Updated breaker settings for in-flight requests – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-7.8

Briefly, this error occurs when Elasticsearch updates the circuit breaker settings for in-flight requests. The circuit breaker is a mechanism to prevent out-of-memory errors by limiting the memory usage of certain operations. This message indicates that the settings for the in-flight requests breaker have been updated. To resolve this, you can adjust the breaker settings based on your system’s memory capacity. If you’re frequently hitting the limit, consider increasing your system’s memory or optimizing your queries to use less memory. Alternatively, you can disable the circuit breaker, but this may lead to out-of-memory errors.

To learn more abour updating breaker settings for inflight requests, we recommend you try running the Elasticsearch Error Check-Up. It will help you resolve any outstanding issues and check the configuration of all of your settings.

This guide will help you check for common problems that cause the log “Updated breaker settings for in-flight requests” to appear. It’s important to understand the issues related to the log, so to get started, read the general overview on common issues and tips related to the Elasticsearch concepts: breaker, circuit, indices and settings.

What this log means

This log message is an INFO message notifying you that the breaker settings for in-flight requests have been updated. You can check the updated values using this command:

GET /_cluster/settings?pretty&include_defaults

Or by running Opster’s Elasticsearch Error Check-Up to get an immediate review of your settings and configurations, with instructions for improvement. 

Be aware of the pros and cons of updating the circuit breaker settings.

The circuit breaker limit for in-flight requests can be increased and decreased dynamically. The default limit for in-flight requests breakers is set at 100% of the limit assigned to the parent circuit breaker. This means that by default the in-flight requests circuit breaker is allowed to take as much heap memory as allowed by the parent circuit breaker, not that the in-flight requests circuit breaker can take up to 100% of the whole heap memory. 

PUT /_cluster/settings
 "persistent": {
   "network.breaker.inflight_requests.limit": "99%"

The “overhead” setting is used to define the constant multiplier for byte estimations of the in-flight requests circuit breaker. The default value is 2.

PUT /_cluster/settings
 "persistent": {
   "network.breaker.inflight_requests.overhead": "1"

When the breaker settings for in-flight requests are updated, the following log is generated:

[INFO ][o.e.i.b.HierarchyCircuitBreakerService] Updated breaker settings for in-flight requests: [in_flight_requests,type=MEMORY,durability=TRANSIENT,limit=1063004405/1013.7mb,o

Log Context

Log “Updated breaker settings for in-flight requests: {}” classname is HierarchyCircuitBreakerService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        BreakerSettings newInFlightRequestsSettings = new BreakerSettings(CircuitBreaker.IN_FLIGHT_REQUESTS;
            newInFlightRequestsMax.getBytes(); newInFlightRequestsOverhead; this.inFlightRequestsSettings.getType();
        this.inFlightRequestsSettings = newInFlightRequestsSettings;
        logger.info("Updated breaker settings for in-flight requests: {}"; newInFlightRequestsSettings);

    private void setFieldDataBreakerLimit(ByteSizeValue newFielddataMax; Double newFielddataOverhead) {
        long newFielddataLimitBytes = newFielddataMax == null ?
            HierarchyCircuitBreakerService.this.fielddataSettings.getLimit() : newFielddataMax.getBytes();


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