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From "Sylvain Lebresne (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-8878) Counter Tables should be more clearly identified
Date Tue, 03 Mar 2015 10:13:05 GMT


Sylvain Lebresne commented on CASSANDRA-8878:

For the record, I'm in favor of adding the {{CREATE COUNTER TABLE}} syntax as that's imo the
more explicit (and counter tables are different enough that it's worth being explicit), though
obviously for the sake of backward compatibility we'll have to leave that optional. Still,
we can encourage using the new syntax once we have it, and perhaps more importantly, cqlsh
{{DESCRIBE}} can start including it for counters table, making the example of the description
less surprising.

> Counter Tables should be more clearly identified
> ------------------------------------------------
>                 Key: CASSANDRA-8878
>                 URL:
>             Project: Cassandra
>          Issue Type: Improvement
>            Reporter: Michaël Figuière
>            Assignee: Aleksey Yeschenko
>            Priority: Minor
>             Fix For: 3.0
> 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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