Tuning Your Connection Pool Settings
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Problem | Solution |
|---|---|
Slow application-side operation times that are not reflected in
the database server logs or the
real time panel. | Use Set For example: if a member has a latency of 10000 milliseconds,
setting |
A misconfigured firewall closes a socket connection incorrectly
and the driver cannot detect that the connection closed
improperly. | Use Set |
The server logs or real time panel
show that the application spends too much time creating new
connections. | Not enough connections are available at startup.
Allocate connections in the pool by setting
Set minPoolSize to the number of connections you want to be available at startup. The |
The load on the database is low and there's a small number of
active connections at any time. Application performs fewer
operations at any one time than expected. | Increase maxPoolSize, or increase
the number of active threads in your application or the framework
you are using. |
Database CPU usage is higher than expected. The
server logs or real time panel
show more connection attempts than expected. | Decrease the maxPoolSize or
reduce the number of threads in your application. This can reduce
load and response times. |
Warning
Do not use socketTimeoutMS to prevent long-running
server operations. Instead, use maxTimeMS() with
queries so that the server can cancel long-running operations.
Calculate Maximum Number of Connections
Calculate usage to find the number of operations running for each connection.
Consider four application servers connecting to a replica set with three members. In this scenario, each of the four application servers creates a connection pool for each replica set member.
Calculate the maximum number of connections that are opened by
each application server by multiplying maxPoolSize by the
number of members.
Calculate outgoing connections from an application to a three-member replica set:
100 (maxPoolSize default 100) x 3 (replica set members) = 300 (outgoing connections from the application).
Calculate incoming connections from four application servers to a replica set:
100 (maxPoolSize default 100) x 4 (application servers) = 400 (incoming connections to each mongod).