我用cassandra 3.11.3构建了一个新集群，并用cassandra 2.0.14从旧集群中填充了数据，将应用程序切换到这个新集群后的几个小时，我遇到了内存错误：
INFO [IndexSummaryManager:1] 2019-05-07 23:44:42,090 IndexSummaryRedistribution.java:77 - Redistributing index summaries
INFO [ReadStage-1] 2019-05-07 23:46:48,394 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ReadStage-1] 2019-05-08 00:01:48,613 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ReadStage-1] 2019-05-08 00:16:48,622 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ReadStage-1] 2019-05-08 00:31:48,778 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [IndexSummaryManager:1] 2019-05-08 00:44:42,761 IndexSummaryRedistribution.java:77 - Redistributing index summaries
INFO [ReadStage-1] 2019-05-08 00:46:48,860 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ReadStage-1] 2019-05-08 01:01:48,863 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ReadStage-1] 2019-05-08 01:16:48,881 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ReadStage-2] 2019-05-08 01:31:49,135 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ReadStage-1] 2019-05-08 01:41:49,962 MonitoringTask.java:93 - Scheduling monitoring task with report interval of 5000 ms, max operations 50
INFO [ScheduledTasks:1] 2019-05-08 01:41:54,972 NoSpamLogger.java:91 - Some operations were slow, details available at debug level (debug.log)
INFO [IndexSummaryManager:1] 2019-05-08 01:44:43,408 IndexSummaryRedistribution.java:77 - Redistributing index summaries
INFO [ReadStage-1] 2019-05-08 01:46:49,502 NoSpamLogger.java:91 - Maximum memory usage reached (536870912), cannot allocate chunk of 1048576
INFO [ScheduledTasks:1] 2019-05-08 01:50:55,000 NoSpamLogger.java:91 - Some operations were slow, details available at debug level (debug.log)
ERROR [ReadStage-3] 2019-05-08 01:57:09,375 JVMStabilityInspector.java:74 - OutOfMemory error letting the JVM handle the error:
java.lang.OutOfMemoryError: null
at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_181]
at java.lang.ClassLoader.defineClass(ClassLoader.java:763) ~[na:1.8.0_181]
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[na:1.8.0_181]
at java.net.URLClassLoader.defineClass(URLClassLoader.java:468) ~[na:1.8.0_181]
at java.net.URLClassLoader.access$100(URLClassLoader.java:74) ~[na:1.8.0_181]
at java.net.URLClassLoader$1.run(URLClassLoader.java:369) ~[na:1.8.0_181]
at java.net.URLClassLoader$1.run(URLClassLoader.java:363) ~[na:1.8.0_181]
at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_181]
at java.net.URLClassLoader.findClass(URLClassLoader.java:362) ~[na:1.8.0_181]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_181]
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349) ~[na:1.8.0_181]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_181]
at org.apache.cassandra.cache.ChunkCache$CachingRebufferer.rebuffer(ChunkCache.java:243) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.cache.ChunkCache$CachingRebufferer.rebuffer(ChunkCache.java:214) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.util.RandomAccessReader.reBufferAt(RandomAccessReader.java:65) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.util.RandomAccessReader.seek(RandomAccessReader.java:207) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.util.FileHandle.createReader(FileHandle.java:150) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.sstable.format.SSTableReader.getFileDataInput(SSTableReader.java:1807) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.columniterator.AbstractSSTableIterator.<init>(AbstractSSTableIterator.java:103) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.columniterator.SSTableIterator.