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MySQL max_connections

Calculate the total number of simultaneous connections available to all users combined on your Aiven for MySQL® service, and learn why the per-user connection limit is a separate setting.

The maximum number of simultaneous connections in Aiven for MySQL® depends on how much RAM your service has. This max_connections value applies to all users of the service combined, not to each user individually.

note

Independent of the size, an extra_connection with a value of 1 is added for the system process.

Under 4 GiB​

For services with less than 4 GiB of RAM, the number of allowed connections is per GiB:

max_connections=75×RAM+extra_connection{max\_connections} = 75 \times RAM + extra\_connection
Example

With 2 GiB of RAM, the maximum number of connections is max_connections=75×2+1{max\_connections} = 75 \times 2 + 1

4 GiB or more​

For services with 4 GiB or more of RAM, the number of allowed connections is per GiB:

max_connections=100×RAM+extra_connection{max\_connections} = 100 \times RAM + extra\_connection
Example

With 7 GiB of RAM, the maximum number of connections is max_connections=100×7+1{max\_connections} = 100 \times 7 + 1

Increase the maximum number of connections​

max_connections isn't a configurable advanced parameter in Aiven for MySQL. Its value is always calculated from your service's plan and RAM using the formulas described earlier. To raise the total number of simultaneous connections available to your service, upgrade to a plan with more RAM.

Per-user connection limits​

MySQL supports a separate, per-user limit called max_user_connections, which caps how many simultaneous connections a single database user can open. If a client reports an error such as User 'exampleuser' has exceeded the 'max_user_connections' resource, that user has hit this per-user limit, not the service-wide max_connections limit.

Aiven for MySQL doesn't expose max_user_connections as a configurable option, and raising your service's max_connections value doesn't change any per-user limit. If your application needs more concurrent connections for a specific database user, distribute connections across multiple database users or reduce the number of concurrent connections that user opens. For help with a persistent per-user connection limit, contact Aiven support.

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