This adds the field data circuit breaker, which is used to estimate
the amount of memory required to load field data before loading it. It
then raises a CircuitBreakingException if the limit is exceeded.
It is configured with two parameters:
`indices.fielddata.cache.breaker.limit` - the maximum number of bytes
of field data to be loaded before circuit breaking. Defaults to
`indices.fielddata.cache.size` if set, unbounded otherwise.
`indices.fielddata.cache.breaker.overhead` - a contast for all field
data estimations to be multiplied with before aggregation. Defaults to
1.03.
Both settings can be configured dynamically using the cluster update
settings API.
The description of the timeout parameter was worded misleadingly; it implied that the API would wait until the cluster reached the desired level and then stayed at that level for the timeout. I've tweaked the sentence to remove the risk of confusion.
Lee Hinman
Boaz Leskes
Clinton Gormley
Richard Boulton