Most of the high level clients do this for you. For example, pycassa and phpcassa both do this by returning an iterator from get_range() and breaking it up behind the scenes.
Hector also has something similar, but I think it's in the examples section. What client are you using? (By the way, beta1 is old and buggy! You should switch to beta3.) - Tyler On Fri, Nov 19, 2010 at 8:33 AM, <alta...@ceid.upatras.gr> wrote: > Hello, > > I would like one of the cluster's nodes to use get_range_slices() to > retrieve the values of a specific column for the entire keyspace. I > obviously don't want to do it for the whole keyspace at once, so I'd like > to do it in groups of n, which should be configurable. > > I get the first n values using a KeyRange with the current node's local > token as start_token and end_token, which equals the whole keyspace. > > After that, it makes sense to have a loop, and to use each time a new > KeyRange with the largest key returned by the previous iteration as the > start_key. However, I don't know what to use as end_key, and Cassandra > complains that if one of (start_key, end_key) is not null, the other can't > be either. What can I do? > > Can I use tokens? I read that a KeyRange with tokens is end-inclusive, and > can wrap, so I can just give the local node's token as the end_token all > the time, so when the traversing reaches that node again, it will know the > whole keyspace was traversed. Or are tokens different semantically? > > I am using Cassandra 0.7.0 beta1, and the OrderPreservingPartitioner. > > Alexander Altanis > > > > > >
