我正在尝试两件关于我们基于cassandra的应用程序的事情，这是不可能为了测试目的而停止所有服务的：
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，我们需要知道当前的工作负载，例如cassandra的读写操作。
获取一些信息，比如一个表包含的总行数（我们的表目前有将近80亿条记录）&每周插入多少条记录（有一些数据源我们无法控制，因此很难直接从insert脚本获取这些信息）。
我尝试了一些解决这两个问题的方法：
在评论中更新。 select count(*) from 根本不起作用，而且太慢了。我试着利用 nodetool tablestats ，以分布式系统为例：

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

有些参数我无法理解：
答。本地写入计数是什么意思？如果一个表分布在不同的节点上，并且有多个副本，那么如何计算该表的行数？
b。前5行（读计数、写计数）是否描述了该键空间的信息（system\u distributed）？
c。这里的所有延迟是指平均延迟吗
如果你们能给我任何建议，我将不胜感激。
嘉实