def get_history(self, timeline):
history_path = 'pg_{0}/{1:08X}.history'.format(self.wal_name, timeline)
try:
cursor = self._connection.cursor()
cursor.execute('SELECT isdir, modification FROM pg_catalog.pg_stat_file(%s)', (history_path,))
isdir, modification = cursor.fetchone()
if not isdir:
cursor.execute('SELECT pg_catalog.pg_read_file(%s)', (history_path,))
history = list(parse_history(cursor.fetchone()[0]))
if history[-1][0] == timeline - 1:
history[-1].append(modification.isoformat())
return history
except Exception:
logger.exception('Failed to read and parse %s', (history_path,))
def get_history(self, timeline):
history_path = os.path.join(self.wal_dir, '{0:08X}.history'.format(timeline))
history_mtime = mtime(history_path)
if history_mtime:
try:
with open(history_path, 'r') as f:
history = f.read()
history = list(parse_history(history))
if history[-1][0] == timeline - 1:
history_mtime = datetime.fromtimestamp(history_mtime).replace(tzinfo=tz.tzlocal())
history[-1].append(history_mtime.isoformat())
return history
except Exception:
logger.exception('Failed to read and parse %s', (history_path,))
def _check_timeline_and_lsn(self, leader):
local_timeline, local_lsn = self._get_local_timeline_lsn()
if local_timeline is None or local_lsn is None:
return
if isinstance(leader, Leader):
if leader.member.data.get('role') != 'master':
return
# standby cluster
elif not self.check_leader_is_not_in_recovery(
**leader.conn_kwargs(self._postgresql.config.replication)):
return
history = need_rewind = None
try:
with self._postgresql.get_replication_connection_cursor(
**leader.conn_kwargs()) as cur:
cur.execute('IDENTIFY_SYSTEM')
master_timeline = cur.fetchone()[1]
logger.info('master_timeline=%s', master_timeline)
if local_timeline > master_timeline: # Not always supported by pg_rewind
need_rewind = True
elif master_timeline > 1:
cur.execute('TIMELINE_HISTORY %s', (master_timeline, ))
history = bytes(cur.fetchone()[1]).decode('utf-8')
logger.info('master: history=%s', history)
else: # local_timeline == master_timeline == 1
need_rewind = False
except Exception:
return logger.exception(
'Exception when working with master via replication connection'
)
if history is not None:
for parent_timeline, switchpoint, _ in parse_history(history):
if parent_timeline == local_timeline:
try:
need_rewind = parse_lsn(local_lsn) >= switchpoint
except (IndexError, ValueError):
logger.exception('Exception when parsing lsn')
break
elif parent_timeline > local_timeline:
break
self._state = need_rewind and REWIND_STATUS.NEED or REWIND_STATUS.NOT_NEED
