Optimize SQL generation

Author: Schultzer

bench.exs

@@ -1,10 +1,21 @@
 import SQL
+import Ecto.Query
+defmodule SQL.Repo do
+  use Ecto.Repo, otp_app: :sql, adapter: Ecto.Adapters.Postgres
+end
+Application.put_env(:sql, :ecto_repos, [SQL.Repo])
+Application.put_env(:sql, SQL.Repo, username: "postgres", password: "postgres", hostname: "localhost", database: "sql_test#{System.get_env("MIX_TEST_PARTITION")}", pool: Ecto.Adapters.SQL.Sandbox, pool_size: 10)
+SQL.Repo.start_link()
+
 range = 1..10_000
+sql = ~SQL[with recursive temp (n, fact) as (select 0, 1 union all select n+1, (n+1)*fact from temp where n < 9)]
+query = "temp" |> recursive_ctes(true) |> with_cte("temp", as: ^union_all(select("temp", [t], %{n: 0, fact: 1}), ^where(select("temp", [t], [t.n+1, t.n+1*t.fact]), [t], t.n < 9))) |> select([t], [t.n])
 Benchee.run(
   %{
-    "to_stirng" => fn -> for _ <- range, do: to_string(~SQL[with recursive temp (n, fact) as (select 0, 1 union all select n+1, (n+1)*fact from temp where n < 9)]) end,
-    "to_sql" => fn -> for _ <- range, do: SQL.to_sql(~SQL[with recursive temp (n, fact) as (select 0, 1 union all select n+1, (n+1)*fact from temp where n < 9)]) end,
-    "inspect" => fn -> for _ <- range, do: inspect(~SQL[with recursive temp (n, fact) as (select 0, 1 union all select n+1, (n+1)*fact from temp where n < 9)]) end
+    "to_stirng" => fn -> for _ <- range, do: to_string(sql) end,
+    "to_sql" => fn -> for _ <- range, do: SQL.to_sql(sql) end,
+    "inspect" => fn -> for _ <- range, do: inspect(sql) end,
+    "Ecto.Repo.to_sql" => fn -> for _ <- range, do: SQL.Repo.to_sql(:all, query) end
   },
   time: 10,
   memory_time: 2

lib/sql.ex

@@ -38,7 +38,7 @@ defmodule SQL do
       {"select id, email from users where email = $0", ["[email protected]"]}
   """
   @doc since: "0.1.0"
-  def to_sql(sql), do: {"#{sql}", sql.params}
+  def to_sql(sql), do: {sql.string, sql.params}
 
   @doc false
   def build(right, {:<<>>, meta, _} = left, _modifiers, env) do
@@ -49,9 +49,11 @@ defmodule SQL do
         {v, 0}, {tokens, params} -> {tokens ++ v.tokens, params ++ v.params}
         end)
       {:ok, opts, _, _, _, _, tokens} = SQL.Lexer.lex(left, binding(), meta, p)
-      t ++ SQL.Parser.parse(tokens)
+      sql = t ++ SQL.Parser.parse(tokens)
       |> SQL.to_query()
       |> Map.merge(%{module: __MODULE__, params: opts[:params]})
+
+      Map.put(sql, :string, to_string(sql))
     end
   end
 
@@ -108,6 +110,9 @@ defmodule SQL do
   end
 
   defimpl String.Chars, for: SQL do
+    def to_string(%{string: string}) do
+      string
+    end
     def to_string(sql) do
       cond do
         Kernel.function_exported?(sql.module, :config, 0) -> Enum.map(sql.query, &sql.module.config()[:adapter].token_to_string(&1))