Updating min merge size from mb to – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 1.7-1.7

Briefly, this error occurs when Elasticsearch is trying to update the minimum merge size for its indices, but the new value is not specified or is invalid. This could be due to a configuration error or a bug in the software. To resolve this issue, you can check your Elasticsearch configuration for any errors related to the min merge size setting. If the error persists, consider updating or reinstalling Elasticsearch to ensure you’re running a version without this bug.

This guide will help you check for common problems that cause the log ” updating min_merge_size from [{}mb] to [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index and merge.

Log Context

Log “updating min_merge_size from [{}mb] to [{}]” classname is LogByteSizeMergePolicyProvider.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        public void onRefreshSettings(Settings settings) {
            double oldMinMergeSizeMB = mergePolicy.getMinMergeMB();
            ByteSizeValue minMergeSize = settings.getAsBytesSize(INDEX_MERGE_POLICY_MIN_MERGE_SIZE; null);
            if (minMergeSize != null && minMergeSize.mbFrac() != oldMinMergeSizeMB) {
                logger.info("updating min_merge_size from [{}mb] to [{}]"; oldMinMergeSizeMB; minMergeSize);

            double oldMaxMergeSizeMB = mergePolicy.getMaxMergeMB();
            ByteSizeValue maxMergeSize = settings.getAsBytesSize(INDEX_MERGE_POLICY_MAX_MERGE_SIZE; null);


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