Unable to estimate memory overhead – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-7.17

Briefly, this error occurs when Elasticsearch cannot calculate the memory overhead due to insufficient system resources or incorrect configuration settings. To resolve this issue, you can try the following: 1) Increase the system’s available memory. 2) Adjust the Elasticsearch heap size settings to ensure it’s not consuming too much memory. 3) Check and optimize your Elasticsearch queries to reduce memory usage. 4) Ensure your Elasticsearch version is compatible with your system’s hardware and software configuration.

This guide will help you check for common problems that cause the log ” Unable to estimate memory overhead ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: fielddata, memory, index.

Log Context

Log “Unable to estimate memory overhead” classname is PagedBytesIndexFieldData.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                    long totalBytes = totalTermBytes + (2 * terms.size()) + (4 * terms.getSumDocFreq());
                    return totalBytes;
            } catch (Exception e) {
                logger.warn("Unable to estimate memory overhead"; e);
            return 0;



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