<init>(SSTableIterator.java:49) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.sstable.format.big.BigTableReader.iterator(BigTableReader.java:72) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.sstable.format.big.BigTableReader.iterator(BigTableReader.java:65) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.initializeIterator(UnfilteredRowIteratorWithLowerBound.java:107) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.LazilyInitializedUnfilteredRowIterator.maybeInit(LazilyInitializedUnfilteredRowIterator.java:48) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.getPartitionIndexLowerBound(UnfilteredRowIteratorWithLowerBound.java:191) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.lowerBound(UnfilteredRowIteratorWithLowerBound.java:88) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.lowerBound(UnfilteredRowIteratorWithLowerBound.java:47) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.utils.MergeIterator$Candidate.<init>(MergeIterator.java:362) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.utils.MergeIterator$ManyToOne.<init>(MergeIterator.java:147) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.utils.MergeIterator.get(MergeIterator.java:44) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators$UnfilteredRowMergeIterator.<init>(UnfilteredRowIterators.java:406) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators$UnfilteredRowMergeIterator.create(UnfilteredRowIterators.java:422) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators$UnfilteredRowMergeIterator.access$000(UnfilteredRowIterators.java:385) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators.merge(UnfilteredRowIterators.java:121) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.withSSTablesIterated(SinglePartitionReadCommand.java:848) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.queryMemtableAndDiskInternal(SinglePartitionReadCommand.java:794) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.queryMemtableAndDisk(SinglePartitionReadCommand.java:669) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.queryStorage(SinglePartitionReadCommand.java:503) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.ReadCommand.executeLocally(ReadCommand.java:422) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.service.StorageProxy$LocalReadRunnable.runMayThrow(StorageProxy.java:1887) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.service.StorageProxy$DroppableRunnable.run(StorageProxy.java:2597) ~[apache-cassandra-3.11.3.jar:3.11.3]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_181]
at org.apache.cassandra.concurrent.AbstractLocalAwareExecutorService$FutureTask.run(AbstractLocalAwareExecutorService.java:162) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.concurrent.SEPWorker.run(SEPWorker.java:109) [apache-cassandra-3.11.3.jar:3.11.3]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]
ERROR [ReadStage-3] 2019-05-08 01:57:09,378 JVMStabilityInspector.java:74 - OutOfMemory error letting the JVM handle the error:
java.lang.OutOfMemoryError: null
at java.lang.ClassLoader.defineClass1(Native Method) ~[na:1.8.0_181]
at java.lang.ClassLoader.defineClass(ClassLoader.java:763) ~[na:1.8.0_181]
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) ~[na:1.8.0_181]
at java.net.URLClassLoader.defineClass(URLClassLoader.java:468) ~[na:1.8.0_181]
at java.net.URLClassLoader.access$100(URLClassLoader.java:74) ~[na:1.8.0_181]
at java.net.URLClassLoader$1.run(URLClassLoader.java:369) ~[na:1.8.0_181]
