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From "Jonathan Ellis (JIRA)" <>
Subject [jira] [Commented] (CASSANDRA-2830) Allow summing of counter columns in CQL
Date Tue, 24 Apr 2012 14:31:35 GMT


Jonathan Ellis commented on CASSANDRA-2830:

My problem with this is that I don't have a clear line in my head between supporting {{WHERE
KEY IN (...)}}, which is clearly bounded in terms of space and time required, and any arbitrary
WHERE clause (indexed or even seq scan).

Kind of inclined to say "we should leave aggregation to Hive."
> Allow summing of counter columns in CQL
> ---------------------------------------
>                 Key: CASSANDRA-2830
>                 URL:
>             Project: Cassandra
>          Issue Type: New Feature
>          Components: API
>            Reporter: Tomas Salfischberger
>            Priority: Minor
>              Labels: CQL
> CQL could be extended with a method to calculate the sum of a set of counter columns.
This avoids transferring a long list of counter columns to be summed by the client, while
the server could calculate the total and instead only transfer that result. My proposal for
the syntax (based on the COUNT() suggestion in the comments of CASSANDRA-1704):
> {code}SELECT SUM(<columnFrom>..<columnTo>) FROM <CF> WHERE ...{code}
> The simplest approach would be to only allow summing of counters under the same key,
thus a query with a WHERE part that specifies multiple keys would return 1 result per key.
This avoids summing values from different nodes.

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