diff --git a/mysql.py b/mysql.py
index 95f9bb1..768f7b4 100644
--- a/mysql.py
+++ b/mysql.py
@@ -349,7 +349,7 @@ def fetch_mysql_status(conn):
 		status[row['Variable_name']] = row['Value']
 
 	# calculate the number of unpurged txns from existing variables
-	if 'Innodb_max_trx_id' in status:
+	if 'Innodb_max_trx_id' in status and 'Innodb_purge_trx_id' in status:
 		status['Innodb_unpurged_txns'] = int(status['Innodb_max_trx_id']) - int(status['Innodb_purge_trx_id'])
 
 	if 'Innodb_lsn_last_checkpoint' in status:
@@ -582,8 +582,8 @@ def read_callback():
 	 collectd.register_config(configure_callback)
 
 if __name__ == "__main__" and not COLLECTD_ENABLED:
-	print "Running in test mode, invoke with"
-	print sys.argv[0] + " Host Port User Password "
+	print("Running in test mode, invoke with")
+	print(sys.argv[0] + " Host Port User Password ")
 	MYSQL_CONFIG['Host'] = sys.argv[1]
 	MYSQL_CONFIG['Port'] = int(sys.argv[2])
 	MYSQL_CONFIG['User'] = sys.argv[3]