Connection Pools
Overview
In this guide, you can learn about how PyMongo uses connection pools to manage connections to a MongoDB deployment and how you can configure connection pool settings in your application.
A connection pool is a cache of open database connections maintained by PyMongo. When your application requests a connection to MongoDB, PyMongo seamlessly gets a connection from the pool, performs operations, and returns the connection to the pool for reuse.
Connection pools help reduce application latency and the number of times new connections are created by PyMongo.
Configuring Connection Pools
You can specify the following connection pool settings in your MongoClient object or in
your connection URI:
Setting | Description |
|---|---|
| Sets the time that PyMongo waits when connecting a new
socket before timing out. Defaults to 20000 |
| Sets the maximum number of connections that each pool can establish concurrently.
If this limit is reached, further requests wait until a connection is established
or another in-use connection is checked back into the pool. Defaults to 2 |
| Sets the maximum time that a connection can remain idle in the pool. Defaults to None (no limit) |
| Sets the maximum number of concurrent connections that the pool maintains.
If the maximum pool size is reached, further requests wait until a connection
becomes available. Defaults to 100 |
| Sets the minimum number of concurrent connections that the pool maintains. If
the number of open connections falls below this value due to network errors,
PyMongo attempts to create new connections to maintain this minimum. Defaults to 0 |
| Sets the length of time that PyMongo waits for a response from the server
before timing out. Defaults to None (no timeout) |
| Sets how long a thread waits for a connection to become available in the connection pool
before timing out. Defaults to None (no timeout) |
The following code creates a client with a maximum connection pool size of 50 by using the
maxPoolSize parameter:
client = MongoClient(host, port, maxPoolSize=50)
The following code creates a client with the same configuration as the preceding example, but uses a connection URI:
client = MongoClient("mongodb://<host>:<port>/?maxPoolSize=50")
Additional Information
To learn more about connection pools, see Connection Pool Overview in the MongoDB Server manual.
API Documentation
To learn more about any of the methods or types discussed in this guide, see the following API documentation: