Use IO lists to build insert events SQL statement

Fixes #23.

bench/storage/append_events_bench.exs

@@ -5,7 +5,6 @@ defmodule AppendEventsBench do
   alias EventStore.Storage
 
   setup_all do
-    Code.require_file("event_factory.ex", "test")
     Application.ensure_all_started(:eventstore)
   end
 

bench/storage/read_events_bench.exs

@@ -5,7 +5,6 @@ defmodule ReadEventsBench do
   alias EventStore.Storage
 
   setup_all do
-    Code.require_file("event_factory.ex", "test")
     Application.ensure_all_started(:eventstore)
   end
 

config/bench.exs

@@ -7,4 +7,6 @@ config :eventstore, EventStore.Storage,
   username: "postgres",
   password: "postgres",
   database: "eventstore_bench",
-  hostname: "localhost"
+  hostname: "localhost",
+  pool_size: 10,
+  extensions: [{Postgrex.Extensions.Calendar, []}]

lib/event_store/sql/statements.ex

@@ -119,17 +119,32 @@ RETURNING stream_id;
   end
 
   def create_events(number_of_events \\ 1) do
-    insert = "INSERT INTO events (event_id, stream_id, stream_version, correlation_id, event_type, data, metadata, created_at) VALUES"
+    insert = ["INSERT INTO events (event_id, stream_id, stream_version, correlation_id, event_type, data, metadata, created_at) VALUES"]
 
     params =
       1..number_of_events
       |> Enum.map(fn event_number ->
         index = (event_number - 1) * 8
-        "($#{index + 1}, $#{index + 2}, $#{index + 3}, $#{index + 4}, $#{index + 5}, $#{index + 6}, $#{index + 7}, $#{index + 8})"
+        event_params = [
+          "($",
+          Integer.to_string(index + 1), ", $",
+          Integer.to_string(index + 2), ", $",
+          Integer.to_string(index + 3), ", $",
+          Integer.to_string(index + 4), ", $",
+          Integer.to_string(index + 5), ", $",
+          Integer.to_string(index + 6), ", $",
+          Integer.to_string(index + 7), ", $",
+          Integer.to_string(index + 8), ")"
+        ]
+
+        if event_number == number_of_events do
+          event_params
+        else
+          [event_params, ","]
+        end
       end)
-      |> Enum.join(",")
 
-    insert <> " " <> params <> ";"
+    [insert, " ", params, ";"]
   end
 
   def create_subscription do

lib/event_store/storage/appender.ex

@@ -30,7 +30,7 @@ defmodule EventStore.Storage.Appender do
 
   defp build_insert_parameters(events) do
     events
-    |> Enum.map(fn(event) ->
+    |> Enum.flat_map(fn event ->
       [
         event.event_id,
         event.stream_id,
@@ -42,7 +42,6 @@ defmodule EventStore.Storage.Appender do
         event.created_at,
       ]
     end)
-    |> List.flatten
   end
 
   defp handle_response({:ok, %Postgrex.Result{num_rows: 0}}, stream_id) do

mix.exs

@@ -31,6 +31,7 @@ defmodule EventStore.Mixfile do
   end
 
   defp elixirc_paths(:test), do: ["lib", "test/support"]
+  defp elixirc_paths(:bench), do: ["lib", "test/support"]
   defp elixirc_paths(_), do: ["lib"]
 
   defp deps do
@@ -42,7 +43,7 @@ defmodule EventStore.Mixfile do
       {:fsm, "~> 0.2"},
       {:markdown, github: "devinus/markdown", only: :dev},
       {:mix_test_watch, "~> 0.2", only: :dev},
-      {:poison, "~> 3.0", only: :test},
+      {:poison, "~> 3.0", only: [:bench, :test]},
       {:poolboy, "~> 1.5"},
       {:postgrex, "~> 0.12"},
       {:uuid, "~> 1.1", only: [:bench, :test]}
@@ -68,7 +69,8 @@ EventStore using PostgreSQL for persistence.
   defp aliases do
     [
       "es.setup": ["event_store.create"],
-      "es.reset": ["event_store.drop", "event_store.create"]
+      "es.reset": ["event_store.drop", "event_store.create"],
+      "benchmark": ["es.reset", "app.start", "bench"],
     ]
   end
 end