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.
Except where noted otherwise, these settings can be dynamically updated on a live cluster with the cluster-update-settings API.
For information about circuit breaker errors, see Circuit breaker errors.
Parent circuit breakeredit
The parent-level breaker can be configured with the following settings:
Determines whether the parent breaker should take real
memory usage into account (
true) or only consider the amount that is reserved by child circuit breakers (
false). Defaults to
Starting limit for overall parent breaker. Defaults to 70% of JVM heap if
true, defaults to 95% of the JVM heap.
Field data circuit breakeredit
The field data circuit breaker estimates the heap memory required to load a field into the field data cache. If loading the field would cause the cache to exceed a predefined memory limit, the circuit breaker stops the operation and returns an error.
- (Dynamic) Limit for fielddata breaker. Defaults to 40% of JVM heap.
A constant that all field data estimations are multiplied with to determine a
final estimation. Defaults to
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.
- (Dynamic) 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
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. This circuit breaker also considers that memory is not only needed for representing the raw request but also as a structured object which is reflected by default overhead.
- (Dynamic) 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.
- (Dynamic) A constant that all in flight requests estimations are multiplied with to determine a final estimation. Defaults to 2.
Accounting requests circuit breakeredit
The accounting circuit breaker allows Elasticsearch to limit the memory usage of things held in memory that are not released when a request is completed. This includes things like the Lucene segment memory.
- (Dynamic) Limit for accounting breaker, defaults to 100% of JVM heap. This means that it is bound by the limit configured for the parent circuit breaker.
- (Dynamic) A constant that all accounting 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
150/5m, meaning 150 every 5 minutes.
If the cluster regularly hits the given
max_compilation_rate, it’s possible the
script cache is undersized, use Nodes Stats to inspect
the number of recent cache evictions,
script.compilations_history. If there are a large
number of recent cache evictions or compilations, the script cache may be
undersized, consider doubling the size of the script cache via the setting
Regex circuit breakeredit
Poorly written regular expressions can degrade cluster stability and performance. The regex circuit breaker limits the use and complexity of regex in Painless scripts.
(Static) Enables regex in Painless scripts. Accepts:
Enables regex but limits complexity using the
- Enables regex with no complexity limits. Disables the regex circuit breaker.
- Disables regex. Any Painless script containing a regular expression returns an error.
(Static) Limits the number of characters a regular expression in a Painless script can consider. Elasticsearch calculates this limit by multiplying the setting value by the script input’s character length.
For example, the input
foobarbazhas a character length of
6, a regular expression on
foobarbazcan consider up to 54 (9 * 6) characters. If the expression exceeds this limit, it triggers the regex circuit breaker and returns an error.
Elasticsearch only applies this limit if