resetting knn circuit breaker triggered

Question

How can we reset the knn circuit breaker when it is triggered. According to knn documentation we need to update a cluster setting but are for some reason denied access to this setting: knn.memory.circuit_breaker.limit

What is the work around?

iamlmt · Accepted Answer

Update on the answer, the "defaults" settings are not able to be changed but the "persistent" changes are able to be changed, the correct thing to do to evict and reset the KNN cache is to perform the following request:

HTTP PUT /_cluster/settings {"persistent":{"knn.memory.circuit_breaker.limit": null } }

HTTP PUT /_cluster/settings
{"persistent":{"knn.memory.circuit_breaker.limit": null } }

Arifc · Answer

Hi, 
As you mentioned yo need to reset the k-NN circuit breaker when it is triggered in Amazon OpenSearch Service, and the k-NN circuit breaker is controlled by the *knn.memory.circuit_breaker.limit* cluster setting, with this setting you can determine the maximum amount of memory that can be used by the k-NN feature.

A "denied access" error when trying to update this setting, could mean that you do not have the necessary permissions to modify the cluster settings.  You will need to request the appropriate IAM permissions from your AWS administrator. The required permissions are:
    "opensearch:UpdateDomainConfig"
    "opensearch:DescribeDomain"
    "opensearch:DescribeDomainConfig"

After you update the setting, the k-NN circuit breaker should be reset, and your queries should be able to execute without triggering the circuit breaker.

resetting knn circuit breaker triggered

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