[Tarantool-patches] [PATCH 2/2] sql: support constraint drop
Roman Khabibov
roman.habibov at tarantool.org
Sat Feb 1 20:36:33 MSK 2020
Hi! Thanks for the review.
> On Jan 28, 2020, at 20:39, Nikita Pettik <korablev at tarantool.org> wrote:
>
> On 24 Jan 17:21, Roman Khabibov wrote:
>> Hi! Thanks for the review.
>>
>>> On Jan 13, 2020, at 20:00, Nikita Pettik <korablev at tarantool.org> wrote:
>>>
>>> On 09 Jan 13:15, Roman Khabibov wrote:
>>>> diff --git a/src/box/errcode.h b/src/box/errcode.h
>>>> index 3065b1948..9ba42dfb4 100644
>>>> --- a/src/box/errcode.h
>>>> +++ b/src/box/errcode.h
>>>> @@ -221,7 +221,7 @@ struct errcode_record {
>>>> /*166 */_(ER_NO_SUCH_COLLATION, "Collation '%s' does not exist") \
>>>> /*167 */_(ER_CREATE_FK_CONSTRAINT, "Failed to create foreign key constraint '%s': %s") \
>>>> /*168 */_(ER_DROP_FK_CONSTRAINT, "Failed to drop foreign key constraint '%s': %s") \
>>>> - /*169 */_(ER_NO_SUCH_CONSTRAINT, "Constraint %s does not exist") \
>>>> + /*169 */_(ER_NO_SUCH_CONSTRAINT, "Constraint '%s' does not exist in space '%s'") \
>>>
>>> Why did you change error (in scope of this patch)?
>> In the previous patch about constraint_id, I did about the same with ER_CONSTRAINT_EXISTS.
>> Now I decided that changing the error also applies to this patch and it is too small to be
>> a separate patch.
>
> Separation into patches shouldn't be done based on size estimation,
> but rather depending on logical consistency. Please, move to a separate
> patch and add justification for that.
Done.
>>>> diff --git a/src/box/sql/build.c b/src/box/sql/build.c
>>>> index bc50ecbfa..7c4b5760e 100644
>>>> --- a/src/box/sql/build.c
>>>> +++ b/src/box/sql/build.c
>>>> @@ -1469,6 +1469,29 @@ vdbe_emit_stat_space_clear(struct Parse *parse, const char *stat_table_name,
>>>> sql_table_delete_from(parse, src_list, where);
>>>> @@ -1488,17 +1511,6 @@ vdbe_emit_fk_constraint_drop(struct Parse *parse_context, char *constraint_name,
>>>> sqlVdbeAddOp4(vdbe, OP_String8, 0, key_reg, 0, constraint_name,
>>>> P4_DYNAMIC);
>>>> sqlVdbeAddOp2(vdbe, OP_Integer, child_id, key_reg + 1);
>>>> - const char *error_msg =
>>>> - tt_sprintf(tnt_errcode_desc(ER_NO_SUCH_CONSTRAINT),
>>>> - constraint_name);
>>>> - if (vdbe_emit_halt_with_presence_test(parse_context,
>>>> - BOX_FK_CONSTRAINT_ID, 0,
>>>> - key_reg, 2, ER_NO_SUCH_CONSTRAINT,
>>>> - error_msg, false,
>>>> - OP_Found) != 0) {
>>>> - sqlDbFree(parse_context->db, constraint_name);
>>>> - return;
>>>> - }
>>>
>>> Why did you drop this check?
>>>
>>>> sqlVdbeAddOp3(vdbe, OP_MakeRecord, key_reg, 2, key_reg + 2);
>>>> sqlVdbeAddOp2(vdbe, OP_SDelete, BOX_FK_CONSTRAINT_ID, key_reg + 2);
>>>> VdbeComment((vdbe, "Delete FK constraint %s", constraint_name));
>>>> @@ -1523,12 +1535,6 @@ vdbe_emit_ck_constraint_drop(struct Parse *parser, const char *ck_name,
>>>> sqlVdbeAddOp2(v, OP_Integer, space_id, key_reg);
>>>> sqlVdbeAddOp4(v, OP_String8, 0, key_reg + 1, 0,
>>>> sqlDbStrDup(db, ck_name), P4_DYNAMIC);
>>>> - const char *error_msg =
>>>> - tt_sprintf(tnt_errcode_desc(ER_NO_SUCH_CONSTRAINT), ck_name);
>>>> - if (vdbe_emit_halt_with_presence_test(parser, BOX_CK_CONSTRAINT_ID, 0,
>>>> - key_reg, 2, ER_NO_SUCH_CONSTRAINT,
>>>> - error_msg, false, OP_Found) != 0)
>>>> - return;
>>>
>>> Same question.
