读取时CPU使用率很高

Question

我正在使用cassandra 1.2.5，在集群中有4个节点。 每个节点均为m1.large，系统内存为8GB。 对我们来说，阅读会更多。 我的栏族中有50,000行。 每当我尝试从该列系列读取数据时，每次node3或node4的CPU使用率都很高。 我已经在下面给出了日志。

我们是否可以针对此问题将压缩策略设置为LeveledCompactionStrategy并将sstable_size_in_mb设置为10。 这会有所帮助吗？

还有其他解决方案吗？

日志：

 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,660 StatusLogger.java (line 95) Cache Type                     Size                 Capacity               KeysToSave                                                         Provider
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,660 StatusLogger.java (line 96) KeyCache                   18523284                 52428800                      all      
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,661 StatusLogger.java (line 102) RowCache                          0               1073741824                      all              org.apache.cassandra.cache.SerializingCacheProvider
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,661 StatusLogger.java (line 109) ColumnFamily                Memtable ops,data
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,661 StatusLogger.java (line 112) system.local                              0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,661 StatusLogger.java (line 112) system.peers                          60,8040
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,662 StatusLogger.java (line 112) system.batchlog                           0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,671 StatusLogger.java (line 112) system.NodeIdInfo                         0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,671 StatusLogger.java (line 112) system.LocationInfo                       0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,671 StatusLogger.java (line 112) system.Schema                             0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,671 StatusLogger.java (line 112) system.Migrations                         0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,672 StatusLogger.java (line 112) system.schema_keyspaces                 8,251
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,672 StatusLogger.java (line 112) system.schema_columns               332,21903
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,672 StatusLogger.java (line 112) system.schema_columnfamilies           352,21775
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,672 StatusLogger.java (line 112) system.IndexInfo                          0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,672 StatusLogger.java (line 112) system.range_xfers                        0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,673 StatusLogger.java (line 112) system.peer_events                        0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,673 StatusLogger.java (line 112) system.hints                              0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,673 StatusLogger.java (line 112) system.HintsColumnFamily                  0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,673 StatusLogger.java (line 112) GEN_GEN.feedserver_dependentFeeds                 0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,673 StatusLogger.java (line 112) GEN_GEN.feedserver_componentName       18648,1048576
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,674 StatusLogger.java (line 112) GEN_GEN.feedserver_FeedScheduler      128952,2097152
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,739 StatusLogger.java (line 112) GEN_GEN.feedserver_feedType                 0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,739 StatusLogger.java (line 112) GEN_GEN.feedserver_itemDef                 0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,739 StatusLogger.java (line 112) GEN_GEN.feedserver_Feed         66629,2097152
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,740 StatusLogger.java (line 112) system_auth.users                         0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,740 StatusLogger.java (line 112) OpsCenter.events                          0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,740 StatusLogger.java (line 112) OpsCenter.rollups60                       0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,740 StatusLogger.java (line 112) OpsCenter.settings                        0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,740 StatusLogger.java (line 112) OpsCenter.pdps                            0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,741 StatusLogger.java (line 112) OpsCenter.rollups86400                    0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,741 StatusLogger.java (line 112) OpsCenter.events_timeline                 0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,741 StatusLogger.java (line 112) OpsCenter.rollups300                      0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,741 StatusLogger.java (line 112) OpsCenter.rollups7200                     0,0
 INFO [ScheduledTasks:1] 2013-07-25 12:59:04,741 StatusLogger.java (line 112) system_traces.sessions                    0,0

Answer 1

如果在读取期间看到内存压力，则可能一次读取太多行。 跟踪请求可以更清楚地了解正在发生的事情： http : //www.datastax.com/dev/blog/tracing-in-cassandra-1-2