Elasticsearch contains multiple circuit breakers used to prevent operations from causing an OutOfMemoryError. Each breaker specifies a limit for how much memory it can use. Additionally, there is a parent-level breaker that specifies the total amount of memory that can be used across all breakers.
These settings can be dynamically updated on a live cluster with the cluster-update-settings API.
Parent circuit breakeredit
The parent-level breaker can be configured with the following setting:
- Starting limit for overall parent breaker, defaults to 70% of JVM heap.
Field data circuit breakeredit
The field data circuit breaker allows Elasticsearch to estimate the amount of memory a field will require to be loaded into memory. It can then prevent the field data loading by raising an exception. By default the limit is configured to 60% of the maximum JVM heap. It can be configured with the following parameters:
- Limit for fielddata breaker, defaults to 60% of JVM heap
- A constant that all field data estimations are multiplied with to determine a final estimation. Defaults to 1.03
Request circuit breakeredit
The request circuit breaker allows Elasticsearch to prevent per-request data structures (for example, memory used for calculating aggregations during a request) from exceeding a certain amount of memory.
- Limit for request breaker, defaults to 60% of JVM heap
- A constant that all request estimations are multiplied with to determine a final estimation. Defaults to 1
In flight requests circuit breakeredit
The in flight requests circuit breaker allows Elasticsearch to limit the memory usage of all currently active incoming requests on transport or HTTP level from exceeding a certain amount of memory on a node. The memory usage is based on the content length of the request itself.
- Limit for in flight requests breaker, defaults to 100% of JVM heap. This means that it is bound by the limit configured for the parent circuit breaker.
- A constant that all in flight requests estimations are multiplied with to determine a final estimation. Defaults to 1
Script compilation circuit breakeredit
Slightly different than the previous memory-based circuit breaker, the script compilation circuit breaker limits the number of inline script compilations within a period of time.
See the "prefer-parameters" section of the scripting documentation for more information.
- Limit for the number of unique dynamic scripts within a certain interval that are allowed to be compiled. Defaults to 75/5m, meaning 75 every 5 minutes.