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%% Get the state for the local node
%% The get_my_ring function really returns the ring
%% plus other state information about the cluster.
{ok, State} = riak_core_ring_manager:get_my_ring().

%% Get number of partitions
riak_core_ring:num_partitions(State).

%% Get the names of custom buckets
riak_core_ring:get_buckets(State).

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%% Get the state for the local node
%% The get_my_ring function really returns the ring
%% plus other state information about the cluster.
{ok, State} = riak_core_ring_manager:get_my_ring().

%% Get number of partitions
riak_core_ring:num_partitions(State).

%% Get the names of custom buckets
riak_core_ring:get_buckets(State).

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sample

• timeout(sec) : 5
• message count: 2

(riak1@127.0.0.1)14> redbug:start(5000, 2, {riak_kv_keys_fsm,'_'}).
ok

16:23:32 <{riak_core_coverage_fsm,init,1}> {riak_kv_keys_fsm,init,

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Erlang Tracing: more than you wanted to know

Rough Outline

• What can be traced?
• How can trace events be specified?
• "match specifications": twisty passages, all alike
• WTF, can I just use DTrace and drink my coffee/beer/whisky in peace?
• Trace delivery mechanisms: pick one of two

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10 Erlang one liners to impress your friends

1. Multiple Each Item in a List by 2:

---

[X * 2 || X <- lists:seq(1, 11)].

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Put

API

• Starting: https://github.com/basho/riak_kv/blob/1.4.2/src/riak_kv_wm_object.erl#L619
• We create a new riak_object and populate the various fields with the headers, metadata supplied by the client.
• Big suprise, we eventually call riak_client:put: https://github.com/basho/riak_kv/blob/1.4.2/src/riak_client.erl#L143
• If/when the client returns any errors these are handled in handle_common_errors and it is nice to return human readable errors to client :)

Riak_client

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Riak Source Code Reading #27: Riak KV backend API and storage

The Riak KV backend store API

behaviour_info(callbacks) ->
    [
     {api_version,0},

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echo "Data load start time: $(date +%s)"
for i in {1..100}
do
    curl -XPOST http://localhost:10018/riak/some_bucket -d "$RANDOM" -H "X-Riak-Index-Timestamp_int: $(date +%s)" -H "Content-Type: text/plain"
    sleep 0.5
done
echo "Data load end time: $(date +%s)"

echo "Running MapReduce"
curl -XPOST http://localhost:10018/mapred -H "Content-Type: application/json" -d '

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import scala.concurrent.duration._
import scala.concurrent.ExecutionContext
import scala.concurrent.Future
import akka.pattern.after
import akka.actor.Scheduler

/**
 * Given an operation that produces a T, returns a Future containing the result of T, unless an exception is thrown,
 * in which case the operation will be retried after _delay_ time, if there are more possible retries, which is configured through
 * the _retries_ parameter. If the operation does not succeed and there is no retries left, the resulting Future will contain the last failure.

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#!/usr/bin/env python
 
import httplib
import json
from datetime import datetime, date, time
from time import sleep
import os.path
from multiprocessing import Process