accumulo-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Adam Fuchs <adam.p.fu...@ugov.gov>
Subject Re: Using maxVersions=7 but rows disappear
Date Wed, 11 Apr 2012 18:20:22 GMT
David,

In case of continuing confusion, I think it's best if you ignore Bill's
suggestion for now and heed Josh's advice. Bill's suggestion might be an
optimization to look at later on, but your initial approach seems sound.

Adam



On Tue, Apr 10, 2012 at 10:52 PM, David Medinets
<david.medinets@gmail.com>wrote:

> I thought there were issues associated with doing mutations inside
> iterators?
>
> On Tue, Apr 10, 2012 at 10:35 PM, William Slacum <wslacum@gmail.com>
> wrote:
> > 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?
> >
>

Mime
View raw message