Can't connect to MySQL server.

[kloostermanw]

• TwinDB Backup version: 3.1.1
• Operating System: Ubuntu 22.04
• Mysql: 8.0.30
• Percona-xtrabackup-80: 8.0.30

Description

When I run

twindb-backup --xtrabackup-binary=/usr/bin/xtrabackup --xbstream-binary=/usr/bin/xbstream backup hourly

I get the following error message:

ERROR: mysql_source.get_connection():541: Can't connect to MySQL server on 127.0.0.1
ERROR: mysql_source.get_connection():541: Can't connect to MySQL server on 127.0.0.1

But the backup is running fine.

What I Did

I investigated what was causing the message. So I update the log line in mysql_source on line 543 as following

backup/twindb_backup/source/mysql_source.py

Lines 540 to 544 in ed72278

	except OperationalError as err:
	LOG.error(
	"Can't connect to MySQL server on %s",
	self._connect_info.hostname,
	)

LOG.error(
    "Can't connect to MySQL server on %s",
    str(err),
)

And this give me the following error message.

ERROR: mysql_source.get_connection():541: Can't connect to MySQL server on (1193, "Unknown system variable 'wsrep_on'")

I think for some reason the check in is_galera bubbles up as an error message.

backup/twindb_backup/source/mysql_source.py

Lines 479 to 504 in ed72278

	def is_galera(self):
	"""Check if local MySQL instance is a Galera cluster
	:return: True if it's a Galera.
	:rtype: bool
	"""
	try:
	with self._cursor() as cursor:
	cursor.execute("SELECT @@wsrep_on as wsrep_on")
	row = cursor.fetchone()
	return str(row["wsrep_on"]).lower() == "1" or str(row["wsrep_on"]).lower() == "on"
	except (
	pymysql.InternalError,
	OperationalError,
	MySQLSourceError,
	) as err:
	error_code = err.args[0]
	error_message = err.args[1]
	if error_code == 1193:
	LOG.debug("Galera is not supported or not enabled")
	return False
	else:
	LOG.error(error_message)
	raise