>> I dropped these checks, because I thought that the data are consistent. These two
>> functions are called when:
>> 1) DROP TABLE. If the constraint exist in struct space, then the corresponding tuple
>> exists in _ck/_fk system space too. Therefore this error can not occur in box.
>>
>> 2) ALTER TABLE DROP CONSTRAINT. Analogically, I check the constraint for existence in
>> sql_drop_constraint() and throw error on parsing level.
>
> Data can be consistent at the parsing stage, but be inconsistent during
> execution. Especially taking into account 'prepare' mechanism having
> been recently introduced. So please put these checks back.
Done.
>>>> @@ -2050,28 +2044,61 @@ fk_constraint_change_defer_mode(struct Parse *parse_context, bool is_deferred)
>>>> is_deferred;
>>>> }
>>>>
>>>> +/**
>>>> + * Emit code to drop the entry from _index or _ck_contstraint or
>>>> + * _fk_constraint space corresponding with the constraint type.
>>>> + */
>>>> void
>>>> -sql_drop_foreign_key(struct Parse *parse_context)
>>>> +sql_drop_constraint(struct Parse *parse_context)
>>>> {
>>>> - vdbe_emit_fk_constraint_drop(parse_context, constraint_name,
>>>> - child->def->id);
>>>> + uint32_t space_id = space->def->id;
>>>> + assert(id->type == CONSTRAINT_TYPE_PK || id->type ==
>>>> + CONSTRAINT_TYPE_UNIQUE || id->type == CONSTRAINT_TYPE_FK ||
>>>> + id->type == CONSTRAINT_TYPE_CK);
>>>
>>> Instead of such huge checks iterating over all possible variants,
>>> enum can be extended with _MAX last element (see enum index_type for
>>> example) and check becomes quite simple: assert(id->type < contraint_type_MAX);
>> Ok, but I thought that this assert is needed to prevent the following situation.
>> For example, I have added new value to enum constraint_type, and I forgot to
>> extend this switch-case construction. Then I will get unreachable().
>
> Yep, and what's wrong with this assumption?
>
>>>> + vdbe_emit_ck_constraint_drop(parse_context, name, space_id);
>>>> + break;
>>>> + default:
>>>> + unreachable();
>>>> + }
>>>> /*
>>>> * We account changes to row count only if drop of
>>>> * foreign keys take place in a separate
>> +/**
>> + * Emit code to drop the entry from _index or _ck_contstraint or
>> + * _fk_constraint space corresponding with the constraint type.
>> + */
>> void
>> -sql_drop_foreign_key(struct Parse *parse_context)
>> +sql_drop_constraint(struct Parse *parse)
>> {
>
> Did I request this renaming?
No, but it slightly reduced the code.
>> - struct drop_entity_def *drop_def = &parse_context->drop_fk_def.base;
>> - assert(drop_def->base.entity_type == ENTITY_TYPE_FK);
>> + struct drop_entity_def *drop_def = &parse->drop_constraint_def.base;
>> + assert(drop_def->base.entity_type == ENTITY_TYPE_CONSTRAINT);
>> assert(drop_def->base.alter_action == ALTER_ACTION_DROP);
>> const char *table_name = drop_def->base.entity_name->a[0].zName;
>> assert(table_name != NULL);
>> - struct space *child = space_by_name(table_name);
>> - if (child == NULL) {
>> + struct space *space = space_by_name(table_name);
>> + if (space == NULL) {
>> diag_set(ClientError, ER_NO_SUCH_SPACE, table_name);
>> - parse_context->is_aborted = true;
>> + parse->is_aborted = true;
>> return;
>> }
>> - char *constraint_name =
>> - sql_name_from_token(parse_context->db, &drop_def->name);
>> - if (constraint_name == NULL) {
>> - parse_context->is_aborted = true;
>> + char *name = sql_name_from_token(parse->db, &drop_def->name);
>> + if (name == NULL) {
>> + parse->is_aborted = true;
>> return;
>> }
>> - vdbe_emit_fk_constraint_drop(parse_context, constraint_name,
>> - child->def->id);
>> + struct constraint_id *id = space_find_constraint_id(space, name);
>> + if (id == NULL) {
>> + diag_set(ClientError, ER_NO_SUCH_CONSTRAINT, name, table_name);
>> + parse->is_aborted = true;
>> + return;
>> + }
>> + uint32_t space_id = space->def->id;
>> + assert(id->type < constraint_type_MAX);
>> + switch (id->type) {
>> + case CONSTRAINT_TYPE_PK:
>> + case CONSTRAINT_TYPE_UNIQUE: {
>> + uint32_t index_id = box_index_id_by_name(space_id, name,
>> + strlen(name));
>> + /*
>> + * We have already sure, that this index exists,
>> + * so we don't check index_id for BOX_ID_NIL.
>> + */
>
> Nit: have already assured/verified (sure is an adjective/adverb).
Done.
>> + assert(index_id != BOX_ID_NIL);
>> + int space_id_reg = ++parse->nMem;
>> + int index_id_reg = ++parse->nMem;
>> + struct Vdbe *v = sqlGetVdbe(parse);
>> + assert(v != NULL);
>> + sqlVdbeAddOp2(v, OP_Integer, space_id, space_id_reg);
>> + vdbe_emit_index_drop(parse, index_id, index_id_reg,
>> + space_id_reg);
>> + break;
>> + }
commit 818af1cca284eb6c19b7367f20c00de26b8d2305
Author: Roman Khabibov <roman.habibov at tarantool.org>
Date: Thu Jan 2 20:13:36 2020 +0300
sql: support constraint drop
Extend <ALTER TABLE> statement to drop table constraints by their
names.
Closes #4120
@TarantoolBot document
Title: Drop table constraints in SQL
Now, it is possible to drop table constraints (PRIMARY KEY,
UNIQUE, FOREIGN KEY, CHECK) using
<ALTER TABLE table_name DROP CONSTRAINT constraint_name> statement
by their names.
For example:
tarantool> box.execute([[CREATE TABLE test (
a INTEGER PRIMARY KEY,
b INTEGER,
CONSTRAINT cnstr CHECK (a >= 0)
);]])
---
- row_count: 1
...
tarantool> box.execute('ALTER TABLE test DROP CONSTRAINT cnstr;')
---
- row_count: 1
...
The same for all the other constraints.
diff --git a/src/box/constraint_id.h b/src/box/constraint_id.h
index 21f067cdc..ed4f37426 100755
--- a/src/box/constraint_id.h
+++ b/src/box/constraint_id.h
@@ -40,6 +40,7 @@ enum constraint_type {
CONSTRAINT_TYPE_UNIQUE,
CONSTRAINT_TYPE_FK,
CONSTRAINT_TYPE_CK,
+ constraint_type_MAX,
};
extern const char *constraint_type_strs[];
diff --git a/src/box/sql/build.c b/src/box/sql/build.c
index d9bf8de91..27963c455 100644
--- a/src/box/sql/build.c
+++ b/src/box/sql/build.c
@@ -2052,35 +2052,74 @@ fk_constraint_change_defer_mode(struct Parse *parse_context, bool is_deferred)
is_deferred;
}
+/**
+ * Emit code to drop the entry from _index or _ck_contstraint or
+ * _fk_constraint space corresponding with the constraint type.
+ */
void
-sql_drop_foreign_key(struct Parse *parse_context)
+sql_drop_constraint(struct Parse *parse_context)
{
- struct drop_entity_def *drop_def = &parse_context->drop_fk_def.base;
- assert(drop_def->base.entity_type == ENTITY_TYPE_FK);
+ struct drop_entity_def *drop_def =
+ &parse_context->drop_constraint_def.base;
+ assert(drop_def->base.entity_type == ENTITY_TYPE_CONSTRAINT);
assert(drop_def->base.alter_action == ALTER_ACTION_DROP);
const char *table_name = drop_def->base.entity_name->a[0].zName;
assert(table_name != NULL);
- struct space *child = space_by_name(table_name);
- if (child == NULL) {
+ struct space *space = space_by_name(table_name);
+ if (space == NULL) {
diag_set(ClientError, ER_NO_SUCH_SPACE, table_name);
parse_context->is_aborted = true;
return;
}
- char *constraint_name =
- sql_name_from_token(parse_context->db, &drop_def->name);
- if (constraint_name == NULL) {
+ char *name = sql_name_from_token(parse_context->db, &drop_def->name);
+ if (name == NULL) {
+ parse_context->is_aborted = true;
+ return;
+ }
+ struct constraint_id *id = space_find_constraint_id(space, name);
+ if (id == NULL) {
+ diag_set(ClientError, ER_NO_SUCH_CONSTRAINT, name, table_name);
parse_context->is_aborted = true;
return;
}
- vdbe_emit_fk_constraint_drop(parse_context, constraint_name,
- child->def);
+ struct Vdbe *v = sqlGetVdbe(parse_context);
+ assert(v != NULL);
+ assert(id->type < constraint_type_MAX);
+ switch (id->type) {
+ case CONSTRAINT_TYPE_PK:
+ case CONSTRAINT_TYPE_UNIQUE: {
+ uint32_t index_id = box_index_id_by_name(space->def->id, name,
+ strlen(name));
+ /*
+ * We have already verified, that this index
+ * exists, so we don't check index_id for
+ * BOX_ID_NIL.
