Managed Connection Pooling overview

This page describes what Managed Connection Pooling is and how to use it with your Cloud SQL instances.

Managed Connection Pooling lets you scale your workloads by optimizing resource utilization and connection latency for your Cloud SQL for MySQL instances using pooling. Managed Connection Pooling creates a pool of threads to handle incoming requests. This delivers significant performance improvements, especially for scaled connections, by absorbing sudden connection spikes without overloading the server with a growth in the number of threads.

While you can use Managed Connection Pooling for any transactional workloads, Managed Connection Pooling provides the most throughput and latency benefit with applications that contain short-lived connections, or applications that result in a connection surge.

For long-lived connections, the connection performance using Managed Connection Pooling can be slightly lower than when using a direct connection. In this case, Managed Connection Pooling provides connection scaling when the number of connections is very high. However, for applications that typically establish long-lived connections, you might use direct connections to your instance instead.

For more information on how to enable Managed Connection Pooling, see Configure Managed Connection Pooling.

Requirements

To use Managed Connection Pooling, your instance must meet the following requirements:

  • Your instance must be a Cloud SQL Enterprise Plus edition instance.
  • Managed Connection Pooling requires a minimum maintenance version number of MYSQL_$version.R20250304.00_01. For more information, see Self-service maintenance.

Available configuration options

You can customize Managed Connection Pooling by using the following configuration parameters:

  • max_pool_size: the amount of concurrency for MCP. The default value is number of cores in your database.

Limitations

Consider the following limitations when using Managed Connection Pooling with your Cloud SQL Enterprise Plus edition instances:

  • Enabling Managed Connection Pooling on an existing instance results in a database restart.
  • When you use the Cloud SQL API to enable, disable, or configure Managed Connection Pooling, the instance.update API can't contain any other instance configuration updates.

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