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Posted to commits@cassandra.apache.org by "Jon Haddad (JIRA)" <ji...@apache.org> on 2019/07/02 16:21:00 UTC
[jira] [Comment Edited] (CASSANDRA-14670) Table Metrics Virtual
Table
[ https://issues.apache.org/jira/browse/CASSANDRA-14670?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16877109#comment-16877109 ]
Jon Haddad edited comment on CASSANDRA-14670 at 7/2/19 4:20 PM:
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When I did the review on it, I had the same thought, but after changing the code around to work differently I realized the UX is significantly better with count as the first element of the partition key.
It doesn't make sense when you look at it from a code-first perspective but the user interface in CQLSH is far superior than the alternative.
Having tried it both ways, I can say the current implementation is the better option. Requiring the operator to specify the {{ORDER BY}} clause is significantly worse UX.
was (Author: rustyrazorblade):
When I did the review on it, I had the same thought, but after changing the code around to work differently I realized the UX is significantly better with count as the first element of the partition key.
It doesn't make sense when you look at it from a code-first perspective but the user interface in CQLSH is far superior than the alternative.
Having tried it both ways, I can say this is the better option. Requiring the operator to specify the {{ORDER BY}} clause is significantly worse UX.
> Table Metrics Virtual Table
> ---------------------------
>
> Key: CASSANDRA-14670
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14670
> Project: Cassandra
> Issue Type: Improvement
> Components: Legacy/CQL, Legacy/Observability
> Reporter: Chris Lohfink
> Assignee: Chris Lohfink
> Priority: Low
> Labels: pull-request-available, virtual-tables
> Fix For: 4.0.x
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> 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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