Key doc count – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-6.8

Briefly, this error occurs when Elasticsearch is unable to find the ‘doccount’ key in the response. This key is usually part of an aggregation query and its absence could be due to a malformed query or a change in the data structure. To resolve this issue, you can 1) Review your aggregation query to ensure it’s correctly formed. 2) Check your data structure to ensure it matches the query. 3) Update your Elasticsearch version if it’s outdated, as older versions may not support certain features. 4) Reindex your data if it has changed significantly.

This guide will help you check for common problems that cause the log ” Key [{}]; doc_count [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: aggregations.

Log Context

Log “Key [{}]; doc_count [{}]” classname is tophits-aggregation.asciidoc.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

// For each entry
for (Terms.Bucket entry : agg.getBuckets()) {
    String key = entry.getKey();                    // bucket key
    long docCount = entry.getDocCount();            // Doc count"key [{}]; doc_count [{}]"; key; docCount);

    // We ask for top_hits for each bucket
    TopHits topHits = entry.getAggregations().get("top");
    for (SearchHit hit : topHits.getHits().getHits()) {" -> id [{}]; _source [{}]"; hit.getId(); hit.getSourceAsString());


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