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From: Oleg Dulin <oleg.dulin@gmail.com>
Subject: Data aggregation - averages, sums, etc.
Date: Sat, 19 May 2012 12:04:35 +0000 (UTC)
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Dear distinguished colleagues:

I am trying to come up with a data model that lets me do aggregations, such
as sums and averages.

Here are my requirements:

1. Data may be updated concurrently
2. I want to avoid changing schema; we have a multitennant cloud solution
that is driven by configuration. Schema is the same for all customs.

Here is what I have at my disposal:

1. We have a proprietary distributed in memory column store that acts as a
buffer between the server and Cassandra. Frequent reads are not a problem.
2. I know I have counter columns. I can do sums. But can I do averages ?

One of the ideas is to record data as it comes in organized by time and
periodically aggregate it.

Thoughts ?