[CASSANDRA-6644] CQL: Select every nth row within the same partition key

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Duplicate
• Assignee: Unassigned
• Reporter: Jorge Bay
• Created: 31/Jan/14 10:38
• Updated: 16/Apr/19 09:31
• Resolved: 31/Jan/14 14:44

Description

In a time-series schema (like metrics), it is common to create roollups/buckets with datapoints at different rate.
It would be nice to have a keyword in CQL to be able to retrieve one every nth row (within a single storage engine wide row).

For example, in the following schema:

CREATE TABLE metrics (
... metric_id varchar,
... ts timestamp,
... value float,
... PRIMARY KEY (metric_id, ts)
... );

The following query, will retrieve 1 in every 3 rows:

(SKIP keyword or something like that, but don't focus on the syntax)
SELECT ts, value WHERE metric_id = ? SKIP 2;

This would be very useful for continuous (and somehow linear) metrics.

Issue Links

• duplicates: CASSANDRA-4914 Aggregation functions in CQL