[tarantool-patches] Re: [PATCH] sql: fix fk set null clause
Alex Khatskevich
avkhatskevich at tarantool.org
Thu Oct 11 16:20:25 MSK 2018
>> After changing behavior of the `IS` operator (#b3a3ddb571),
>> `SET NULL` was rewritten to use `EQ` instead. Which do not respect
> Nit: doesn’t.
fixed
>> NULLs.
>>
>> This commit fixes the null related behavior by emitting logical
>> constructions equivalent for this case to old `IS`.
>> Those constructions are not equal to the old `EQ` in common case.
>> Before:
>> `oldval` old_is `newval`
>> Now:
>> `oldval` is_null or (`newval` is_not_null and `oldval` eq `newval`)
> I guess it is not completely correct: if oldval == NULL and newval != NULL,
> than ‘before’ condition will be false, but ’now’ will be true. Did I miss smth?
Yes. Those are equivalent for that particular case. I slightly updated
the comment.
New comment:
====
This commit fixes the null related behavior by emitting logical
constructions equivalent for this case to old `IS`.
The new expression works differently than old `IS` for nulls, however
the difference doesn't change anything, because matched rows are then
searched in a child table with `EQ` expression which do not match nulls.
Before:
`oldval` old_is `newval`
Now:
`oldval` is_null or (`newval` is_not_null and `oldval` eq `newval`)
=====
>> Closes #3645
>> ---
>> Issue: https://github.com/tarantool/tarantool/issues/3645
>> Branch: https://github.com/tarantool/tarantool/tree/kh/gh-3642-set-null
>>
>> src/box/sql/fkey.c | 49 ++++++++++++++------
>> test/sql-tap/gh3645-set-null.test.lua | 84 +++++++++++++++++++++++++++++++++++
>> 2 files changed, 119 insertions(+), 14 deletions(-)
>> create mode 100755 test/sql-tap/gh3645-set-null.test.lua
>>
>> diff --git a/src/box/sql/fkey.c b/src/box/sql/fkey.c
>> index 091778fc8..0abf42c84 100644
>> --- a/src/box/sql/fkey.c
>> +++ b/src/box/sql/fkey.c
>> @@ -787,24 +787,45 @@ fkey_action_trigger(struct Parse *pParse, struct Table *pTab, struct fkey *fkey,
>>
>> /*
>> * For ON UPDATE, construct the next term of the
>> - * WHEN clause. The final WHEN clause will be like
>> + * WHEN clause, which should return false in case
>> + * there is a reason to for a broken constrant in
>> + * a parent table:
>> + * no_action_needed := `oldval` IS NULL OR
>> + * (`newval` IS NOT NULL AND
>> + * `newval` = `oldval`)
>> + *
>> + * The final WHEN clause will be like
>> * this:
>> *
>> - * WHEN NOT(old.col1 = new.col1 AND ... AND
>> - * old.colN = new.colN)
>> + * WHEN NOT( no_action_needed(col1) AND ...
>> + * no_action_needed(colN))
>> */
>> if (is_update) {
>> - struct Expr *l, *r;
>> - l = sqlite3PExpr(pParse, TK_DOT,
>> - sqlite3ExprAlloc(db, TK_ID, &t_old, 0),
>> - sqlite3ExprAlloc(db, TK_ID, &t_to_col,
>> - 0));
>> - r = sqlite3PExpr(pParse, TK_DOT,
>> - sqlite3ExprAlloc(db, TK_ID, &t_new, 0),
>> - sqlite3ExprAlloc(db, TK_ID, &t_to_col,
>> - 0));
>> - eq = sqlite3PExpr(pParse, TK_EQ, l, r);
>> - when = sqlite3ExprAnd(db, when, eq);
>> + Expr *old_val = sqlite3PExpr(
> Nit: struct Expr *...
