class RecoveryManagement(object):
def __init__(self, log_path, path='recovery.txt'):
self.path = path
self.db = Datasource()
self.log_parser = LogParser(log_path)
self.log_writer = LogWriter(log_path)
self.generator = SearchEngineGenerator()
def __call__(self, recover_line):
with open(self.path, "a") as f:
save_redo_list = []
n_line, undo_list = self.log_parser.find_checkpoint()
for log in self.log_parser.forward(n_line=n_line):
groups = log.groups()
command_type = groups[0]
if 'recover' in command_type:
break
else:
if len(groups) == 2:
if 'start' in groups[1]:
undo_list.append(command_type)
elif 'commit' in groups[1]:
undo_list.remove(command_type)
# transaction = self.log_parser.find_transaction(command_type)
# for t in transaction:
# self.execute_recovery(command_type, t, 'new', 'redo')
save_redo_list.append(command_type)
elif 'abort' in groups[1]:
undo_list.remove(command_type)
# transaction = self.log_parser.find_transaction(command_type)
# for t in transaction:
# self.execute_recovery(command_type, t, 'old', 'redo')
save_redo_list.append(command_type)
elif command_type.startswith('<T'):
self.execute_recovery(command_type, groups[1:], 'new',
'redo')
save_undo_list = undo_list.copy()
for log in self.log_parser.backward():
groups = log.groups()
command_type = groups[0]
if command_type in undo_list and 'start' in groups[1]:
undo_list.remove(command_type)
# transaction = self.log_parser.find_transaction(command_type)
# for t in reversed(transaction):
# self.execute_recovery(command_type, t, 'old', 'undo')
self.log_writer.free_write(f"{command_type} abort")
elif command_type in undo_list and command_type.startswith(
'<T'):
self.execute_recovery(command_type, groups[1:], 'old',
'undo')
self.log_writer.recover(recover_line)
self.log_writer.checkpoint()
f.write(f"recover {recover_line + 1}\n")
f.write(f"redo {', '.join(save_redo_list)}\n")
f.write(f"undo {', '.join(save_undo_list)}\n")
def execute_recovery(self, t_id, t, value_type, do_type):
'''
t (tuple): 트랜잭션 튜플
value_type (enum): old value인지 new value인지
['old', 'new']
do_Type (enum): undo or redo
['undo', 'redo']
'''
assert value_type in ['old', 'new'], "Value 타입이 잘못되었습니다."
assert do_type in ['undo', 'redo'], "Do 타입이 잘못되었습니다."
is_undo = True if do_type == 'undo' else False
# Update
if len(t) == 6:
table, key_field, key, target_field, old_value, new_value = t
# value = new_value if value_type in 'new' else old_value
value = new_value if do_type == 'redo' else old_value
if is_undo:
self.log_writer.free_write(
f"{t_id}, <{table}>.<id:{key}>.<{target_field}>, <{new_value}>, <{old_value}>"
)
else:
self.log_writer.free_write(f"#redo {t_id}_{t}")
self.db.update_table(table, key_field, key, target_field, value)
# Delete
elif len(t) == 5:
table, key_field, key, old_tuple, _ = t
if isinstance(old_tuple, str):
if old_tuple != 'None':
old_tuple = old_tuple[1:-1]
if old_tuple.endswith(","):
old_tuple = old_tuple[:-1]
if value_type == 'new':
if is_undo:
self.log_writer.free_write(
f"{t_id}, <{table}>.<{key_field}:{key}>, <{old_tuple}>, <None>"
)
else:
self.log_writer.free_write(f"#redo {t_id}_{t}")
self.db.delete_table(table, key_field, key)
else:
if old_tuple != 'None':
if is_undo:
self.log_writer.free_write(
f"{t_id}, <{table}>.<{key_field}:{key}>, <None>, <{old_tuple}>"
)
else:
self.log_writer.free_write(f"#redo {t_id}_{t}")
self.db.insert_table(table, old_tuple)