chore(mysql-cluster): change dump default theads to 1 for avoid use too many mem

Author: EamonZhang

addons/mysql-cluster/8.0/chart/mysql-cluster/templates/cluster/cronjob.yaml

@@ -66,7 +66,7 @@ spec:
                   endpoint=os.getenv('AWS_ENDPOINT_URL')
                   bucket_name=os.getenv('AWS_BUCKET_NAME')
 
-                  util.dump_instance(now_str, {'s3BucketName': bucket_name, 's3EndpointOverride': endpoint, 'threads': 4, 'compatibility': ['strip_restricted_grants', 'strip_definers', 'ignore_missing_pks'] ,'excludeSchemas': ['mysql_innodb_cluster_metadata','sys','information_schema','performance_schema','mondb'],'compatibility':['strip_restricted_grants', 'strip_definers', 'ignore_missing_pks'] })
+                  util.dump_instance(now_str, {'s3BucketName': bucket_name, 's3EndpointOverride': endpoint, 'threads': 1, 'compatibility': ['strip_restricted_grants', 'strip_definers', 'ignore_missing_pks'] ,'excludeSchemas': ['mysql_innodb_cluster_metadata','sys','information_schema','performance_schema','mondb'],'compatibility':['strip_restricted_grants', 'strip_definers', 'ignore_missing_pks'] })
                   " > /tmp/dump_instance.py
 
                   mysqlsh --uri=${MYSQL_ROOT_USER}@${MYSQL_HOST}:${MYSQL_PORT_NUMBER} -p${MYSQL_ROOT_PASSWORD} --py < /tmp/dump_instance.py