cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Henrik Schröder <>
Subject Re: Range scan performance in 0.6.0 beta2
Date Mon, 29 Mar 2010 13:13:55 GMT
On Mon, Mar 29, 2010 at 14:15, Jonathan Ellis <> wrote:

> On Mon, Mar 29, 2010 at 4:06 AM, Henrik Schröder <>
> wrote:
> > On Fri, Mar 26, 2010 at 14:47, Jonathan Ellis <> wrote:
> >> It's a unique index then?  And you're trying to read things ordered by
> >> the index, not just "give me keys with that have a column with this
> >> value?"
> >
> > Yes, because if we have more than one column per row, there's no way of
> > (easily) limiting the result.
> That's exactly what the count parameter of SliceRange is for... ?

I thought that only limited the number of columns per key?

We're using the get_range_slices method, which takes both a SlicePredicate
(which contains a range, which contains a count) and a KeyRange (which also
contains a count). Say that we have a bunch of keys that each contain 10
columns, and we do a get_range_slices over those, how do we get the first 25
columns? If we put it in the SliceRange count, we'll get all matching rows,
and the 25 first columns of each, right? And if we put it in the KeyRange
count, we'll get the 25 first rows that match, and all their columns, right?

But if we have only one column per row, then we can limit the results the
way we want to. Or have we misunderstood the api somehow?


View raw message