+ */
+ assert(index_id != BOX_ID_NIL);
+ int record_reg = ++parse_context->nMem;
+ int space_id_reg = ++parse_context->nMem;
+ int index_id_reg = ++parse_context->nMem;
+ sqlVdbeAddOp2(v, OP_Integer, space->def->id, space_id_reg);
+ sqlVdbeAddOp2(v, OP_Integer, index_id, index_id_reg);
+ sqlVdbeAddOp3(v, OP_MakeRecord, space_id_reg, 2, record_reg);
+ sqlVdbeAddOp2(v, OP_SDelete, BOX_INDEX_ID, record_reg);
+ break;
+ }
+ case CONSTRAINT_TYPE_FK:
+ vdbe_emit_fk_constraint_drop(parse_context, name, space->def);
+ break;
+ case CONSTRAINT_TYPE_CK:
+ vdbe_emit_ck_constraint_drop(parse_context, name, space->def);
+ break;
+ default:
+ unreachable();
+ }
/*
* We account changes to row count only if drop of
- * foreign keys take place in a separate
- * ALTER TABLE DROP CONSTRAINT statement, since whole
- * DROP TABLE always returns 1 (one) as a row count.
+ * constraints take place in a separate ALTER TABLE DROP
+ * CONSTRAINT statement, since whole DROP TABLE always
+ * returns 1 (one) as a row count.
*/
- struct Vdbe *v = sqlGetVdbe(parse_context);
sqlVdbeCountChanges(v);
sqlVdbeChangeP5(v, OPFLAG_NCHANGE);
}
diff --git a/src/box/sql/parse.y b/src/box/sql/parse.y
index cfe1c0012..1a0e89703 100644
--- a/src/box/sql/parse.y
+++ b/src/box/sql/parse.y
@@ -1763,9 +1763,9 @@ cmd ::= alter_table_start(A) RENAME TO nm(N). {
}
cmd ::= ALTER TABLE fullname(X) DROP CONSTRAINT nm(Z). {
- drop_fk_def_init(&pParse->drop_fk_def, X, &Z, false);
+ drop_constraint_def_init(&pParse->drop_constraint_def, X, &Z, false);
pParse->initiateTTrans = true;
- sql_drop_foreign_key(pParse);
+ sql_drop_constraint(pParse);
}
cmd ::= alter_table_start(A) enable(E) CHECK CONSTRAINT nm(Z). {
diff --git a/src/box/sql/parse_def.h b/src/box/sql/parse_def.h
index 2f433e4c0..e6d45b256 100644
--- a/src/box/sql/parse_def.h
+++ b/src/box/sql/parse_def.h
@@ -159,10 +159,6 @@ enum entity_type {
ENTITY_TYPE_TRIGGER,
ENTITY_TYPE_CK,
ENTITY_TYPE_FK,
- /**
- * For assertion checks that constraint definition is
- * created before initialization of a term constraint.
- */
ENTITY_TYPE_CONSTRAINT,
};
@@ -265,7 +261,7 @@ struct drop_trigger_def {
struct drop_entity_def base;
};
-struct drop_fk_def {
+struct drop_constraint_def {
struct drop_entity_def base;
};
@@ -408,11 +404,12 @@ drop_trigger_def_init(struct drop_trigger_def *drop_trigger_def,
}
static inline void
-drop_fk_def_init(struct drop_fk_def *drop_fk_def, struct SrcList *parent_name,
- struct Token *name, bool if_exist)
+drop_constraint_def_init(struct drop_constraint_def *drop_constraint_def,
+ struct SrcList *parent_name, struct Token *name,
+ bool if_exist)
{
- drop_entity_def_init(&drop_fk_def->base, parent_name, name, if_exist,
- ENTITY_TYPE_FK);
+ drop_entity_def_init(&drop_constraint_def->base, parent_name, name,
+ if_exist, ENTITY_TYPE_CONSTRAINT);
}
static inline void
diff --git a/src/box/sql/sqlInt.h b/src/box/sql/sqlInt.h
index d1fcf4761..2ea653c7d 100644
--- a/src/box/sql/sqlInt.h
+++ b/src/box/sql/sqlInt.h
@@ -2237,7 +2237,7 @@ struct Parse {
struct create_trigger_def create_trigger_def;
struct create_view_def create_view_def;
struct rename_entity_def rename_entity_def;
- struct drop_fk_def drop_fk_def;
+ struct drop_constraint_def drop_constraint_def;
struct drop_index_def drop_index_def;
struct drop_table_def drop_table_def;
struct drop_trigger_def drop_trigger_def;
@@ -3747,7 +3747,7 @@ sql_create_foreign_key(struct Parse *parse_context);
* @param parse_context Parsing context.
