sql: use common registers instead of temp. for constraints data

Prior to this patch, data needed to form tuple to be inserted to
_fk_constraint and _ck_constraint system spaces (to create
corresponding constraints) was stored in the range of temporary
register. After insertion, temporary registers are released. On
the other hand, this data is required for providing clean-up in
case of creation fail (i.e. removing already created constraints
within one CREATE TABLE statement). Hence, instead of using
temporary registers let's use ordinary ones.

Closes #4183

src/box/sql/build.c

@@ -1078,7 +1078,12 @@ vdbe_emit_ck_constraint_create(struct Parse *parser,
 	struct sql *db = parser->db;
 	struct Vdbe *v = sqlGetVdbe(parser);
 	assert(v != NULL);
-	int ck_constraint_reg = sqlGetTempRange(parser, 6);
+	/*
+	 * Occupy registers for 5 fields: each member in
+	 * _ck_constraint space plus one for final msgpack tuple.
+	 */
+	int ck_constraint_reg = parser->nMem + 1;
+	parser->nMem += 6;
 	sqlVdbeAddOp2(v, OP_SCopy, reg_space_id, ck_constraint_reg);
 	sqlVdbeAddOp4(v, OP_String8, 0, ck_constraint_reg + 1, 0,
 		      sqlDbStrDup(db, ck_def->name), P4_DYNAMIC);
@@ -1102,7 +1107,6 @@ vdbe_emit_ck_constraint_create(struct Parse *parser,
 	save_record(parser, BOX_CK_CONSTRAINT_ID, ck_constraint_reg, 2,
 		    v->nOp - 1, true);
 	VdbeComment((v, "Create CK constraint %s", ck_def->name));
-	sqlReleaseTempRange(parser, ck_constraint_reg, 5);
 }
 
 /**
@@ -1121,10 +1125,11 @@ vdbe_emit_fk_constraint_create(struct Parse *parse_context,
 	struct Vdbe *vdbe = sqlGetVdbe(parse_context);
 	assert(vdbe != NULL);
 	/*
-	 * Occupy registers for 8 fields: each member in
-	 * _constraint space plus one for final msgpack tuple.
+	 * Occupy registers for 9 fields: each member in
+	 * _fk_constraint space plus one for final msgpack tuple.
 	 */
-	int constr_tuple_reg = sqlGetTempRange(parse_context, 10);
+	int constr_tuple_reg = parse_context->nMem + 1;
+	parse_context->nMem += 10;
 	char *name_copy = sqlDbStrDup(parse_context->db, fk->name);
 	if (name_copy == NULL)
 		return;
@@ -1211,7 +1216,6 @@ vdbe_emit_fk_constraint_create(struct Parse *parse_context,
 	}
 	save_record(parse_context, BOX_FK_CONSTRAINT_ID, constr_tuple_reg, 2,
 		    vdbe->nOp - 1, true);
-	sqlReleaseTempRange(parse_context, constr_tuple_reg, 10);
 	return;
 error:
 	parse_context->is_aborted = true;

test/sql/clear.result

@@ -195,3 +195,23 @@ box.space._fk_constraint:select()
 ---
 - []
 ...
+--
+-- Make sure that keys for tuples inserted into system spaces were
+-- not stored in temporary cells.
+--
+box.execute("CREATE TABLE t3(id INT PRIMARY KEY, CONSTRAINT ck1 CHECK(id > 0), CONSTRAINT ck1 FOREIGN KEY(id) REFERENCES t3, CONSTRAINT fk1 FOREIGN KEY(id) REFERENCES t3, CONSTRAINT ck1 CHECK(id < 0));")
+---
+- error: Constraint CK1 already exists
+...
+box.space.t1
+---
+- null
+...
+box.space._ck_constraint:select()
+---
+- []
+...
+box.space._fk_constraint:select()
+---
+- []
+...

test/sql/clear.test.lua

@@ -40,3 +40,12 @@ box.space._ck_constraint:select()
 box.execute("CREATE TABLE t2(id INT PRIMARY KEY, CONSTRAINT fk1 FOREIGN KEY(id) REFERENCES t2, CONSTRAINT fk1 FOREIGN KEY(id) REFERENCES t2);")
 box.space.t2
 box.space._fk_constraint:select()
+
+--
+-- Make sure that keys for tuples inserted into system spaces were
+-- not stored in temporary cells.
+--
+box.execute("CREATE TABLE t3(id INT PRIMARY KEY, CONSTRAINT ck1 CHECK(id > 0), CONSTRAINT ck1 FOREIGN KEY(id) REFERENCES t3, CONSTRAINT fk1 FOREIGN KEY(id) REFERENCES t3, CONSTRAINT ck1 CHECK(id < 0));")
+box.space.t1
+box.space._ck_constraint:select()
+box.space._fk_constraint:select()