at java.net.URLClassLoader$1.run(URLClassLoader.java:363) ~[na:1.8.0_181]
at java.security.AccessController.doPrivileged(Native Method) ~[na:1.8.0_181]
at java.net.URLClassLoader.findClass(URLClassLoader.java:362) ~[na:1.8.0_181]
at java.lang.ClassLoader.loadClass(ClassLoader.java:424) ~[na:1.8.0_181]
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349) ~[na:1.8.0_181]
at java.lang.ClassLoader.loadClass(ClassLoader.java:357) ~[na:1.8.0_181]
at org.apache.cassandra.cache.ChunkCache$CachingRebufferer.rebuffer(ChunkCache.java:243) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.cache.ChunkCache$CachingRebufferer.rebuffer(ChunkCache.java:214) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.util.RandomAccessReader.reBufferAt(RandomAccessReader.java:65) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.util.RandomAccessReader.seek(RandomAccessReader.java:207) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.util.FileHandle.createReader(FileHandle.java:150) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.sstable.format.SSTableReader.getFileDataInput(SSTableReader.java:1807) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.columniterator.AbstractSSTableIterator.<init>(AbstractSSTableIterator.java:103) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.columniterator.SSTableIterator.<init>(SSTableIterator.java:49) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.sstable.format.big.BigTableReader.iterator(BigTableReader.java:72) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.io.sstable.format.big.BigTableReader.iterator(BigTableReader.java:65) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.initializeIterator(UnfilteredRowIteratorWithLowerBound.java:107) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.LazilyInitializedUnfilteredRowIterator.maybeInit(LazilyInitializedUnfilteredRowIterator.java:48) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.getPartitionIndexLowerBound(UnfilteredRowIteratorWithLowerBound.java:191) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.lowerBound(UnfilteredRowIteratorWithLowerBound.java:88) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIteratorWithLowerBound.lowerBound(UnfilteredRowIteratorWithLowerBound.java:47) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.utils.MergeIterator$Candidate.<init>(MergeIterator.java:362) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.utils.MergeIterator$ManyToOne.<init>(MergeIterator.java:147) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.utils.MergeIterator.get(MergeIterator.java:44) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators$UnfilteredRowMergeIterator.<init>(UnfilteredRowIterators.java:406) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators$UnfilteredRowMergeIterator.create(UnfilteredRowIterators.java:422) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators$UnfilteredRowMergeIterator.access$000(UnfilteredRowIterators.java:385) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.rows.UnfilteredRowIterators.merge(UnfilteredRowIterators.java:121) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.withSSTablesIterated(SinglePartitionReadCommand.java:848) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.queryMemtableAndDiskInternal(SinglePartitionReadCommand.java:794) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.queryMemtableAndDisk(SinglePartitionReadCommand.java:669) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.SinglePartitionReadCommand.queryStorage(SinglePartitionReadCommand.java:503) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.db.ReadCommand.executeLocally(ReadCommand.java:422) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.service.StorageProxy$LocalReadRunnable.runMayThrow(StorageProxy.java:1887) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.service.StorageProxy$DroppableRunnable.run(StorageProxy.java:2597) ~[apache-cassandra-3.11.3.jar:3.11.3]
