MDEV-17859: Clean up the FOREIGN KEY handling

dict_create_add_foreigns_to_dictionary(): Do not commit the transaction.
The operation can still fail in dict_load_foreigns(), and we want
to be able to roll back the transaction.

create_table_info_t::create_table(): Never reset m_drop_before_rollback,
and never commit the transaction. We use a single point of rollback
in ha_innobase::create(). Merge the logic from
row_table_add_foreign_constraints().

storage/innobase/dict/dict0crea.cc

@@ -2268,15 +2268,6 @@ dict_create_add_foreigns_to_dictionary(
 		}
 	}
 
-	trx->op_info = "committing foreign key definitions";
-
-	if (trx_is_started(trx)) {
-
-		trx_commit(trx);
-	}
-
-	trx->op_info = "";
-
 	return(DB_SUCCESS);
 }
 

storage/innobase/handler/ha_innodb.cc

@@ -12514,8 +12514,6 @@ int create_table_info_t::create_table(bool create_fk)
 	int		primary_key_no;
 	uint		i;
 	dict_table_t*	innobase_table = NULL;
-	const char*	stmt;
-	size_t		stmt_len;
 
 	DBUG_ENTER("create_table");
 
@@ -12596,9 +12594,7 @@ int create_table_info_t::create_table(bool create_fk)
 			dict_table_close(innobase_table, TRUE, FALSE);
 			my_error(ER_WRONG_NAME_FOR_INDEX, MYF(0),
 				 FTS_DOC_ID_INDEX_NAME);
-			m_drop_before_rollback = false;
-			error = -1;
-			DBUG_RETURN(error);
+			DBUG_RETURN(-1);
 		case FTS_EXIST_DOC_ID_INDEX:
 		case FTS_NOT_EXIST_DOC_ID_INDEX:
 			break;
@@ -12638,15 +12634,28 @@ int create_table_info_t::create_table(bool create_fk)
 		dict_table_get_all_fts_indexes(innobase_table, fts->indexes);
 	}
 
-	stmt = innobase_get_stmt_unsafe(m_thd, &stmt_len);
-
-	if (stmt) {
-		dberr_t	err = row_table_add_foreign_constraints(
-			create_fk ? m_trx : NULL, stmt, stmt_len, m_table_name,
-			m_create_info->options & HA_LEX_CREATE_TMP_TABLE);
+	size_t stmt_len;
+	if (const char* stmt = innobase_get_stmt_unsafe(m_thd, &stmt_len)) {
+		dberr_t err = create_fk
+			? dict_create_foreign_constraints(
+				m_trx, stmt, stmt_len, m_table_name,
+				m_flags2 & DICT_TF2_TEMPORARY)
+			: DB_SUCCESS;
+		if (err == DB_SUCCESS) {
+			/* Check that also referencing constraints are ok */
+			dict_names_t	fk_tables;
+			err = dict_load_foreigns(m_table_name, NULL,
+						 false, true,
+						 DICT_ERR_IGNORE_NONE,
+						 fk_tables);
+			while (err == DB_SUCCESS && !fk_tables.empty()) {
+				dict_load_table(fk_tables.front(), true,
+						DICT_ERR_IGNORE_NONE);
+				fk_tables.pop_front();
+			}
+		}
 
 		switch (err) {
-
 		case DB_PARENT_NO_INDEX:
 			push_warning_printf(
 				m_thd, Sql_condition::WARN_LEVEL_WARN,
@@ -12679,13 +12688,9 @@ int create_table_info_t::create_table(bool create_fk)
 			break;
 		}
 
-		error = convert_error_code_to_mysql(err, m_flags, NULL);
-
-		if (error) {
-			/* row_table_add_foreign_constraints() dropped
-			the table */
-			m_drop_before_rollback = false;
-			DBUG_RETURN(error);
+		if (err != DB_SUCCESS) {
+			DBUG_RETURN(convert_error_code_to_mysql(
+					    err, m_flags, NULL));
 		}
 	}
 

