Chris Lohfink created CASSANDRA-14670:
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Summary: Table Metrics Virtual Table
Key: CASSANDRA-14670
URL: https://issues.apache.org/jira/browse/CASSANDRA-14670
Project: Cassandra
Issue Type: Improvement
Reporter: Chris Lohfink
Assignee: Chris Lohfink
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:
{code}
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)
{code}
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