完成查询优化：谓词下推、投影下推和常量折叠，配置好了benchmark

chusql-engine/app/Main.hs

@@ -1,24 +1,39 @@
 module Main where
 
-import ChuSQL.SQLSyntax.Executor
+import ChuSQL.Algebra.Op (RelOp (..))
+import ChuSQL.Algebra.Optimize (optimize)
+import ChuSQL.Algebra.Planner (translate)
 import ChuSQL.Model
 import ChuSQL.SQLSyntax.AST
+import ChuSQL.SQLSyntax.Executor
 import ChuSQL.SQLSyntax.Parser
 
 users :: Table
 users =
     Table
         { tableName = "users"
-        , tableCols = ["name", "age"]
+        , tableCols = ["id", "name", "age"]
         , tableRows =
-            [ [("name", VStr "Alice"), ("age", VInt 25)]
-            , [("name", VStr "Bob"), ("age", VInt 17)]
-            , [("name", VStr "Carol"), ("age", VInt 30)]
+            [ [("id", VInt 1), ("name", VStr "Alice"), ("age", VInt 25)]
+            , [("id", VInt 2), ("name", VStr "Bob"), ("age", VInt 17)]
+            , [("id", VInt 3), ("name", VStr "Carol"), ("age", VInt 30)]
+            ]
+        }
+
+orders :: Table
+orders =
+    Table
+        { tableName = "orders"
+        , tableCols = ["id", "user_id", "product"]
+        , tableRows =
+            [ [("id", VInt 1), ("user_id", VInt 1), ("product", VStr "Book")]
+            , [("id", VInt 2), ("user_id", VInt 2), ("product", VStr "Pen")]
+            , [("id", VInt 3), ("user_id", VInt 1), ("product", VStr "Cup")]
             ]
         }
 
 db :: Database
-db = [("users", users)]
+db = [("users", users), ("orders", orders)]
 
 -- runQuery 返回 (更新后的数据库, 结果行)；演示只关心结果行
 rowsOf :: Either String (Database, [Row]) -> Either String [Row]
@@ -26,6 +41,7 @@ rowsOf = fmap snd
 
 main :: IO ()
 main = do
+    putStrLn "==================== Parser Test ====================="
     let q1 = makeSelect ["name"] "users" (Just (Gt (Col "age") (LitInt 18)))
     print (rowsOf (runQuery db q1))
 
@@ -50,3 +66,42 @@ main = do
     -- 解析 SQL 文本，再交给执行引擎
     let parsed = parseQuery "SELECT name FROM users WHERE age > 18 AND name = 'Alice'"
     print (rowsOf (parsed >>= runQuery db))
+
+    putStrLn "\n==================== Optimizer ====================="
+    let planSql =
+            "SELECT u.name, o.product FROM users u \
+            \JOIN orders o ON u.id = o.user_id WHERE u.age > 18"
+    case parseQuery planSql of
+        Left err -> putStrLn err
+        Right query -> case translate db query of
+            Left err -> putStrLn err
+            Right plan -> do
+                putStrLn "--- plan before optimization ---"
+                putStrLn (dump 0 plan)
+                putStrLn "--- plan after optimization ---"
+                putStrLn (dump 0 (optimize db plan))
+                putStrLn "--- rows ---"
+                print (rowsOf (runQuery db query))
+
+dump :: Int -> RelOp -> String
+dump ind op = case op of
+    Scan a t ->
+        pad ++ "Scan " ++ show a ++ " " ++ show t
+    Filter e x ->
+        pad ++ "Filter " ++ show e ++ "\n" ++ dump (ind + 1) x
+    Project c x ->
+        pad ++ "Project " ++ show c ++ "\n" ++ dump (ind + 1) x
+    Sort s x ->
+        pad ++ "Sort " ++ show s ++ "\n" ++ dump (ind + 1) x
+    Limit n x ->
+        pad ++ "Limit " ++ show n ++ "\n" ++ dump (ind + 1) x
+    Join l r c ->
+        pad
+            ++ "Join on "
+            ++ show c
+            ++ "\n"
+            ++ dump (ind + 1) l
+            ++ "\n"
+            ++ dump (ind + 1) r
+  where
+    pad = replicate (ind * 2) ' '