejBlc2h2, idfa=null, mac=null, oaid=null, androidId=null)], attachments={path=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, interface=weli.wormhole.rpc.user.center.api.ILoginNeedPhoneService, version=0.0.0, timeout=5000}]], channel: /10.65.1.81:35450 -> /10.65.5.0:11090 at org.apache.dubbo.remoting.exchange.support.DefaultFuture.doReceived(DefaultFuture.java:189) at org.apache.dubbo.remoting.exchange.support.DefaultFuture.received(DefaultFuture.java:153) at org.apache.dubbo.remoting.exchange.support.DefaultFuture$TimeoutCheckTask.run(DefaultFuture.java:252) at org.apache.dubbo.common.timer.HashedWheelTimer$HashedWheelTimeout.expire(HashedWheelTimer.java:648) at org.apache.dubbo.common.timer.HashedWheelTimer$HashedWheelBucket.expireTimeouts(HashedWheelTimer.java:727) at org.apache.dubbo.common.timer.HashedWheelTimer$Worker.run(HashedWheelTimer.java:449) ... 1 more2、排查处理
a、查询用户中心cat监控，确认用户中心是否收到请求且正常响应。
当前状态：
正常状态：
对比结果：
用户中心已收到正常请求，排除客户端调用问题；
用户中心当前响应时间异常高出平常的响应时间，判断为用户中心内部业务处理出现问题。
b、查看kibana日志，发现无异常日志；
c、使用Arthas诊断工具，监控业务调用链各部分耗时情况；
定位原因为mongo查询慢导致整体业务处理超时。
d、分析mongo查询语句，查看索引情况
public User getUserByDfId(String dfId, String app) { Criteria criteria = Criteria.where("userBindInfo.dfId").is(dfId).and("app").is(app).and("status").is(1); return this.mongoTemplate.findOne(Query.query(criteria), User.class);}db.getCollection('wormhole_user').getIndexes();[ { "v" : 1, "key" : { "app" : 1 }, "name" : "app", "ns" : "wormhole.wormhole_user", "background" : true }, { "v" : 1, "key" : { "userBindInfo.dfId" : 1 }, "name" : "userBindInfo.dfId", "ns" : "wormhole.wormhole_user", "background" : true }, ... (其余不关注索引已删除)]“userBindInfo.dfId”字段存在索引，查询语句也无明显异常。
e、查看华为云后台mongo慢日志
{ "op": "query", "ns": "wormhole.wormhole_user", "command": { "find": "wormhole_user", "filter": { "userBindInfo.dfId": "DUQmN3QLpLRwC8PNe1joT_9SDRrzazT4cUc5RFVRbU4zUUxwTFJ3QzhQTmUxam9UXzlTRFJyemF6VDRjVWM1c2h2", "app": "maybe", "status": 1 }, "ntoreturn": -1 }, "keysExamined": 1870039, "docsExamined": 1870039, "cursorExhausted": true, "numYield": 14836, "nreturned": 0, "locks": { "Global": { "acquireCount": { "r": 14837 } }, "Database": { "acquireCount": { "r": 14837 } }, "Collection": { "acquireCount": { "r": 14837 } } }, "responseLength": 36, "millis": 14545, "planSummary": "IXSCAN { app: 1 }", "execStats": { "stage": "CACHED_PLAN", "nReturned": 0, "executionTimeMillisEstimate": 14552, "works": 1, "advanced": 0, "needTime": 0, "needYield": 0, "saveState": 14836, "restoreState": 14836, "isEOF": 1, "invalidates": 0, "inputStage": { "stage": "LIMIT", "nReturned": 0, "executionTimeMillisEstimate": 14145, "works": 1870040, "advanced": 0, "needTime": 1870039, "needYield": 0, "saveState": 14836, "restoreState": 14836, "isEOF": 1, "invalidates": 0, "limitAmount": 1, "inputStage": { "stage": "FETCH", "filter": { "$and": [ { "status": { "$eq": 1 } }, { "userBindInfo.dfId": { "$eq": "DUQmN3QLpLRwC8PNe1joT_9SDRrzazT4cUc5RFVRbU4zUUxwTFJ3QzhQTmUxam9UXzlTRFJyemF6VDRjVWM1c2h2" } } ] }, "nReturned": 0, "executionTimeMillisEstimate": 14117, "works": 1870040, "advanced": 0, "needTime": 1870039, "needYield": 0, "saveState": 14836, "restoreState": 14836, "isEOF": 1, "invalidates": 0, "docsExamined": 1870039, "alreadyHasObj": 0, "inputStage": { "stage": "IXSCAN", "nReturned": 1870039, "executionTimeMillisEstimate": 931, "works": 1870040, "advanced": 1870039, "needTime": 0, "needYield": 0, "saveState": 14836, "restoreState": 14836, "isEOF": 1, "invalidates": 0, "keyPattern": { "app": 1 }, "indexName": "app", "isMultiKey": false, "multiKeyPaths": { "app": [] }, "isUnique": false, "isSparse": false, "isPartial": false, "indexVersion": 1, "direction": "forward", "indexBounds": { "app": [ "["maybe", "maybe"]" ] }, "keysExamined": 1870039, "seeks": 1, "dupsTested": 0, "dupsDropped": 0, "seenInvalidated": 0 } } } }, "ts": { "$date": 1647359086553 }, "client": "10.65.5.0", "allUsers": [ { "user": "mongosiud", "db": "wormhole" } ], "user": "mongosiud@wormhole"}通过慢日志发现，mongo并未使用“userBindInfo.dfId”作为索引查询条件，而是使用了“app”作为索引查询条件。
初步认为索引匹配度不够，mongo没正确使用索引。
f、新增联合索引，提高索引匹配度，查询时间恢复正常，接口恢复正常。
db.getCollection("wormhole_user").createIndex({ "userBindInfo.dfId": 1, "app": 1, "status": 1 }, { name: "idx_user_app_userBindInfo.dfId", background: true});3、问题分析
a、explain()语句分析
db.getCollection('wormhole_user').find({"userBindInfo.dfId": "DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2", "app": "maybe", "status": 1}).explain();{ "queryPlanner" : { "plannerVersion" : 1, "namespace" : "wormhole.wormhole_user", "indexFilterSet" : false, "parsedQuery" : { "$and" : [ { "app" : { "$eq" : "maybe" } }, { "status" : { "$eq" : 1.0 } }, { "userBindInfo.dfId" : { "$eq" : "DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2" } } ] }, "winningPlan" : { "stage" : "FETCH", "filter" : { "$and" : [ { "app" : { "$eq" : "maybe" } }, { "status" : { "$eq" : 1.0 } } ] }, "inputStage" : { "stage" : "IXSCAN", "keyPattern" : { "userBindInfo.dfId" : 1 }, "indexName" : "userBindInfo.dfId", "isMultiKey" : false, "multiKeyPaths" : { "userBindInfo.dfId" : [] }, "isUnique" : false, "isSparse" : false, "isPartial" : false, "indexVersion" : 1, "direction" : "forward", "indexBounds" : { "userBindInfo.dfId" : [ "[\"DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2\", \"DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2\"]" ] } } }, "rejectedPlans" : [ { "stage" : "FETCH", "filter" : { "$and" : [ { "status" : { "$eq" : 1.0 } }, { "userBindInfo.dfId" : { "$eq" : "DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2" } } ] }, "inputStage" : { "stage" : "IXSCAN", "keyPattern" : { "app" : 1 }, "indexName" : "app", "isMultiKey" : false, "multiKeyPaths" : { "app" : [] }, "isUnique" : false, "isSparse" : false, "isPartial" : false, "indexVersion" : 1, "direction" : "forward", "indexBounds" : { "app" : [ "[\"maybe\", \"maybe\"]" ] } } }, { "stage" : "FETCH", "filter" : { "$and" : [ { "app" : { "$eq" : "maybe" } }, { "userBindInfo.dfId" : { "$eq" : "DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2" } }, { "status" : { "$eq" : 1.0 } } ] }, "inputStage" : { "stage" : "AND_SORTED", "inputStages" : [ { "stage" : "IXSCAN", "keyPattern" : { "app" : 1 }, "indexName" : "app", "isMultiKey" : false, "multiKeyPaths" : { "app" : [] }, "isUnique" : false, "isSparse" : false, "isPartial" : false, "indexVersion" : 1, "direction" : "forward", "indexBounds" : { "app" : [ "[\"maybe\", \"maybe\"]" ] } }, { "stage" : "IXSCAN", "keyPattern" : { "userBindInfo.dfId" : 1 }, "indexName" : "userBindInfo.dfId", "isMultiKey" : false, "multiKeyPaths" : { "userBindInfo.dfId" : [] }, "isUnique" : false, "isSparse" : false, "isPartial" : false, "indexVersion" : 1, "direction" : "forward", "indexBounds" : { "userBindInfo.dfId" : [ "[\"DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2\", \"DUqTmV8lQcInjzWtuyJuAntkbRi5_YZ3yHd9RFVxVG1WOGxRY0luanpXdHV5SnVBbnRrYlJpNV9ZWjN5SGQ5c2h2\"]" ] } } ] } } ] }, "serverInfo" : { "host" : "host-192-168-10-163", "port" : 27017, "version" : "4.0.3", "gitVersion" : "0ead8608f9d151a199b05117bcc79ccb8d5f44a0" }, "ok" : 1.0, "operationTime" : Timestamp(1647486920, 2), "$clusterTime" : { "clusterTime" : Timestamp(1647486920, 2), "signature" : { "hash" : { "$binary" : "ylTAtLK6mVpNwDt7PTGwNST/9z4=", "$type" : "00" }, "keyId" : NumberLong(7031512438860152835) } }}发现mongo执行计划选择正确，这正好解释了服务在之前很长的一段时间内都是正常的原因；
mongo慢日志中的执行计划却选择错误，表明有什么原因导致了mongo执行计划的选择发生了变更。
b、文档查询
MongoDB 查询优化器会缓存最有效的查询计划，关联的计划缓存条目会用于具有相同查询形状的后续查询；
计划缓存会出现刷新：
MongoDB重启；
索引或者集合的删除添加更新等操作；
最近最少使用 (LRU) 缓存替换机制清除最近最少访问的缓存条目。
结论：之前使用了计划缓存服务正常，到了某一时刻，计划缓存失效，MongoDB重新选择计划，此时选择了错误的计划并缓存，导致后续查询全部出现问题
c、查询首次出现的慢日志
{ "op":"query", "ns":"wormhole.wormhole_user", "command":{ "find":"wormhole_user", "filter":{ "userBindInfo.dfId":null, "app":"cybercat", "status":1 }, "ntoreturn":-1 }, "keysExamined":872550, "docsExamined":872550, "fromMultiPlanner":true, "replanned":true, "cursorExhausted":true, "numYield":13785, "nreturned":0, "locks":{ "Global":{ "acquireCount":{ "r":13786 } }, "Database":{ "acquireCount":{ "r":13786 } }, "Collection":{ "acquireCount":{ "r":13786 } } }, "responseLength":36, "millis":27864, "planSummary":"IXSCAN { app: 1 }", "execStats":{ "stage":"LIMIT", "nReturned":0, "executionTimeMillisEstimate":26216, "works":872551, "advanced":0, "needTime":872550, "needYield":0, "saveState":13785, "restoreState":13785, "isEOF":1, "invalidates":0, "limitAmount":1, "inputStage":{ "stage":"FETCH", "filter":{ "$and":[ { "status":{ "$eq":1 } }, { "userBindInfo.dfId":{ "$eq":null } } ] }, "nReturned":0, "executionTimeMillisEstimate":26164, "works":872551, "advanced":0, "needTime":872550, "needYield":0, "saveState":13785, "restoreState":13785, "isEOF":1, "invalidates":0, "docsExamined":872550, "alreadyHasObj":0, "inputStage":{ "stage":"IXSCAN", "nReturned":872550, "executionTimeMillisEstimate":249, "works":872551, "advanced":872550, "needTime":0, "needYield":0, "saveState":13785, "restoreState":13785, "isEOF":1, "invalidates":0, "keyPattern":{ "app":1 }, "indexName":"app", "isMultiKey":false, "multiKeyPaths":{ "app":[ ] }, "isUnique":false, "isSparse":false, "isPartial":false, "indexVersion":1, "direction":"forward", "indexBounds":{ "app":["["cybercat", "cybercat"]" ] }, "keysExamined":872550, "seeks":1, "dupsTested":0, "dupsDropped":0, "seenInvalidated":0 } } }, "ts":{ "$date":1647309521700 }, "client":"10.65.1.25", "allUsers":[ { "user":"mongosiud", "db":"wormhole" } ], "user":"mongosiud@wormhole"}发现查询条件中出现了null值，本地再次分析：
db.getCollection('wormhole_user').find({"userBindInfo.dfId": null, "app": "maybe", "status": 1}).explain();{ "queryPlanner" : { "plannerVersion" : 1, "namespace" : "wormhole.wormhole_user", "indexFilterSet" : false, "parsedQuery" : { "$and" : [ { "app" : { "$eq" : "maybe" } }, { "status" : { "$eq" : 1.0 } }, { "userBindInfo.dfId" : { "$eq" : null } } ] }, "winningPlan" : { "stage" : "FETCH", "filter" : { "$and" : [ { "status" : { "$eq" : 1.0 } }, { "userBindInfo.dfId" : { "$eq" : null } } ] }, "inputStage" : { "stage" : "IXSCAN", "keyPattern" : { "app" : 1 }, "indexName" : "app", "isMultiKey" : false, "multiKeyPaths" : { "app" : [] }, "isUnique" : false, "isSparse" : false, "isPartial" : false, "indexVersion" : 1, "direction" : "forward", "indexBounds" : { "app" : [ "[\"maybe\", \"maybe\"]" ] } } }, "rejectedPlans" : [ { "stage" : "FETCH", "filter" : { "$and" : [ { "userBindInfo.dfId" : { "$eq" : null } }, { "app" : { "$eq" : "maybe" } }, { "status" : { "$eq" : 1.0 } } ] }, "inputStage" : { "stage" : "IXSCAN", "keyPattern" : { "userBindInfo.dfId" : 1 }, "indexName" : "userBindInfo.dfId", "isMultiKey" : false, "multiKeyPaths" : { "userBindInfo.dfId" : [] }, "isUnique" : false, "isSparse" : false, "isPartial" : false, "indexVersion" : 1, "direction" : "forward", "indexBounds" : { "userBindInfo.dfId" : [ "[undefined, undefined]", "[null, null]" ] } } } ] }, "serverInfo" : { "host" : "host-192-168-10-163", "port" : 27017, "version" : "4.0.3", "gitVersion" : "0ead8608f9d151a199b05117bcc79ccb8d5f44a0" }, "ok" : 1.0, "operationTime" : Timestamp(1647489666, 1), "$clusterTime" : { "clusterTime" : Timestamp(1647489666, 1), "signature" : { "hash" : { "$binary" : "1KJI3aoz2QbOwTKlbkNl9SmWLzw=", "$type" : "00" }, "keyId" : NumberLong(7031512438860152835) } }}结果与线上表现一致
4、回顾
紧急处理时，直接创建了一个新的索引，导致了计划缓存失效，重新选择计划并缓存，所以服务恢复了正常。
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