*/
void
-sql_drop_foreign_key(struct Parse *parse_context);
+sql_drop_constraint(struct Parse *parse_context);
/**
* Now our SQL implementation can't operate on spaces which
diff --git a/test/sql/constraint.result b/test/sql/constraint.result
index 1585c2327..2847fe8ef 100644
--- a/test/sql/constraint.result
+++ b/test/sql/constraint.result
@@ -291,6 +291,67 @@ box.execute('CREATE UNIQUE INDEX d ON t2(i);')
| - Index 'D' already exists in space 'T2'
| ...
+--
+-- gh-4120: Ensure that <ALTER TABLE DROP CONSTRAINT> works
+-- correctly for each type of constraint.
+--
+-- Drop UNIQUE constraint.
+box.space.T2.index.E ~= nil
+ | ---
+ | - true
+ | ...
+box.execute('ALTER TABLE t2 DROP CONSTRAINT e;')
+ | ---
+ | - row_count: 1
+ | ...
+box.space.T2.index.E == nil
+ | ---
+ | - true
+ | ...
+-- Drop PRIMARY KEY constraint named "C".
+box.execute('DROP INDEX d ON t2;')
+ | ---
+ | - row_count: 1
+ | ...
+box.space.T2.index.C ~= nil
+ | ---
+ | - true
+ | ...
+box.execute('ALTER TABLE t2 DROP CONSTRAINT c;')
+ | ---
+ | - row_count: 1
+ | ...
+box.space.T2.index.C == nil
+ | ---
+ | - true
+ | ...
+-- Drop CHECK constraint.
+box.execute('ALTER TABLE t2 ADD CONSTRAINT e CHECK(i > 0);')
+ | ---
+ | - row_count: 1
+ | ...
+box.space.T2.ck_constraint.E ~= nil
+ | ---
+ | - true
+ | ...
+box.execute('ALTER TABLE t2 DROP CONSTRAINT e;')
+ | ---
+ | - row_count: 1
+ | ...
+box.space.T2.ck_constraint.E == nil
+ | ---
+ | - true
+ | ...
+-- Drop FOREIGN KEY constraint.
+box.execute('ALTER TABLE t2 ADD CONSTRAINT e FOREIGN KEY(i) REFERENCES t1(i);')
+ | ---
+ | - row_count: 1
+ | ...
+box.execute('ALTER TABLE t2 DROP CONSTRAINT e;')
+ | ---
+ | - row_count: 1
+ | ...
+
--
-- Cleanup.
--
diff --git a/test/sql/constraint.test.lua b/test/sql/constraint.test.lua
index 163f4309c..12f673dac 100755
--- a/test/sql/constraint.test.lua
+++ b/test/sql/constraint.test.lua
@@ -131,6 +131,28 @@ box.execute('CREATE UNIQUE INDEX e ON t2(i);')
-- uniqueness, index names should be unique in a space.
box.execute('CREATE UNIQUE INDEX d ON t2(i);')
+--
+-- gh-4120: Ensure that <ALTER TABLE DROP CONSTRAINT> works
+-- correctly for each type of constraint.
+--
+-- Drop UNIQUE constraint.
+box.space.T2.index.E ~= nil
+box.execute('ALTER TABLE t2 DROP CONSTRAINT e;')
+box.space.T2.index.E == nil
+-- Drop PRIMARY KEY constraint named "C".
+box.execute('DROP INDEX d ON t2;')
+box.space.T2.index.C ~= nil
+box.execute('ALTER TABLE t2 DROP CONSTRAINT c;')
+box.space.T2.index.C == nil
+-- Drop CHECK constraint.
+box.execute('ALTER TABLE t2 ADD CONSTRAINT e CHECK(i > 0);')
+box.space.T2.ck_constraint.E ~= nil
+box.execute('ALTER TABLE t2 DROP CONSTRAINT e;')
+box.space.T2.ck_constraint.E == nil
+-- Drop FOREIGN KEY constraint.
+box.execute('ALTER TABLE t2 ADD CONSTRAINT e FOREIGN KEY(i) REFERENCES t1(i);')
+box.execute('ALTER TABLE t2 DROP CONSTRAINT e;')
+
--
-- Cleanup.
--
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