russelldb

1> {ok, Pid} = riakc_pb_socket:start_link("localhost", 8087).
{ok,<0.35.0>}
2> riakc_pb_socket:set_bucket(Pid, <<"foo">>, [{allow_mult, true}]).
ok
3> riakc_pb_socket:counter_incr(Pid, <<"foo">>, <<"bar">>, 1).      
ok
4> riakc_pb_socket:counter_incr(Pid, <<"foo">>, <<"bar">>, 3).
ok
5> riakc_pb_socket:counter_incr(Pid, <<"foo">>, <<"bar">>, -2).
ok

russelldb

Here's where I understand the state of the art to be:

• In this INRIA tech report, Shapiro, Preguiça, Baquero and Zawirski (SPBZ) prove, amongst other things, that a sufficient condition for CRDTs to achieve eventual consistency on networks which may reorder and duplicate packets (which I'll call flaky networks, henceforth) is that
  1. the underlying datatype forms a semilattice,
  2. messages are full states,
  3. incoming messages are combined with the node's current state using the least-upper-bound operation in the semilattice.
• It's possible to relax condition 2 and still achieve eventual consistency over flaky networks by fragmenting the state into independent parts and transmitting updates to each part separately. For instance, in the G-Set CRDT (an add-only bitset) one can transmit only the index of the element to be added.
• In [these slides from a talk at Dagstuhl](http://www.dagstuhl.de/mat/Files/13/13081/13081.BaqueroCarlos.Sl

russelldb

CvRDTs are (almost?) as general as they can be

What are you talking about, and why should I care?

Now that we live in the Big Data, Web 3.14159 era, lots of people want to build databases that are too big to fit on a single machine. But there's a problem in the form of the CAP theorem, which states that if your network ever partitions (a machine goes down, or part of the network loses its connection to the rest) then you can keep consistency (all machines return the same answer to

russelldb

{set,{var,1},{call,crdt_statem_eqc,create,[riak_dt_multi]}},
 {set,{var,2},
      {call,crdt_statem_eqc,merge,[riak_dt_multi,{0,{var,1}},{0,{var,1}}]}},
 {set,{var,3},
      {call,crdt_statem_eqc,merge,[riak_dt_multi,{0,{var,2}},{0,{var,2}}]}},
 {set,{var,4},
      {call,crdt_statem_eqc,update,
            [riak_dt_multi,
             {update,[{update,{<<>>,riak_dt_vvorset},{add_all,[]}}]},
             {0,{var,3}}]}},

russelldb

Node 'riak@127.0.0.1' not responding to pings.
bad -z option -zdss
Usage: beam.smp [flags] [ -- [init_args] ]
The flags are:

-a size     suggested stack size in kilo words for threads
            in the async-thread pool, valid range is [16-8192]
-A number   set number of threads in async thread pool,
            valid range is [0-1024]
-B[c|d|i]   c to have Ctrl-c interrupt the Erlang shell,

russelldb

Locate the section for your github remote in the .git/config file. It looks like this:

[remote "origin"]
	fetch = +refs/heads/*:refs/remotes/origin/*
	url = git@github.com:joyent/node.git

Now add the line fetch = +refs/pull/*/head:refs/remotes/origin/pr/* to this section. Obviously, change the github url to match your project's URL. It ends up looking like this:

russelldb

Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [hipe] [kernel-poll:false]

Eshell V5.9.1  (abort with ^G)
1> erlang:system_info(cpu_topology).                               
undefined
2> 

russelldb

Erlang R14B04 (erts-5.8.5) [source] [64-bit] [smp:12:12] [rq:12] [async-threads:0] [kernel-poll:false]

Eshell V5.8.5  (abort with ^G)
1> erlang:system_info(cpu_topology).
[{processor,[{core,[{thread,{logical,0}},
                    {thread,{logical,6}}]},
             {core,[{thread,{logical,1}},{thread,{logical,7}}]},
             {core,[{thread,{logical,2}},{thread,{logical,8}}]},
             {core,[{thread,{logical,3}},{thread,{logical,9}}]},
             {core,[{thread,{logical,4}},{thread,{logical,10}}]},

russelldb

Erlang R15B01 (erts-5.9.1) [source] [64-bit] [smp:4:4] [async-threads:0] [kernel-poll:false]

Eshell V5.9.1  (abort with ^G)
1> erlang:system_info(cpu_topology).
[{processor,[{core,{logical,0}},
             {core,{logical,1}},
             {core,{logical,2}},
             {core,{logical,3}}]}]
2> 

russelldb

(riak@127.0.0.1)1> {ok, C} = riak:local_client().
{ok,{riak_client,'riak@127.0.0.1',undefined}}
(riak@127.0.0.1)2> Object = riak_object:new(<<"testbucket">>, <<"testkey">>, <<"testvalue">>).
{r_object,<<"testbucket">>,<<"testkey">>,
          [{r_content,{dict,0,16,16,8,80,48,
                            {[],[],[],[],[],[],[],[],[],[],[],[],[],[],...},
                            {{[],[],[],[],[],[],[],[],[],[],[],[],...}}},
                      <<"testvalue">>}],
          [],
          {dict,1,16,16,8,80,48,