The indices module controls index-related settings that are globally managed for all indices, rather than being configurable at a per-index level.

Available settings include:

Circuit breaker
Circuit breakers set limits on memory usage to avoid out of memory exceptions.
Fielddata cache
Set limits on the amount of heap used by the in-memory fielddata cache.
Node query cache
Configure the amount heap used to cache queries results.
Indexing buffer
Control the size of the buffer allocated to the indexing process.
Shard request cache
Control the behaviour of the shard-level request cache.
Control the resource limits on the shard recovery process.