[RATIS-1300] NPE from SegmentedRaftLogCache#getOpenSegmentSizeInBytes

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Fixed
• Target Version/s: 2.0.0
• Assignee: runzhiwang
• Reporter: Marton Elek
• Created: 28/Jan/21 12:31
• Updated: 05/Feb/21 10:16
• Resolved: 05/Feb/21 05:05

Description

Got this exception during Ozone tests:

2021-01-28 12:29:41 WARN  HttpChannel:600 - /prom
java.lang.NullPointerException: Cannot invoke "org.apache.ratis.server.raftlog.segmented.LogSegment.getTotalFileSize()" because "this.openSegment" is null
	at org.apache.ratis.server.raftlog.segmented.SegmentedRaftLogCache.getOpenSegmentSizeInBytes(SegmentedRaftLogCache.java:402)
	at org.apache.ratis.server.metrics.SegmentedRaftLogMetrics.lambda$null$6(SegmentedRaftLogMetrics.java:104)
	at io.prometheus.client.dropwizard.DropwizardExports.fromGauge(DropwizardExports.java:62)
	at io.prometheus.client.dropwizard.DropwizardExports.collect(DropwizardExports.java:132)
	at io.prometheus.client.CollectorRegistry$MetricFamilySamplesEnumeration.findNextElement(CollectorRegistry.java:190)
	at io.prometheus.client.CollectorRegistry$MetricFamilySamplesEnumeration.nextElement(CollectorRegistry.java:223)
	at io.prometheus.client.CollectorRegistry$MetricFamilySamplesEnumeration.nextElement(CollectorRegistry.java:144)
	at io.prometheus.client.exporter.common.TextFormat.write004(TextFormat.java:22)
	at org.apache.hadoop.hdds.server.http.PrometheusServlet.doGet(PrometheusServlet.java:66)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:687)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:791)
	at org.eclipse.jetty.servlet.ServletHandler$ChainEnd.doFilter(ServletHandler.java:1626)
	at org.apache.hadoop.http.lib.StaticUserWebFilter$StaticUserFilter.doFilter(StaticUserWebFilter.java:110)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)
	at org.apache.hadoop.hdds.server.http.HttpServer2$QuotingInputFilter.doFilter(HttpServer2.java:1667)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)
	at org.apache.hadoop.hdds.server.http.NoCacheFilter.doFilter(NoCacheFilter.java:48)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:193)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1601)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:548)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:602)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:235)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1612)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:233)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1434)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:188)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:501)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1582)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:186)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1349)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
	at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:146)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:127)
	at org.eclipse.jetty.server.Server.handle(Server.java:516)
	at org.eclipse.jetty.server.HttpChannel.lambda$handle$1(HttpChannel.java:383)
	at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:556)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:375)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:273)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:311)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:105)
	at org.eclipse.jetty.io.ChannelEndPoint$1.run(ChannelEndPoint.java:104)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:336)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:313)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:171)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:129)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:375)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:773)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:905)
	at java.base/java.lang.Thread.run(Thread.java:832)

There shouldn't be any NPE, IMHO.

Issue Links

• links to: GitHub Pull Request #417