I don't think you'd necessarily need a an aggregator for that, although it doesn't seem like that's what you're doing here in the first place. Wouldn't it be easier to set a summation iterator that also keeps a count of of observations to do some server side math and then combine it all on the client? That way you can have a time series and to get weekly averages you just change your scan range. On Apr 10, 2012, at 10:16 PM, David Medinets wrote:
> I'm still thinking about how to use accumulo to calculate weekly > moving averages. I thought that using the maxVersions settings might > work to maintain the last 7 values. Then a program could simply sum > the values of a given row. So this is what I did: > > bin/accumulo shell -u root -p password >> createtable rolling > rolling> config -t rolling -s table.iterator.scan.vers.opt.maxVersions=7 > rolling> insert row cf cq 1 > rolling> insert row cf cq 2 > rolling> insert row cf cq 3 > rolling> insert row cf cq 4 > rolling> insert row cf cq 5 > rolling> insert row cf cq 6 > rolling> insert row cf cq 7 > rolling> insert row cf cq 8 > rolling> scan > row cf:cq [] 8 > row cf:cq [] 7 > row cf:cq [] 6 > row cf:cq [] 5 > row cf:cq [] 4 > row cf:cq [] 3 > row cf:cq [] 2 > > This is exactly what I wanted to see. So I wrote a simple scanner > program to read the table. Then I did another scan: > > rolling> scan > row cf:cq [] 8 > > Where did the rest of the records go?
