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Connection Pooling in Appsmith

Connection pooling is particularly important when developing applications that require frequent interactions with a database. Keeping unnecessary connections open can be resource-intensive and may lead to performance degradation, which is why connection pooling plays a crucial role.

How connection pooling works in Appsmith

Here’s a step-by-step explanation of how Appsmith manages connection pooling:

  1. Initialization: When an Appsmith application starts, it initializes the pool by creating a number of database connections up to a configured minimum.

  2. Connection Request: When a database query is triggered from a widget or an API call, Appsmith first checks the pool for an available connection.

  3. Connection Allocation: If an idle connection is available in the pool, it allocates that connection to the current request.

  4. Connection Release: Once the query execution is complete, instead of closing the database connection, Appsmith releases it back to the connection pool, marking it as available for future use.

  5. Connection Creation: If no idle connections are available and the pool has not reached its maximum size, Appsmith may create a new connection and add it to the pool.

  6. Connection Limiting: Pooling ensures that the number of open connections does not exceed a certain limit, as defined by the maximum configuration of the pool.

  7. Connection Closing: Connections that are idle for an extended period or have become invalid due to network issues or database restarts are closed and removed from the pool.

Benefits of connection pooling in Appsmith

  • Improved Performance: Connection pools reduce the overhead associated with establishing and closing connections, leading to faster response times.

  • Resource Optimization: It ensures efficient use of database connections which helps in minimizing the resource usage on both the application and database server.

  • Scalability: With connection pooling, Appsmith applications can handle increased load by reusing connections, thereby supporting more concurrent users.

  • Resilience: Connection pools often have mechanisms to automatically handle failed connections, thus improving the robustness of the application.

Configuration of connection pooling

By default, Appsmith provides a pool limit of 5 that works well for standard use cases. However, developers can tweak these parameters in the Admin Settings of their instance.

Connection pooling is a fundamental aspect of Appsmith's backend infrastructure, critical for developers building scalable and efficient applications. It ensures that database operations are handled gracefully, providing a better user experience and making the best use of available resources.