What is connection pooling and why is it needed in web applications?

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A connection to a relational database is a heavy resource that takes time to establish a network connection, authenticate, and allocate memory on the DBMS server. If a web application opens a new connection for every incoming HTTP request, the server will quickly exhaust its resources and slow down.

Connection pooling solves this problem by creating and maintaining a pre-determined number of open connections in a special buffer. When an application needs to execute a query against the database, it takes a ready connection from the pool, performs the work, and returns it back instead of closing it.

This dramatically reduces response latency for the user and protects the database from overloading due to unexpected traffic spikes. Modern web frameworks and database drivers have built-in pooling mechanisms that can be flexibly configured for specific loads.

When configuring the connection pool, it is important to consider parameters that affect system stability:

1. The maximum pool size should not exceed the database server's capacity for simultaneous connections.
2. The minimum pool size allows keeping ready connections to handle the baseline load.
3. The connection timeout helps prevent infinite thread blocking when the pool is exhausted.
4. Periodic connection health checks prevent errors due to broken network sockets.

What is connection pooling and why is it needed in web applications?

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