storage/innobase/include/row0mysql.h

@@ -376,35 +376,6 @@ row_create_index_for_mysql(
 					large. */
 	MY_ATTRIBUTE((warn_unused_result));
 /*********************************************************************//**
-Scans a table create SQL string and adds to the data dictionary
-the foreign key constraints declared in the string. This function
-should be called after the indexes for a table have been created.
-Each foreign key constraint must be accompanied with indexes in
-bot participating tables. The indexes are allowed to contain more
-fields than mentioned in the constraint.
-
-@param[in]	trx		transaction (NULL if not adding to dictionary)
-@param[in]	sql_string	table create statement where
-				foreign keys are declared like:
-				FOREIGN KEY (a, b) REFERENCES table2(c, d),
-				table2 can be written also with the database
-				name before it: test.table2; the default
-				database id the database of parameter name
-@param[in]	sql_length	length of sql_string
-@param[in]	name		table full name in normalized form
-@param[in]	reject_fks	whether to fail with DB_CANNOT_ADD_CONSTRAINT
-				if any foreign keys are found
-@return error code or DB_SUCCESS */
-dberr_t
-row_table_add_foreign_constraints(
-	trx_t*			trx,
-	const char*		sql_string,
-	size_t			sql_length,
-	const char*		name,
-	bool			reject_fks)
-	MY_ATTRIBUTE((warn_unused_result));
-
-/*********************************************************************//**
 The master thread in srv0srv.cc calls this regularly to drop tables which
 we must drop in background after queries to them have ended. Such lazy
 dropping of tables is needed in ALTER TABLE on Unix.

storage/innobase/row/row0mysql.cc

@@ -2497,96 +2497,6 @@ row_create_index_for_mysql(
 	return(err);
 }
 
-/*********************************************************************//**
-Scans a table create SQL string and adds to the data dictionary
-the foreign key constraints declared in the string. This function
-should be called after the indexes for a table have been created.
-Each foreign key constraint must be accompanied with indexes in
-bot participating tables. The indexes are allowed to contain more
-fields than mentioned in the constraint.
-
-@param[in]	trx		transaction (NULL if not adding to dictionary)
-@param[in]	sql_string	table create statement where
-				foreign keys are declared like:
-				FOREIGN KEY (a, b) REFERENCES table2(c, d),
-				table2 can be written also with the database
-				name before it: test.table2; the default
-				database id the database of parameter name
-@param[in]	sql_length	length of sql_string
-@param[in]	name		table full name in normalized form
-@param[in]	reject_fks	whether to fail with DB_CANNOT_ADD_CONSTRAINT
-				if any foreign keys are found
-@return error code or DB_SUCCESS */
-dberr_t
-row_table_add_foreign_constraints(
-	trx_t*			trx,
-	const char*		sql_string,
-	size_t			sql_length,
-	const char*		name,
-	bool			reject_fks)
-{
-	dberr_t	err;
-
-	DBUG_ENTER("row_table_add_foreign_constraints");
-
-	ut_ad(mutex_own(&dict_sys->mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_a(sql_string);
-
-	if (trx) {
-		trx->op_info = "adding foreign keys";
-
-		trx_start_if_not_started_xa(trx, true);
-
-		trx_set_dict_operation(trx, TRX_DICT_OP_TABLE);
-
-		err = dict_create_foreign_constraints(
-			trx, sql_string, sql_length, name, reject_fks);
-
-		DBUG_EXECUTE_IF("ib_table_add_foreign_fail",
-				err = DB_DUPLICATE_KEY;);
-
-		DEBUG_SYNC_C("table_add_foreign_constraints");
-	} else {
-		err = DB_SUCCESS;
-	}
-
-	if (err == DB_SUCCESS) {
-		/* Check that also referencing constraints are ok */
-		dict_names_t	fk_tables;
-		err = dict_load_foreigns(name, NULL, false, true,
-					 DICT_ERR_IGNORE_NONE, fk_tables);
-
-		while (err == DB_SUCCESS && !fk_tables.empty()) {
-			dict_load_table(fk_tables.front(), true,
-					DICT_ERR_IGNORE_NONE);
-			fk_tables.pop_front();
-		}
-	}
-
-	if (err != DB_SUCCESS && trx) {
-		/* We have special error handling here */
-
-		trx->error_state = DB_SUCCESS;
-
-		if (trx_is_started(trx)) {
-
-			trx_rollback_to_savepoint(trx, NULL);
-		}
-
-		row_drop_table_for_mysql(name, trx, SQLCOM_DROP_TABLE, true);
-
-		if (trx_is_started(trx)) {
-
-			trx_commit_for_mysql(trx);
-		}
-
-		trx->error_state = DB_SUCCESS;
-	}
-
-	DBUG_RETURN(err);
-}
-
 /*********************************************************************//**
 Drops a table for MySQL as a background operation. MySQL relies on Unix
 in ALTER TABLE to the fact that the table handler does not remove the