Load balancing

Four load balancing strategies are supported to distribute read-only statements over the configured MySQL slave servers:

random

Chooses a random server whenever a statement is executed.

random once (default)

Chooses a random server after the first statement is executed, and uses the decision for the rest of the PHP request.

It is the default, and the lowest impact on the connection state.

round robin

Iterates over the list of configured servers.

user-defined via callback

Is used to implement any other strategy.

The load balancing policy is configured in the plugins configuration file using the random, roundrobin, and user filters.