ast2sqlでviewのΔに対してinsert/deleteを出力しない #49

hiroshi-cl · 2024-09-18T08:00:14Z

概要

#46 (2-2)

ビューに対するΔ述語が残っているルールをdl2uする場合、ビューに対するΔ述語は通常の述語を同様な扱いにしてほしい。

を実現するパッチです

方針

通常 dl2u コマンド (ast2sql.ml) では、 -a のようなΔ述語のDatalog式に対して以下のような2行のSQLを出力する

CREATE TEMPORARY TABLE temp2 AS SELECT ...;
DELETE FROM a USING temp2 WHERE ...;

ここで、ビューに対するΔ述語のときはDELETEを出力したくないが、テンポラリテーブルの方は変わらず参照が必要とのことであった。
そこで、今回の対応では単純にΔ述語がビューに対するものかどうか判定して、ビューに対するもののときはDELETEの出力だけ抑制するようにする。
また　+ および INSERT についても同様に出力抑制の対応を行う。

没にした方針

head_spec, grouping_state, rule_group にビューに対するΔ述語のパターンを追加して状態を引き回す
没にした理由
- 引き回しにより変更行数が大きくなるため
- より簡単な方針が見つかったため
- 大改修するならrule abstractionなどを使うように書き直した方がいいと思われるため

例

#46 に示されている例を使う

入力 (dl2u_2-2.dl)

source a('A':int, 'B':int).
source b('B':int, 'C':int).
view v('A':int, 'B':int, 'C':int).
-a(A, B) :- a(A, B) , not __updated__v(A, B, _).
-b(B, C) :- a(GENV2, B) , b(B, C) , b(B, GENV3) , not -v(GENV2, B, GENV3) , not __updated__v(_, B, C).
__updated__v(A, B, C) :- a(A, B) , b(B, C) , not -v(A, B, C).
-v(GENV1, GENV2, GENV3) :- a(GENV1, GENV2) , b(GENV2, GENV3) , GENV2 = 30.

実行コマンド

dune exec dl2u examples/dl2u_2-2.dl

望ましい出力例

CREATE TEMPORARY TABLE mv AS SELECT a_0.A AS A, 30 AS B, b_1.C AS C FROM a AS a_0, b AS b_1 WHERE a_0.B = 30 AND b_1.B = 30;
CREATE TEMPORARY TABLE __updated__v AS SELECT a_0.A AS A, a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND NOT EXISTS ( SELECT * FROM mv AS t WHERE t.A = a_0.A AND t.B = a_0.B AND t.C = b_1.C );
CREATE TEMPORARY TABLE temp0 AS SELECT a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1, b AS b_2 WHERE b_1.B = a_0.B AND b_2.B = a_0.B AND NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.B = a_0.B AND t.C = b_1.C ) AND NOT EXISTS ( SELECT * FROM mv AS t WHERE t.A = a_0.A AND t.B = a_0.B AND t.C = b_2.C );
CREATE TEMPORARY TABLE temp1 AS SELECT a_0.A AS A, a_0.B AS B FROM a AS a_0 WHERE NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.A = a_0.A AND t.B = a_0.B );
DELETE FROM b USING temp0 WHERE b.B = temp0.B AND b.C = temp0.C;
DELETE FROM a USING temp1 WHERE a.A = temp1.A AND a.B = temp1.B;

出力

CREATE TEMPORARY TABLE temp0 AS SELECT a_0.A AS A, 30 AS B, b_1.C AS C FROM a AS a_0, b AS b_1 WHERE a_0.B = 30 AND b_1.B = 30;
CREATE TEMPORARY TABLE __updated__v AS SELECT a_0.A AS A, a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND NOT EXISTS ( SELECT * FROM temp0 AS t WHERE t.A = a_0.A AND t.B = a_0.B AND t.C = b_1.C );
CREATE TEMPORARY TABLE temp1 AS SELECT a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1, b AS b_2 WHERE b_1.B = a_0.B AND b_2.B = a_0.B AND NOT EXISTS ( SELECT * FROM temp0 AS t WHERE t.A = a_0.A AND t.B = a_0.B AND t.C = b_2.C ) AND NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.B = a_0.B AND t.C = b_1.C );
CREATE TEMPORARY TABLE temp2 AS SELECT a_0.A AS A, a_0.B AS B FROM a AS a_0 WHERE NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.A = a_0.A AND t.B = a_0.B );
DELETE FROM b USING temp1 WHERE b.B = temp1.B AND b.C = temp1.C;
DELETE FROM a USING temp2 WHERE a.A = temp2.A AND a.B = temp2.B;

