I don't know. I'd need to see how it didn't end up being a crazy mess where it was very difficult to tell what kind of filter you needed to perform, like we had before Jun split ReadCommand up into different classes. (https://issues.apache.org/jira/browse/CASSANDRA-95)
(This was an internal change, the thrift api has always been what it is.) -Jonathan On Tue, Jun 30, 2009 at 1:55 PM, Evan Weaver<[email protected]> wrote: > Since the API is so thorny right now, it would be extremely difficult > to automate filter calls. What if we had something like follows > (pardon my bogus syntax): > > resultUnion_n get_one(column_family:string, key:string, > [super_column:string], [column:string], [options:Something_t]) > list<resultUnion_n> get_all(column_family:string, key:string, > [super_column:string], [column:string], [options:Something_t]) > > where resultUnion_n is: (scalar | Column_t | SuperColumn_t) > > Ideally Column_t and SuperColumn_t could be merged, but that's not a big deal. > > The options struct/dict could have the composable filters of various kinds. > > Is this even remotely possible? > > Evan > > On Sun, Jun 28, 2009 at 5:49 AM, Bill de hOra<[email protected]> wrote: >> Evan Weaver wrote: >>> >>> I wanted to start a small discussion to see if there is any interest >>> in supporting alternative wire protocols or perhaps junking Thrift to >>> some degree. >>> >>> Some options: >>> * Use JSON over HTTP >>> * Use BSON over...something (http://www.mongodb.org/display/DOCS/BSON) >>> * Use ASN.1 over...something >>> * Use Protocol Buffers over...something >>> * Use Thrift, but package Cassandra-specific clients for each language >>> >>> I have not thought too coherently about this but generic Thrift seems >>> to be a pain point for everybody. >> >> Hi Evan, >> >> I've been playing around again with Cassandra recently and I agree Thrift is >> a pain point, and that was the case when I looked at the project originally. >> But I think it's not so much Thrift as how the data is presented to clients. >> >> Much more important to me is that to use Cassandra means reading and >> understanding the service api calls in cassandra.thrift. Personally I >> wouldn't have designed a fine grained API over the generic data structures >> implied by a colum store, where simple filters and selects become a litany >> of get_by_X calls. For example, 4 methods return list<column_t>, 2 return >> list<string>, 2 return list<superColumn_t>, there are 5 get_slice and 4 >> get_column variants. And typical of RPC, none of this stuff composes. In >> something like Django there are chained filter() calls (Hibernate has >> similar Criteria calls) which makes for a stable programming API, where what >> you need to figure out the criteria to pass. With Cassandra you have to do >> that and find the right method; the API surface is much bigger. Simple >> keystores and dynamo style models get away with fine grained RPC as there's >> nothing much to do except the key lookup and multiget usecases. They're not >> a design sweetspot for column stores APIs imvho. >> >> I think the question for Cassandra is not so much about serialization >> techniques and speed as whether RPC is the best way to expose the data. >> >> Bill >> > > > > -- > Evan Weaver >
