macintux

1. pg_dump is a nifty utility designed to output a series of SQL statements that describes the schema and data of your database. You can control what goes into your backup by using additional flags.
   Backup: pg_dump -h localhost -p 5432 -U postgres -d mydb > backup.sql

   Restore: psql -h localhost -p 5432 -U postgres -d mydb < backup.sql

   -h is for host.
   -p is for port.
   -U is for username.
   -d is for database.

macintux

#!/usr/bin/env escript
% -*- mode: erlang -*-

main([BeamFile]) ->
    {ok,{_,[{abstract_code,{_,AC}}]}} = beam_lib:chunks(BeamFile,[abstract_code]),
    io:fwrite("~s~n", [erl_prettypr:format(erl_syntax:form_list(AC))]).

macintux

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

macintux

curl -XPOST http://localhost:8098/mapred
  -H"Content-Type: application/json"
  -d  '{"inputs":"notifications","query":[{"map":{"language":"erlang","source":"fun(O,_,_) when element(1,O) == r_object -> S=byte_size(term_to_binary(riak_object:get_values(O))), if (S>1048576) -> {ok,C}=riak:local_client(),C:delete(riak_object:bucket(O),riak_object:key(O)),[riak_object:key(O)]; true -> [] end;(_,_,_) -> [] end."}}]}'