FOSElasticaBundle/Resources/doc/cookbook/logging.md

Logging and its performance considerations

By default, FOSElasticaBundle sets a logger against each Elastica client configured and logs all information sent to and received from Elasticsearch. This can lead to large memory usage during population or reindexing of an index.

By default FOSElasticaBundle will only enable a logger when debug mode is enabled, meaning in a production environment there wont be a logger enabled. To enable a logger anyway, you can set the logger property of a client configuration to true or a service id of a logging service you wish to use.

# app/config/config.yml
fos_elastica:
    clients:
        default:
            host: example.com
            logger: true

Custom Logger Service

It is also possible to specify a custom logger instance to be injected into each client by specifying the service id of the logger you wish to use.

# app/config/config.yml
fos_elastica:
    clients:
        default:
            host: example.com
            logger: 'acme.custom.logger'