Re: Data aggregation - averages, sums, etc.
Continuous computation is the sort of thing Storm (https://github.com/nathanmarz/storm) can help with. And good news everybody, storing the output from Storm is the sort of thing Cassandra can help with http://www.youtube.com/watch?v=cF8a_FZwULI Cheers - Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 20/05/2012, at 6:17 AM, Janne Jalkanen wrote: 2. I know I have counter columns. I can do sums. But can I do averages ? One counter column for the sum, one counter column for the count. Divide for average :-) /Janne
Data aggregation - averages, sums, etc.
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 ?
Re: Data aggregation - averages, sums, etc.
2. I know I have counter columns. I can do sums. But can I do averages ? One counter column for the sum, one counter column for the count. Divide for average :-) /Janne
