Best Practices for Connection Pooling in MySQL
By Tom Nonmacher
Connection pooling in MySQL is a technique used to enhance the performance of executing commands on a database. With the use of technologies like SQL Server 2019, MySQL 8.0, DB2 11.5, Azure SQL, and Azure Synapse, efficiency and scalability can be achieved. This post will outline some best practices for connection pooling in MySQL.
Setting proper connection pool size is crucial. The pool size should be configured according to the application's need. For applications that require high concurrent connections, the pool size should be large. However, for applications that do not require high concurrency, the pool size can be small. In MySQL 8.0, the connection pool size can be set using the following command:
SET GLOBAL max_connections = 100;
-- Here, 100 is the pool size
Consider using connection pool multiplexing when you have a lot of idle connections. Connection pool multiplexing allows a connection to be reused by multiple clients as long as the previous client has completed its operation. This can be particularly useful in cloud environments like Azure SQL and Azure Synapse where resources are shared among multiple tenants.
Keep track of the connection pool's performance. Regular monitoring can help identify any potential issues or bottlenecks. Tools like Performance Monitor in SQL Server 2019 or the Performance Schema in MySQL 8.0 can provide useful insights. For example, in SQL Server 2019, the following query can be used to monitor the connection pool:
SELECT * FROM sys.dm_exec_connections
In DB2 11.5, connection concentration can be used to manage a large number of simultaneous connections. Connection concentration allows the database manager to reuse a database connection for a different client without closing the connection. This is especially beneficial in systems where the number of clients exceeds the number of available connections.
Lastly, always close the connections when they are not in use. This is one of the most common and yet overlooked best practices. Not closing the connections can lead to connection leaks which may consume all available connections in the pool. In MySQL, a connection can be closed using the following command:
mysql_close($connection);
-- Here, $connection is the connection object
By following these best practices, you can ensure that your MySQL connection pooling is optimized for efficiency and scalability. Remember, connection pooling is not a one-size-fits-all solution. It requires careful configuration and monitoring based on your application and system needs.