[jira] [Commented] (CASSANDRA-8878) Counter Tables should be more clearly identified

["David Reitter (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-8878?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14705847#comment-14705847 ] 

David Reitter commented on CASSANDRA-8878:
------------------------------------------

I would like to second either proposed change.

I'm a brand-new user, and I ran into a very much related problem that is not adequately addressed by the documentation: 

CREATE TABLE lexFreqs (node_id text, PRIMARY KEY (node_id));
ALTER TABLE lexFreqs ADD ftest counter;
--> Error  (Not a counter column family).

Solution:

CREATE TABLE lexFreqs (node_id text, dummy counter, PRIMARY KEY (node_id));
ALTER TABLE lexFreqs ADD ftest counter;
--> works.


> Counter Tables should be more clearly identified
> ------------------------------------------------
>
>                 Key: CASSANDRA-8878
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-8878
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Michaël Figuière
>            Assignee: Aleksey Yeschenko
>            Priority: Minor
>             Fix For: 3.x
>
>
> Counter tables are internally considered as a particular kind of table, different from the regular ones. This counter specific nature is implicitly defined by the fact that columns within a table have the {{counter}} data type. This nature turns out to be persistent over the time, that is if the user do the following:
> {code}
> CREATE TABLE counttable (key uuid primary key, count counter);
> ALTER TABLE counttable DROP count;
> ALTER TABLE counttable ADD count2 int;
> {code} 
> The following error will be thrown:
> {code}
> Cannot add a non counter column (count2) in a counter column family
> {code}
> Even if the table doesn't have any counter column anymore. This implicit, persistent nature can be challenging to understand for users (and impossible to infer in the case above). For this reason a more explicit declaration of counter tables would be appropriate, as:
> {code}
> CREATE COUNTER TABLE counttable (key uuid primary key, count counter);
> {code}
> Besides that, adding a boolean {{counter_table}} column in the {{system.schema_columnfamilies}} table would allow external tools to easily differentiate a counter table from a regular one.



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