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      Different than CASSANDRA-14572 whose goal is to expose all metrics. This is to expose a few hand tailored tables that are particularly useful in debugging slow Cassandra instances (in my experience). These are useful in finding out which table it is that is having issues if you see a node performing poorly in general. This can kinda be figured out with cfstats sorting and some clever bash-foo but its been a bit of a operational UX pain for me personally for awhile.

      examples:

      cqlsh> select * from system_views.max_partition_size limit 5;
      
       max_partition_size | keyspace_name | table_name
      --------------------+---------------+----------------
                   126934 |        system | size_estimates
                     9887 | system_schema |        columns
                     9887 | system_schema |         tables
                     6866 |        system |          local
                      258 |     keyspace1 |      standard1
      
      (5 rows)
      
      cqlsh> select * from system_views.local_reads limit 5 ;
      
       count | keyspace_name | table_name      | 99th      | max       | median  | per_second
      -------+---------------+-----------------+-----------+-----------+---------+------------
          23 |        system |           local | 186563160 | 186563160 | 1629722 |    3.56101
          22 | system_schema |          tables |   4055269 |   4055269 |  454826 |    3.72452
          14 | system_schema |         columns |   1131752 |   1131752 |  545791 |    2.37015
          14 | system_schema | dropped_columns |    126934 |    126934 |   88148 |    2.37015
          14 | system_schema |         indexes |    219342 |    219342 |  152321 |    2.37015
      
      (5 rows)
      
      cqlsh> select * from system_views.coordinator_reads limit 5;
      
       count | keyspace_name | table_name | 99th | max | median | per_second
      -------+---------------+------------+------+-----+--------+------------
           2 |        system |      local |    0 |   0 |      0 |   0.005324
           1 |   system_auth |      roles |    0 |   0 |      0 |   0.002662
           0 |         basic |       wide |    0 |   0 |      0 |          0
           0 |         basic |      wide3 |    0 |   0 |      0 |          0
           0 |     keyspace1 |   counter1 |    0 |   0 |      0 |          0
      
      (5 rows)
      
      

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              • Assignee:
                cnlwsu Chris Lohfink
                Reporter:
                cnlwsu Chris Lohfink
                Authors:
                Chris Lohfink
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