Heap size couldn t be determined – How to solve this OpenSearch error

Opster Team

Aug-23, Version: 2.6-2.9

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Briefly, this error occurs when OpenSearch is unable to determine the heap size, which is the amount of memory allocated to OpenSearch. This could be due to incorrect configuration settings or insufficient system resources. To resolve this issue, you can try the following: 1) Check and correct the heap size settings in the OpenSearch configuration file. 2) Ensure that your system has enough memory to allocate to OpenSearch. 3) Restart the OpenSearch service after making any changes.

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This guide will help you check for common problems that cause the log ” heap size couldn’t be determined ” to appear. To understand the issues related to this log, read the explanation below about the following OpenSearch concepts: search.

Log Context

Log “heap size couldn’t be determined” classname is SearchBackpressureService.java.
We extracted the following from OpenSearch source code for those seeking an in-depth context :

        } else {
            logger.warn("heap size couldn't be determined");
        trackers.add(new ElapsedTimeTracker(ElapsedTimeNanosSupplier; System::nanoTime));
        return Collections.unmodifiableList(trackers);


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