118 lines
4.3 KiB
Plaintext
118 lines
4.3 KiB
Plaintext
[[circuit-breaker]]
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=== Circuit Breaker
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Elasticsearch contains multiple circuit breakers used to prevent operations from
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causing an OutOfMemoryError. Each breaker specifies a limit for how much memory
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it can use. Additionally, there is a parent-level breaker that specifies the
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total amount of memory that can be used across all breakers.
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These settings can be dynamically updated on a live cluster with the
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<<cluster-update-settings,cluster-update-settings>> API.
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[[parent-circuit-breaker]]
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[float]
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==== Parent circuit breaker
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The parent-level breaker can be configured with the following settings:
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`indices.breaker.total.use_real_memory`::
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Whether the parent breaker should take real memory usage into account (`true`) or only
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consider the amount that is reserved by child circuit breakers (`false`). Defaults to `true`.
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`indices.breaker.total.limit`::
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Starting limit for overall parent breaker, defaults to 70% of JVM heap if
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`indices.breaker.total.use_real_memory` is `false`. If `indices.breaker.total.use_real_memory`
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is `true`, defaults to 95% of the JVM heap.
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[[fielddata-circuit-breaker]]
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[float]
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==== Field data circuit breaker
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The field data circuit breaker allows Elasticsearch to estimate the amount of
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memory a field will require to be loaded into memory. It can then prevent the
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field data loading by raising an exception. By default the limit is configured
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to 40% of the maximum JVM heap. It can be configured with the following
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parameters:
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`indices.breaker.fielddata.limit`::
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Limit for fielddata breaker, defaults to 40% of JVM heap
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`indices.breaker.fielddata.overhead`::
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A constant that all field data estimations are multiplied with to determine a
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final estimation. Defaults to 1.03
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[[request-circuit-breaker]]
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[float]
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==== Request circuit breaker
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The request circuit breaker allows Elasticsearch to prevent per-request data
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structures (for example, memory used for calculating aggregations during a
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request) from exceeding a certain amount of memory.
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`indices.breaker.request.limit`::
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Limit for request breaker, defaults to 60% of JVM heap
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`indices.breaker.request.overhead`::
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A constant that all request estimations are multiplied with to determine a
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final estimation. Defaults to 1
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[[in-flight-circuit-breaker]]
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[float]
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==== In flight requests circuit breaker
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The in flight requests circuit breaker allows Elasticsearch to limit the memory usage of all
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currently active incoming requests on transport or HTTP level from exceeding a certain amount of
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memory on a node. The memory usage is based on the content length of the request itself. This
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circuit breaker also considers that memory is not only needed for representing the raw request but
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also as a structured object which is reflected by default overhead.
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`network.breaker.inflight_requests.limit`::
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Limit for in flight requests breaker, defaults to 100% of JVM heap. This means that it is bound
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by the limit configured for the parent circuit breaker.
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`network.breaker.inflight_requests.overhead`::
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A constant that all in flight requests estimations are multiplied with to determine a
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final estimation. Defaults to 2.
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[[accounting-circuit-breaker]]
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[float]
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==== Accounting requests circuit breaker
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The accounting circuit breaker allows Elasticsearch to limit the memory
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usage of things held in memory that are not released when a request is
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completed. This includes things like the Lucene segment memory.
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`indices.breaker.accounting.limit`::
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Limit for accounting breaker, defaults to 100% of JVM heap. This means that it is bound
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by the limit configured for the parent circuit breaker.
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`indices.breaker.accounting.overhead`::
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A constant that all accounting estimations are multiplied with to determine a
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final estimation. Defaults to 1
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[[script-compilation-circuit-breaker]]
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[float]
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==== Script compilation circuit breaker
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Slightly different than the previous memory-based circuit breaker, the script
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compilation circuit breaker limits the number of inline script compilations
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within a period of time.
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See the "prefer-parameters" section of the <<modules-scripting-using,scripting>>
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documentation for more information.
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`script.max_compilations_rate`::
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Limit for the number of unique dynamic scripts within a certain interval
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that are allowed to be compiled. Defaults to 75/5m, meaning 75 every 5
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minutes.
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