In the dashboard I see there are currently 22 open connections to the DB instance, blocking new connections with the error:
remaining connection slots are reserved for non-replication superuser connections.
I’m accessing the DB from web service API running on EC2 instance and always keep the best practise of:
Connection connection = DriverManager.getConnection(URL, USER_NAME, PASSWORD);
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(SQL_Query_String);
Can I do something else in the code?
Should I do something else in the DB management?
Is there a way to periodically close connections?
Amazon has to set the number of connections based on each model’s right to demand a certain amount of memory and connections
MODEL max_connections innodb_buffer_pool_size
--------- --------------- -----------------------
t1.micro 34 326107136 ( 311M)
m1-small 125 1179648000 ( 1125M, 1.097G)
m1-large 623 5882511360 ( 5610M, 5.479G)
m1-xlarge 1263 11922309120 (11370M, 11.103G)
m2-xlarge 1441 13605273600 (12975M, 12.671G)
m2-2xlarge 2900 27367833600 (26100M, 25.488G)
m2-4xlarge 5816 54892953600 (52350M, 51.123G)
But if you want you can change the max connection size to custom value by
From RDS Console > Parameter Groups > Edit Parameters,
You can change the value of the max_connections parameter to a custom value.
For closing the connections periodically you can setup a cron job some thing like this.
and current_query = '<IDLE>'
and query_start < current_timestamp - interval '5 minutes';