CouchDB(btree) vs dets.

couchdb_btree_vs_dets.erl

-module(couchdb_btree_vs_dets).
-author('cooldaemon@gmail.com').

-export([test/0, test/1]).

test() -> test(1000).
test(Count) ->
  KVs = lists:map(
    fun (N) -> {N, {foo, bar, baz}} end,
    lists:seq(1, Count)
  ),
  lists:foreach(
    fun ({F, TargetName}) ->
      {[SetRunTime, SetWallClock], [GetRunTime, GetWallClock]} = F(KVs),
      io:fwrite(
        "--<~s>--~nset:~p(~p)ms~nget:~p(~p)ms~n",
        [TargetName, SetRunTime, SetWallClock, GetRunTime, GetWallClock]
      )
    end,
    [
      {fun dets/1,  "dets"},
      {fun btree1/1, "CouchDB B-Tree(case1)"},
      {fun btree2/1, "CouchDB B-Tree(case2)"},
      {fun btree3/1, "CouchDB B-Tree(case3)"},
      {fun btree4/1, "CouchDB B-Tree(case4)"}
    ]
  ).

dets(KVs) ->
  {ok, _R} = dets:open_file(dets_test, []),
  {_SetResult, SetTimes} = benchmark(
    fun () ->
      lists:foreach(fun (KV) -> dets:insert(dets_test, KV) end, KVs)
    end
  ),
  {_GetResult, GetTimes} = benchmark(
    fun () ->
      lists:map(
        fun ({K, _}) -> dets:lookup(dets_test, K) end, KVs
      )
    end
  ),
  {SetTimes, GetTimes}.

btree_open(FileName) ->
  {ok, Fd} = couch_file:open(FileName, [create, overwrite]),
  {ok, Bt} = couch_btree:open(nil, Fd),
  Bt.

btree_bulk_set(Bt, KVs) ->
  {{ok, NewBt}, SetTimes} = benchmark(
    fun () -> couch_btree:add(Bt, KVs) end
  ),
  {NewBt, SetTimes}.

btree_bulk_get(Bt, KVs) ->
  Ks = lists:map(fun ({K, _V}) -> K end, KVs),
  {_GetResult, GetTimes} = benchmark(
    fun () -> couch_btree:lookup(Bt, Ks) end
  ),
  GetTimes.

btree_set(Bt, KVs) ->
  {{ok, NewBt}, SetTimes} = benchmark(
    fun () ->
      lists:foldl(
        fun (KV, {ok, TmpBt}) -> couch_btree:add(TmpBt, [KV]) end,
        {ok, Bt}, KVs
      )
    end
  ),
  {NewBt, SetTimes}.

btree_get(Bt, KVs) ->
  Ks = lists:map(fun ({K, _V}) -> K end, KVs),
  {_GetResult, GetTimes} = benchmark(
    fun () -> lists:map(fun (N) -> couch_btree:lookup(Bt, [N]) end, Ks) end
  ),
  GetTimes.
 
btree(KVs, FileName, SetFunc, GetFunc) ->
  Bt = btree_open(FileName),
  {NewBt, SetTimes} = SetFunc(Bt, KVs),
  GetTimes = GetFunc(NewBt, KVs),
  {SetTimes, GetTimes}.

btree1(KVs) ->
  btree(KVs, "btree1_test", fun btree_bulk_set/2, fun btree_bulk_get/2).

btree2(KVs) ->
  btree(KVs, "btree2_test", fun btree_set/2, fun btree_get/2).

btree3(KVs) ->
  btree(KVs, "btree3_test", fun btree_set/2, fun btree_bulk_get/2).

btree4(KVs) ->
  btree(KVs, "btree4_test", fun btree_bulk_set/2, fun btree_get/2).

benchmark(TargetFunction) ->
  lists:foreach(fun statistics/1, [runtime, wall_clock]),
  Result = TargetFunction(),
  Times = lists:map(
    fun (Type) -> {_, T} = statistics(Type), T end,
    [runtime, wall_clock]
  ),
  {Result, Times}.