You are seeing this http://wiki.apache.org/cassandra/FAQ#range_rp
The hash for (uuid-1 , p1) may be 100 and the hash for (uuid-1, p2) may be 1 . You cannot do what you want to. Even if you passed a start of (uuid1,<empty>) and no finish, you would not only get rows where the key starts with uuid1. This may be of use to you http://www.datastax.com/dev/blog/schema-in-cassandra-1-1 Or you can store all the priorities that are valid for an ID in another row. Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com On 14/03/2012, at 1:05 PM, John Laban wrote: > Forwarding to the Cassandra mailing list as well, in case this is more of an > issue on how I'm using Cassandra. > > Am I correct to assume that I can use range queries on composite row keys, > even when using a RandomPartitioner, if I make sure that the first part of > the composite key is fixed? > > Any help would be appreciated, > John > > > > On Tue, Mar 13, 2012 at 12:15 PM, John Laban <j...@pagerduty.com> wrote: > Hi, > > I have a column family that uses a composite key: > > (ID, priority) -> ... > > Where the ID is a UUID and the priority is an integer. > > I'm trying to perform a range query now: I want all the rows where the ID > matches some fixed UUID, but within a range of priorities. This is supported > even if I'm using a RandomPartitioner, right? (Because the first key in the > composite key is the partition key, and the second part of the composite key > is automatically ordered?) > > So I perform a range slices query: > > val rangeQuery = HFactory.createRangeSlicesQuery(keyspace, new > CompositeSerializer, StringSerializer.get, BytesArraySerializer.get) > rangeQuery.setColumnFamily(RouteColumnFamilyName). > setKeys( new Composite(id, priorityStart), new Composite(id, > priorityEnd) ). > setRange( null, null, false, Int.MaxValue ) > > > But I get this error: > > me.prettyprint.hector.api.exceptions.HInvalidRequestException: > InvalidRequestException(why:start key's md5 sorts after end key's md5. this > is not allowed; you probably should not specify end key at all, under > RandomPartitioner) > > Shouldn't they have the same md5, since they have the same partition key? > > Am I using the wrong query here, or does Hector not support composte range > queries, or am I making some mistake in how I think Cassandra's composite > keys work? > > Thanks, > John > >