望ましい例では temp0 -> mv, temp1 -> temp0, temp2 -> temp1 とリネームされていたが、改修前と同じテンポラリテーブル名をそのまま使っている

src/ast2sql.ml

hiroshi-cl · 2024-09-18T08:04:07Z

src/ast2sql.ml

@@ -2505,6 +2505,7 @@ let convert_expr_to_operation_based_sql (expr : expr) : (sql_operation list, err
      table_env |> TableEnv.add table cols
    ) TableEnv.empty
  in
+  let (view_name, _) = get_view expr in


view_nameを取得

src/ast2sql.ml

hiroshi-cl · 2024-09-18T12:30:11Z

src/ast2sql.ml

@@ -2559,7 +2560,7 @@ let convert_expr_to_operation_based_sql (expr : expr) : (sql_operation list, err
        get_column_names_from_table ~error_detail:(InGroup delta_key) table_env table >>= fun cols ->
        let delta_env = delta_env |> DeltaEnv.add delta_key (temporary_table, cols) in
        let creation = SqlCreateTemporaryTable (temporary_table, sql_query) in
-        if TableSet.mem table existent_tables then
+        if Option.fold ~none:true ~some:((<>) table) view_name && TableSet.mem table existent_tables then


viewに対するΔ述語だったら除外

hiroshi-cl · 2024-09-18T12:30:28Z

src/ast2sql.ml

@@ -2505,6 +2505,7 @@ let convert_expr_to_operation_based_sql (expr : expr) : (sql_operation list, err
      table_env |> TableEnv.add table cols
    ) TableEnv.empty
  in
+  let view_name = expr.view |> Option.map (fun (view_name, _) -> view_name) in


yoshihiro503 · 2024-09-26T01:41:53Z

@hiroshi-cl
加藤さんからご指摘いただきました。

dl2uの修正(2-2)のPR49についてですが、少し複雑な例で試してみたところ、正しくなさそうな変換をしているようです。
以下の例を実行してみました。
dune exec dl2u inlining_j.dl > inlining_j_new.sql
inlining_j.dlには+bをheadとするルールが二つあるにも関わらず
変換後のinlining_j.sqlにはINSERT bがありません。
また、inlining_j.dlには、+aをheadとするルールが二つありますが一つ目のルールしか対応していないようです。
それと、+vに関するルール
+v(GENV1, GENV2, GENV3) :- GENV1 = 4 , a(GENV1_2, GENV2) , b(GENV2, GENV3) , GENV3 = 3 , GENV1_2 <> 4.
は、まさに昨日の例
tmp(A, B, C) :- a(A, G) , b(G, C) , B = 60 , G = 30.
と同様のルールで、適切にSQLに変換されていることを確認しました。

inlining_j_new.sql.txt
inlining_j.dl.txt

hiroshi-cl · 2024-10-01T14:26:50Z

inlining_j.dlには+bをheadとするルールが二つあるにも関わらず
変換後のinlining_j.sqlにはINSERT bがありません。
また、inlining_j.dlには、+aをheadとするルールが二つありますが一つ目のルールしか対応していないようです。

こちらの1, 2番目の指摘事項なのですが、HEADでも起きていることなのでこのPRによるものではなさそうです。
HEADでdl2uを実行すると以下のようになりました。
別PRでの調査・修正対応とさせていただけるとありがたいです。