>
>> + pParse, TK_DOT,
>> + sqlite3ExprAlloc(db, TK_ID, &t_old, 0),
>> + sqlite3ExprAlloc(db, TK_ID, &t_to_col,
>> + 0));
>> + Expr *newVal = sqlite3PExpr(
> Nit: struct Expr new_val = …
> And use everywhere else ‘struct' prefix.
>
>> + pParse, TK_DOT,
>> + sqlite3ExprAlloc(db, TK_ID, &t_new, 0),
>> + sqlite3ExprAlloc(db, TK_ID, &t_to_col,
>> + 0));
>> + Expr *old_is_null = sqlite3PExpr(
>> + pParse, TK_ISNULL,
>> + sqlite3ExprDup(db, old_val, 0), NULL);
>> + eq = sqlite3PExpr(
>> + pParse, TK_EQ,
>> + sqlite3ExprDup(db, old_val, 0),
>> + sqlite3ExprDup(db, newVal, 0));
>> + Expr *new_non_null = sqlite3PExpr(
>> + pParse, TK_NOTNULL, newVal, NULL);
>> + Expr *non_null_eq = sqlite3PExpr(
>> + pParse, TK_AND, new_non_null, eq);
>> + Expr *no_action_needed = sqlite3PExpr(
>> + pParse, TK_OR, old_is_null,
>> + non_null_eq);
>> + when = sqlite3ExprAnd(db, when, no_action_needed);
> How memory for old_val will be released? It’s twice dupped, but original
> value will be not freed. new_val is once dupped and once used, for example.
> I guess it looks like leak.
Yes, it is.
>
> Overall, I suggest cosmetic diff (indentation + struct prefixes):
>
> +++ b/src/box/sql/fkey.c
> @@ -801,30 +801,24 @@ fkey_action_trigger(struct Parse *pParse, struct Table *pTab, struct fkey *fkey,
> * no_action_needed(colN))
> */
> if (is_update) {
> - Expr *old_val = sqlite3PExpr(
> - pParse, TK_DOT,
> + struct Expr *old_val = sqlite3PExpr(pParse, TK_DOT,
> sqlite3ExprAlloc(db, TK_ID, &t_old, 0),
> - sqlite3ExprAlloc(db, TK_ID, &t_to_col,
> - 0));
> - Expr *newVal = sqlite3PExpr(
> - pParse, TK_DOT,
> + sqlite3ExprAlloc(db, TK_ID, &t_to_col, 0));
> + struct Expr *new_val = sqlite3PExpr(pParse, TK_DOT,
> sqlite3ExprAlloc(db, TK_ID, &t_new, 0),
> - sqlite3ExprAlloc(db, TK_ID, &t_to_col,
> - 0));
> - Expr *old_is_null = sqlite3PExpr(
> - pParse, TK_ISNULL,
> + sqlite3ExprAlloc(db, TK_ID, &t_to_col, 0));
> + struct Expr *old_is_null = sqlite3PExpr(pParse, TK_ISNULL,
> sqlite3ExprDup(db, old_val, 0), NULL);
> - eq = sqlite3PExpr(
> - pParse, TK_EQ,
> - sqlite3ExprDup(db, old_val, 0),
> - sqlite3ExprDup(db, newVal, 0));
> - Expr *new_non_null = sqlite3PExpr(
> - pParse, TK_NOTNULL, newVal, NULL);
> - Expr *non_null_eq = sqlite3PExpr(
> - pParse, TK_AND, new_non_null, eq);
> - Expr *no_action_needed = sqlite3PExpr(
> - pParse, TK_OR, old_is_null,
> - non_null_eq);
> + eq = sqlite3PExpr(pParse, TK_EQ,
> + sqlite3ExprDup(db, old_val, 0),
> + sqlite3ExprDup(db, new_val, 0));
> + struct Expr *new_non_null =
> + sqlite3PExpr(pParse, TK_NOTNULL, new_val, NULL);
> + struct Expr *non_null_eq =
> + sqlite3PExpr(pParse, TK_AND, new_non_null, eq);
> + struct Expr *no_action_needed =
> + sqlite3PExpr(pParse, TK_OR, old_is_null,
> + non_null_eq);
applied.
