Hi Bryan, Thanks for the answers! A few more questions inline:
On Tue, Nov 27, 2012 at 2:16 PM, Bryan Fink <br...@basho.com> wrote: > Hi, Alex. I'm sorry you weren't able to find your answers in our docs. > Some of them assume that you've read all of the other docs as well. > I'll see what I can do to clear things up inline. > > On Mon, Nov 26, 2012 at 7:23 PM, Alex Rønne Petersen > <xtzgzo...@gmail.com> wrote: >> * Is the proper way to replace the object associated with a bucket/key >> pair to simply do a riakc_pb_socket:put/2 with the same bucket/key >> pair (with a new object)? > > This one is answered in the "Modifying Data" section of the README: > > https://github.com/basho/riak-erlang-client/blob/master/README.md#modifying-data I don't know how I managed to miss that. Thanks! > > In short, the proper way to replace an object is to first fetch the > existing object, then update the value of what you fetched, then use > riakc_pb_socket:put to write the new value. The reason for doing this > is to comply with Riak's consistency system (the vector clocks) - it > needs to know what value you were starting from in order to overwrite > it correctly. OK, makes sense. Just out of curiosity, though, is updating values via put without an update a supported scenario in some way or is it generally considered a Bad Idea (tm)? > >> * What exactly is the purpose of riakc_obj:update_value/2 (with >> regards to the above question)? > > The riakc_obj structure stores two different things: the > value+metadata you read, and the value+metadata you want to write. The > update_value and update_metadata functions set the value+metadata you > want to write. The same can be said about get_value/get_metadata and > get_update_value/get_update_metadata - they each access one part of > the riakc_obj structure. Although, as was discussed recently on this > list, get_update_value will return the result of get_value if no > update value has been set. > >> * How does one associate a secondary index with an object? Is this >> done via riakc_obj:update_metadata/2? > > Yes, you need to set the "index" metadata entry to associate a > secondary index with an object. For example, to set values the > "myidx_bin" and "youridx_int" indexes: > > Obj = riakc_obj:new(Bucket, Key, Value). > Idx = [{"myidx_bin", "hello"},{"youridx_int","9876"}]. > MD = dict:store(<<"index">>, Idx, dict:new()). > ObjIndexed = riakc_obj:update_metadata(Obj, MD). > riakc_pb_socket:put(Socket, ObjIndexed). > > If overwriting a value, you would use the result of > riakc_obj:get_metadata/1 instead of dict:new/0 for building your new > metadata. Does Riak figure out based on the name of the index what type it is? That is, *_int = integer, *_bin = string? Is there any physical limit to how many secondary indexes can be created for an object? Or perhaps a recommended limit? > >> * Is there any particular reason the Erlang client doesn't yet support >> all bucket properties? > > Yes, it does not support the bucket properties that the Protocol > Buffers interface to Riak does not support. It's a known problem. You > can follow work on it here: > > https://github.com/basho/riak_pb/issues/5 > > In the meantime, the riak-erlang-http-client can be used to set other > bucket properties: > > https://github.com/basho/riak-erlang-http-client > >> * What exactly do the various get and put options do? Specifically, >> if_modified, notfound_ok, basic_quorum, head, and deletedvclock for >> the former > > These answers can be found in the docs for the Protocol Buffers get message: > > http://docs.basho.com/riak/latest/references/apis/protocol-buffers/PBC-Fetch-Object/ > > and return_body, return_head, if_not_modified, and >> if_none_match for the former. > > And these answers are in the docs for the Protocol Buffers put message: > > http://docs.basho.com/riak/latest/references/apis/protocol-buffers/PBC-Store-Object/ When if_none_match is enabled, will riakc_pb_socket:put/3 return ok regardless of whether the value was stored? > >> * How will riakc_pb_socket:get/3 behave when queue_if_disconnected is >> enabled? Will it fail immediately if the socket is disconnected or >> block until it has reconnected? > > With queue_if_disconnected enabled, riakc_pb_socket:get/3 will block > until the socket is reconnected. > > HTH, > Bryan Regards, Alex _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
