我正在尝试关于我们基于 Cassandra 的应用程序的两件事，这不可能停止所有服务以进行测试：
- 使用 python 驱动程序测试 op/s 和 99.9% 延迟等性能。为了得到更准确的结果，我们想知道当前的工作负载，例如 Cassandra 的读写 op/s。
- 获取一些信息，例如一个表包含的总行数（我们的表现在有近 80 亿条记录）以及每周插入多少条记录（有一些我们无法控制的数据源，因此很难从插入脚本中获取这些信息直接地）。
对于这两个问题，我尝试了一些方法：
在评论中更新。
select count(*) from xxx根本不起作用，而且速度太慢。我尝试使用 获取一些信息nodetool tablestats，以 system_distributed 为例：
Keyspace : system_distributed
Read Count: 0
Read Latency: NaN ms
Write Count: 0
Write Latency: NaN ms
Pending Flushes: 0
Table: parent_repair_history
SSTable count: 0
Space used (live): 0
Space used (total): 0
Space used by snapshots (total): 0
Off heap memory used (total): 0
SSTable Compression Ratio: -1.0
Number of partitions (estimate): 0
Memtable cell count: 0
Memtable data size: 0
Memtable off heap memory used: 0
Memtable switch count: 0
Local read count: 0
Local read latency: NaN ms
Local write count: 0
Local write latency: NaN ms
Pending flushes: 0
Percent repaired: 100.0
Bloom filter false positives: 0
Bloom filter false ratio: 0.00000
Bloom filter space used: 0
Bloom filter off heap memory used: 0
Index summary off heap memory used: 0
Compression metadata off heap memory used: 0
Compacted partition minimum bytes: 0
Compacted partition maximum bytes: 0
Compacted partition mean bytes: 0
Average live cells per slice (last five minutes): NaN
Maximum live cells per slice (last five minutes): 0
Average tombstones per slice (last five minutes): NaN
Maximum tombstones per slice (last five minutes): 0
Dropped Mutations: 0
Table: repair_history
SSTable count: 0
Space used (live): 0
Space used (total): 0
Space used by snapshots (total): 0
Off heap memory used (total): 0
SSTable Compression Ratio: -1.0
Number of partitions (estimate): 0
Memtable cell count: 0
Memtable data size: 0
Memtable off heap memory used: 0
Memtable switch count: 0
Local read count: 0
Local read latency: NaN ms
Local write count: 0
Local write latency: NaN ms
Pending flushes: 0
Percent repaired: 100.0
Bloom filter false positives: 0
Bloom filter false ratio: 0.00000
Bloom filter space used: 0
Bloom filter off heap memory used: 0
Index summary off heap memory used: 0
Compression metadata off heap memory used: 0
Compacted partition minimum bytes: 0
Compacted partition maximum bytes: 0
Compacted partition mean bytes: 0
Average live cells per slice (last five minutes): NaN
Maximum live cells per slice (last five minutes): 0
Average tombstones per slice (last five minutes): NaN
Maximum tombstones per slice (last five minutes): 0
Dropped Mutations: 0
Table: view_build_status
SSTable count: 0
Space used (live): 0
Space used (total): 0
Space used by snapshots (total): 0
Off heap memory used (total): 0
SSTable Compression Ratio: -1.0
Number of partitions (estimate): 0
Memtable cell count: 0
Memtable data size: 0
Memtable off heap memory used: 0
Memtable switch count: 0
Local read count: 0
Local read latency: NaN ms
Local write count: 0
Local write latency: NaN ms
Pending flushes: 0
Percent repaired: 100.0
Bloom filter false positives: 0
Bloom filter false ratio: 0.00000
Bloom filter space used: 0
Bloom filter off heap memory used: 0
Index summary off heap memory used: 0
Compression metadata off heap memory used: 0
Compacted partition minimum bytes: 0
Compacted partition maximum bytes: 0
Compacted partition mean bytes: 0
Average live cells per slice (last five minutes): NaN
Maximum live cells per slice (last five minutes): 0
Average tombstones per slice (last five minutes): NaN
Maximum tombstones per slice (last five minutes): 0
Dropped Mutations: 0
这些有一些我无法理解的参数：
一个。本地写入计数是什么意思？如果我有一个分布在不同节点上的表并且有多个副本，如何计算该表的多少行？
湾。前 5 行（读取计数、写入计数）是否描述了该键空间（system_distributed）的信息？
C。这里所有的延迟是指平均延迟吗？</p>
不胜感激，如果你们能给我任何建议。
嘉实