>> }
>>
>> if (action != FKEY_ACTION_RESTRICT &&
>> diff --git a/test/sql-tap/gh3645-set-null.test.lua b/test/sql-tap/gh3645-set-null.test.lua
>> new file mode 100755
>> index 000000000..9067c52f1
>> --- /dev/null
>> +++ b/test/sql-tap/gh3645-set-null.test.lua
> I wouldn’t create separate test-file for this ticket: you could
> use one of fkey1-4 test suites.
moved
>
>> @@ -0,0 +1,84 @@
>> +#!/usr/bin/env tarantool
>> +test = require("sqltester")
>> +test:plan(11)
>> +
>> +test:do_catchsql_test(
>> + "set-null-1.0",
>> + [[
>> + CREATE TABLE T1 (a INTEGER PRIMARY KEY,
>> + b char(5) unique);
>> + CREATE TABLE T2 (a INTEGER PRIMARY KEY,
>> + b char(5) unique,
>> + foreign key (b) references t1 (b) on update set null);
> Nit: use uppercase for SQL keywords.
done
>
>> + INSERT INTO T1 VALUES (1,'a');
>> + INSERT INTO T2 VALUES (1,'a’);
> Nit: indentation is broken.
fixed
>
>> + ]], {0});
>> +
>> +test:do_catchsql_test(
>> + "set-null-1.1",
>> + [[
>> + UPDATE T1 SET B = NULL;
>> + ]], {0});
>> +
>> +test:do_catchsql_test(
> Why do you use catchsql? I guess execsql would be more suitable here
> and for the rest tests as well (except for UPDATE statements).
fixed
>
>> +test:do_catchsql_test(
>> + "set-null-2.0",
>> + [[
>> + CREATE TABLE T3 (a INTEGER PRIMARY KEY,
>> + b char(5) unique);
>> + CREATE TABLE T4 (a INTEGER PRIMARY KEY,
>> + b char(5) unique,
>> + foreign key (b) references t3 (b) on update cascade);
>> + INSERT INTO T3 VALUES (1,'a');
>> + INSERT INTO T4 VALUES (1,'a');
>> + ]], {0});
> Indentation is broken.
> How ‘ON UPDATE CASCADE’ clause is related to ’SET NULL’?
Not related. Similar test exists. Deleted.
New diff:
commit 77d76c1c664f992efc54b5a3329a44a185b1e4cf
Author: AKhatskevich <avkhatskevich at tarantool.org>
Date: Mon Oct 8 19:26:59 2018 +0300
sql: fix fk set null clause
After changing behavior of the `IS` operator (#b3a3ddb571),
`SET NULL` was rewritten to use `EQ` instead. Which doesn't respect
NULLs.
This commit fixes the null related behavior by emitting logical
constructions equivalent for this case to old `IS`.
The new expression works differently than old `IS` for nulls, however
the difference doesn't change anything, because matched rows are then
searched in a child table with `EQ` expression which do not match
nulls.
Before:
`oldval` old_is `newval`
Now:
`oldval` is_null or (`newval` is_not_null and `oldval` eq `newval`)
Closes #3645
diff --git a/src/box/sql/fkey.c b/src/box/sql/fkey.c
index 091778fc8..56885e448 100644
--- a/src/box/sql/fkey.c
+++ b/src/box/sql/fkey.c
@@ -787,24 +787,39 @@ fkey_action_trigger(struct Parse *pParse, struct
Table *pTab, struct fkey *fkey,
/*
* For ON UPDATE, construct the next term of the
- * WHEN clause. The final WHEN clause will be like
+ * WHEN clause, which should return false in case
+ * there is a reason to for a broken constrant in
+ * a parent table:
+ * no_action_needed := `oldval` IS NULL OR
+ * (`newval` IS NOT NULL AND
+ * `newval` = `oldval`)
+ *
+ * The final WHEN clause will be like
* this:
*
- * WHEN NOT(old.col1 = new.col1 AND ... AND
- * old.colN = new.colN)
+ * WHEN NOT( no_action_needed(col1) AND ...
