我在监控我的Cassandra节点时出现问题。我跑了
nodetool cfstats keyspaceName.tableName
不幸的是,Read Count始终为0,Read Latency为NaN。我正在进行读写操作,但只会更新写入指标。
以下是我得到的结果:
Starting NodeTool
Keyspace: realtimetrader
Read Count: 0
Read Latency: NaN ms.
Write Count: 402
Write Latency: 0.09648756218905473 ms.
Pending Flushes: 0
Table: currencies
SSTable count: 1
Space used (live): 5254
Space used (total): 5254
Space used by snapshots (total): 0
Off heap memory used (total): 40
SSTable Compression Ratio: 0.0
Number of keys (estimate): 14
Memtable cell count: 1608
Memtable data size: 567
Memtable off heap memory used: 0
Memtable switch count: 0
Local read count: 0
Local read latency: NaN ms
Local write count: 402
Local write latency: 0.106 ms
Pending flushes: 0
Bloom filter false positives: 0
Bloom filter false ratio: 0,00000
Bloom filter space used: 24
Bloom filter off heap memory used: 16
Index summary off heap memory used: 16
Compression metadata off heap memory used: 8
Compacted partition minimum bytes: 125
Compacted partition maximum bytes: 149
Compacted partition mean bytes: 149
Average live cells per slice (last five minutes): 0.0
Maximum live cells per slice (last five minutes): 0
Average tombstones per slice (last five minutes): 0.0
Maximum tombstones per slice (last five minutes): 0
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我感谢任何帮助。
答案 0 :(得分:3)
由于每个节点负责一组不同的数据,因此您读取的所有数据都可能属于其他节点。许多驱动程序都具有令牌识别负载平衡策略,该策略将读取发送到应该拥有它的节点。使用CL.ONE默认一致性,这也意味着它将快速发送读取到其他节点(除了达到读取修复机会的情况)。
根据您使用的版本以及您提出的查询,您可能也看不到此增量:https://issues.apache.org/jira/browse/CASSANDRA-7338