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[na:1.8.0_181]
at org.apache.cassandra.concurrent.AbstractLocalAwareExecutorService$FutureTask.run(AbstractLocalAwareExecutorService.java:162) ~[apache-cassandra-3.11.3.jar:3.11.3]
at org.apache.cassandra.concurrent.SEPWorker.run(SEPWorker.java:109) ~[apache-cassandra-3.11.3.jar:3.11.3]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]
现在，我非常希望cassandra 3.11.3能够以2.0倍的内存处理与2.0.14相同的负载（以前的群集使用4GB RAM，而这个群集是7.5GB），所以我想我已经设置好了不正确的东西。除非错误是开始使用vnodes。
包含内存设置的命令行为
java -Xloggc:/var/log/cassandra/gc.log -XX:+PrintHeapAtGC -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=50 -XX:GCLogFileSize=100M -ea -XX:+UseThreadPriorities -XX:ThreadPriorityPolicy=42 -XX:+HeapDumpOnOutOfMemoryError -Xss256k -XX:StringTableSize=1000003 -XX:+AlwaysPreTouch -XX:-UseBiasedLocking -XX:+UseTLAB -XX:+ResizeTLAB -XX:+UseNUMA -XX:+PerfDisableSharedMem -Djava.net.preferIPv4Stack=true -XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:+CMSParallelRemarkEnabled -XX:SurvivorRatio=8 -XX:MaxTenuringThreshold=1 -XX:CMSInitiatingOccupancyFraction=75 -XX:+UseCMSInitiatingOccupancyOnly -XX:CMSWaitDuration=10000 -XX:+CMSParallelInitialMarkEnabled -XX:+CMSEdenChunksRecordAlways -XX:+CMSClassUnloadingEnabled -XX:+PrintGCDetails -XX:+PrintGCDateStamps -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:+PrintGCApplicationStoppedTime -XX:+PrintPromotionFailure -XX:+UseGCLogFileRotation -XX:NumberOfGCLogFiles=10 -XX:GCLogFileSize=10M -Xms5120M -Xmx5120M -Xmn800M -XX:CompileCommandFile=/etc/cassandra/hotspot_compiler -javaagent:/usr/share/cassandra/lib/jamm-0.3.0.jar -Dcassandra.jmx.local.port=7199 -Dcom.sun.management.jmxremote.authenticate=false -Dcom.sun.management.jmxremote.password.file=/etc/cassandra/jmxremote.password -Djava.library.path=/usr/share/cassandra/lib/sigar-bin -Dcassandra.libjemalloc=/usr/lib/x86_64-linux-gnu/libjemalloc.so.1 -XX:OnOutOfMemoryError=kill -9 %p -Dlogback.configurationFile=logback.xml -Dcassandra.logdir=/var/log/cassandra -Dcassandra.storagedir=/var/lib/cassandra -Dcassandra-pidfile=/var/run/cassandra/cassandra.pid -cp /etc/cassandra:/usr/share/cassandra/lib/HdrHistogram-2.1.9.jar:/usr/share/cassandra/lib/ST4-4.0.8.jar:/usr/share/cassandra/lib/airline-0.6.jar:/usr/share/cassandra/lib/antlr-runtime-3.5.2.jar:/usr/share/cassandra/lib/asm-5.0.4.jar:/usr/share/cassandra/lib/caffeine-2.2.6.jar:/usr/share/cassandra/lib/cassandra-driver-core-3.0.1-shaded.jar:/usr/share/cassandra/lib/commons-cli-1.1.jar:/usr/share/cassandra/lib/commons-codec-1.9.jar:/usr/share/cassandra/lib/commons-lang3-3.1.jar:/usr/share/cassandra/lib/commons-math3-3.2.jar:/usr/share/cassandra/lib/compress-lzf-0.8.4.jar:/usr/share/cassandra/lib/concurrent-trees-2.4.0.jar:/usr/share/cassandra/lib/concurrentlinkedhashmap-lru-1.4.jar:/usr/share/cassandra/lib/disruptor-3.0.1.jar:/usr/share/cassandra/lib/ecj-4.4.2.jar:/usr/share/cassandra/lib/guava-18.0.jar:/usr/share/cassandra/lib/high-scale-lib-1.0.6.jar:/usr/share/cassandra/lib/hppc-0.5.4.jar:/usr/share/cassandra/lib/jackson-core-asl-1.9.13.jar:/usr/share/cassandra/lib/jackson-mapper-asl-1.9.13.jar:/usr/share/cassandra/lib/jamm-0.3.0.jar:/usr/share/cassandra/lib/javax.inject.jar:/usr/share/cassandra/lib/jbcrypt-0.3m.jar:/usr/share/cassandra/lib/jcl-over-slf4j-1.7.7.jar:/usr/share/cassandra/lib/jctools-core-1.2.1.jar:/usr/share/cassandra/lib/jflex-1.6.0.jar:/usr/share/cassandra/lib/jna-4.2.2.jar:/usr/share/cassandra/lib/joda-time-2.4.jar:/usr/share/cassandra/lib/json-simple-1.1.jar:/usr/share/cassandra/lib/jstackjunit-0.0.1.jar:/usr/share/cassandra/lib/libthrift-0.9.2.jar:/usr/share/cassandra/lib/log4j-over-slf4j-1.7.7.jar:/usr/share/cassandra/lib/logback-classic-1.1.3.jar:/usr/share/cassandra/lib/logback-core-1.1.3.jar:/usr/share/cassandra/lib/lz4-1.3.0.jar:/usr/share/cassandra/lib/metrics-core-3.1.5.jar:/usr/share/cassandra/lib/metrics-jvm-3.1.5.jar:/usr/share/cassandra/lib/metrics-logback-3.1.5.jar:/usr/share/cassandra/lib/netty-all-4.0.44.Final.jar:/usr/share/cassandra/lib/ohc-core-0.4.4.jar:/usr/share/cassandra/lib/ohc-core-j8-0.4.4.jar:/usr/share/cassandra/lib/reporter-config-base-3.0.3.jar:/usr/share/cassandra/lib/reporter-config3-3.0.3.jar:/usr/share/cassandra/lib/sigar-1.6.4.jar:/usr/share/cassandra/lib/slf4j-api-1.7.7.jar:/usr/share/cassandra/lib/snakeyaml-1.11.jar:/usr/share/cassandra/lib/snappy-java-1.1.1.7.jar:/usr/share/cassandra/lib/snowball-stemmer-1.3.0.581.1.jar:/usr/share/cassandra/lib/stream-2.5.2.jar:/usr/share/cassandra/lib/thrift-server-0.3.7.jar:/usr/share/cassandra/apache-cassandra-3.11.3.jar:/usr/share/cassandra/apache-cassandra-thrift-3.11.3.jar:/usr/share/cassandra/apache-cassandra.jar:/usr/share/cassandra/stress.jar: -XX:HeapDumpPath=/var/lib/cassandra/java_1557299542.hprof -XX:ErrorFile=/var/lib/cassandra/hs_err_1557299542.log org.apache.cassandra.service.CassandraDaemon
nodetool信息（重新启动并切换回应用程序之后）报告：
ID : d1f45a7e-0344-4806-894e-20c2ad4a2915
Gossip active : true
Thrift active : true
Native Transport active: true
Load : 189.55 GiB
Generation No : 1557299590
Uptime (seconds) : 4433
Heap Memory (MB) : 1284.83 / 5040.00
Off Heap Memory (MB) : 56.34
Data Center : dc1
Rack : rack1
Exceptions : 0
Key Cache : entries 52231, size 4.39 MiB, capacity 100 MiB, 212159 hits, 440743 requests, 0.481 recent hit rate, 14400 save period in seconds
Row Cache : entries 0, size 0 bytes, capacity 0 bytes, 0 hits, 0 requests, NaN recent hit rate, 0 save period in seconds
Counter Cache : entries 0, size 0 bytes, capacity 50 MiB, 0 hits, 0 requests, NaN recent hit rate, 7200 save period in seconds
Chunk Cache : entries 6672, size 417.06 MiB, capacity 480 MiB, 1053622 misses, 1313584 requests, 0.198 recent hit rate, 180.246 microseconds miss latency
Percent Repaired : 99.93543489030424%
Token : (invoke with -T/--tokens to see all 256 tokens)
最大的表似乎没有太大的分区：
nodetool cfhistograms main1 articles
main1/articles histograms
Percentile SSTables Write Latency Read Latency Partition Size Cell Count
(micros) (micros) (bytes)
50% 1.00 29.52 1358.10 3311 12
75% 1.00 61.21 1955.67 4768 12
95% 1.00 88.15 4866.32 9887 14
98% 2.00 88.15 7007.51 14237 14
99% 2.00 88.15 8409.01 17084 24
Min 1.00 17.09 61.22 259 8
Max 3.00 88.15 36157.19 5839588 35
还有其他我应该提供的信息吗？ ..哦，集群很小，只有两台机器。
答案 0 :(得分：2)
5gb堆（-Xmx5120M）低于建议的最小堆大小8gb。尽管您可能需要对其进行调整以使其正常工作，但该数据库并未设计为在有限的堆中运行时使用其默认值。可能最快，最可能的方法是将concurrent_reads和concurrent_writes设置为8或4。然后将concurrent_compactors和concurrent_validations（如果是最新版本）设置为1。 / p>
如果您设置了-XX:+HeapDumpOnOutOfMemoryError和-XX:HeapDumpPath=/somewhere/writable，那么它将在OOM上转储堆，您可以打开它并查看原因。如果得到它，则可以发布堆直方图（在转储上使用jmap），人们也许可以给出更多的指示-但实际上可能需要使用yourkit或MAT之类的工具来摸索，以了解确切的原因。
如果那是一个死角，则可以使用async profiler
sudo -u [cassandra user] profiler.sh -e alloc -d 60 [cassandra pid]
或sjk
sudo -u [cassandra user] java -jar sjk.jar hh -p [cassandra pid] --dead-young
了解随着时间的推移将生成哪些对象。