CREATE TEMPORARY TABLE temp0 AS SELECT a_0.A AS A, a_0.B AS B, 3 AS C FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND b_1.C = 3 AND a_0.A <> 4;
CREATE TEMPORARY TABLE __updated__v AS SELECT a_0.A AS A, a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND NOT EXISTS ( SELECT * FROM temp0 AS t WHERE t.A = a_0.A AND t.B = a_0.B AND t.C = b_1.C ) UNION SELECT 4 AS A, a_0.B AS B, 3 AS C FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND b_1.C = 3 AND a_0.A <> 4;
CREATE TEMPORARY TABLE temp1 AS SELECT 4 AS A, a_0.B AS B FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND b_1.C = 3 AND a_0.A <> 4 AND NOT EXISTS ( SELECT * FROM a AS t WHERE t.A = 4 AND t.B = a_0.B );
CREATE TEMPORARY TABLE temp2 AS SELECT a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1, b AS b_2 WHERE b_1.B = a_0.B AND b_2.B = a_0.B AND NOT EXISTS ( SELECT * FROM temp0 AS t WHERE t.A = a_0.A AND t.B = a_0.B AND t.C = b_2.C ) AND NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.B = a_0.B AND t.C = b_1.C ) UNION SELECT a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1, b AS b_2 WHERE b_1.B = a_0.B AND b_2.B = a_0.B AND b_2.C = 3 AND a_0.A <> 4 AND NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.B = a_0.B AND t.C = b_1.C );
CREATE TEMPORARY TABLE temp3 AS SELECT a_0.A AS A, a_0.B AS B FROM a AS a_0 WHERE NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.A = a_0.A AND t.B = a_0.B );
DELETE FROM v USING temp0 WHERE v.A = temp0.A AND v.B = temp0.B AND v.C = temp0.C;
INSERT INTO a SELECT * FROM temp1;
DELETE FROM b USING temp2 WHERE b.B = temp2.B AND b.C = temp2.C;
DELETE FROM a USING temp3 WHERE a.A = temp3.A AND a.B = temp3.B;

hiroyukikato · 2024-10-01T23:18:30Z

別PRでのご対応とのこと、よろしくお願いいたします。

hiroshi-cl · 2024-10-06T15:07:52Z

+CREATE TEMPORARY TABLE temp1 AS SELECT 4 AS A, a_0.B AS B, 3 AS C FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND b_1.C = 3 AND a_0.A <> 4;

意図しない差分があったので調査していたのですが、 #47 が未反映だったためでした

hiroshi-cl · 2024-10-07T14:36:46Z

HEADを取り込んだ後の差分

 CREATE TEMPORARY TABLE temp1 AS SELECT 4 AS A, a_0.B AS B FROM a AS a_0, b AS b_1 WHERE b_1.B = a_0.B AND b_1.C = 3 AND a_0.A <> 4 AND NOT EXISTS ( SELECT * FROM a AS t WHERE t.A = 4 AND t.B = a_0.B );
 CREATE TEMPORARY TABLE temp2 AS SELECT a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1, b AS b_2 WHERE b_1.B = a_0.B AND b_2.B = a_0.B AND NOT EXISTS ( SELECT * FROM temp0 AS t WHERE t.A = a_0.A AND t.B = a_0.B AND t.C = b_2.C ) AND NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.B = a_0.B AND t.C = b_1.C ) UNION SELECT a_0.B AS B, b_1.C AS C FROM a AS a_0, b AS b_1, b AS b_2 WHERE b_1.B = a_0.B AND b_2.B = a_0.B AND b_2.C = 3 AND a_0.A <> 4 AND NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.B = a_0.B AND t.C = b_1.C );
 CREATE TEMPORARY TABLE temp3 AS SELECT a_0.A AS A, a_0.B AS B FROM a AS a_0 WHERE NOT EXISTS ( SELECT * FROM __updated__v AS t WHERE t.A = a_0.A AND t.B = a_0.B );
-DELETE FROM v USING temp0 WHERE v.A = temp0.A AND v.B = temp0.B AND v.C = temp0.C;
 INSERT INTO a SELECT * FROM temp1;
 DELETE FROM b USING temp2 WHERE b.B = temp2.B AND b.C = temp2.C;
 DELETE FROM a USING temp3 WHERE a.A = temp3.A AND a.B = temp3.B;

hiroyukikato · 2024-10-24T03:22:27Z

Thanks! LGTM

add example

09e2f54

hiroshi-cl self-assigned this Sep 18, 2024