+ * no_action_needed(colN))
*/
if (is_update) {
- struct Expr *l, *r;
- l = sqlite3PExpr(pParse, TK_DOT,
- sqlite3ExprAlloc(db, TK_ID, &t_old, 0),
- sqlite3ExprAlloc(db, TK_ID, &t_to_col,
- 0));
- r = sqlite3PExpr(pParse, TK_DOT,
- sqlite3ExprAlloc(db, TK_ID, &t_new, 0),
- sqlite3ExprAlloc(db, TK_ID, &t_to_col,
- 0));
- eq = sqlite3PExpr(pParse, TK_EQ, l, r);
- when = sqlite3ExprAnd(db, when, eq);
+ struct Expr *old_val = sqlite3PExpr(pParse, TK_DOT,
+ sqlite3ExprAlloc(db, TK_ID, &t_old, 0),
+ sqlite3ExprAlloc(db, TK_ID, &t_to_col, 0));
+ struct Expr *new_val = sqlite3PExpr(pParse, TK_DOT,
+ sqlite3ExprAlloc(db, TK_ID, &t_new, 0),
+ sqlite3ExprAlloc(db, TK_ID, &t_to_col, 0));
+ struct Expr *old_is_null = sqlite3PExpr(
+ pParse, TK_ISNULL,
+ sqlite3ExprDup(db, old_val, 0), NULL);
+ eq = sqlite3PExpr(pParse, TK_EQ, old_val,
+ sqlite3ExprDup(db, new_val, 0));
+ struct Expr *new_non_null =
+ sqlite3PExpr(pParse, TK_NOTNULL, new_val, NULL);
+ struct Expr *non_null_eq =
+ sqlite3PExpr(pParse, TK_AND, new_non_null, eq);
+ struct Expr *no_action_needed =
+ sqlite3PExpr(pParse, TK_OR, old_is_null,
+ non_null_eq);
+ when = sqlite3ExprAnd(db, when, no_action_needed);
}
if (action != FKEY_ACTION_RESTRICT &&
diff --git a/test/sql-tap/fkey1.test.lua b/test/sql-tap/fkey1.test.lua
index 3c29b097d..b419e4d59 100755
--- a/test/sql-tap/fkey1.test.lua
+++ b/test/sql-tap/fkey1.test.lua
@@ -1,6 +1,6 @@
#!/usr/bin/env tarantool
test = require("sqltester")
-test:plan(18)
+test:plan(25)
-- This file implements regression tests for foreign keys.
@@ -233,4 +233,27 @@ test:do_execsql_test(
-- </fkey1-6.3>
})
+-- gh-3645: update col=Null do not activates ON UPDATE trigger.
+
+test:do_select_tests(
+ "fkey1-7",
+ {
+ {"0",
+ [[
+ CREATE TABLE T12 (A INTEGER PRIMARY KEY,
+ B CHAR(5) UNIQUE);
+ CREATE TABLE T13 (A INTEGER PRIMARY KEY,
+ B CHAR(5) UNIQUE,
+ FOREIGN KEY (B) REFERENCES T12 (B) ON UPDATE SET NULL);
+ INSERT INTO T12 VALUES (1,'a');
+ INSERT INTO T13 VALUES (1,'a');
+ ]], {}},
+ {"1", "UPDATE T12 SET B = NULL", {}},
+ {"2", "SELECT * FROM T12", {1, ""}},
+ {"3", "SELECT * FROM T13", {1, ""}},
+ {"4", "UPDATE T12 SET B = 'a'", {}},
+ {"5", "SELECT * FROM T12", {1, "a"}},
+ {"6", "SELECT * FROM T13", {1, ""}},
+ })
+
test:finish_test()
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