Expecting the analyzer at to be a String but found instead – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7-7.15

Briefly, this error occurs when Elasticsearch expects an analyzer to be defined as a string, but encounters a different data type instead. This could be due to incorrect configuration or syntax in the mapping or settings. To resolve this, ensure that the analyzer is correctly defined as a string in your settings. Also, check your mapping and ensure that the field you’re trying to analyze is of type ‘text’ and not ‘keyword’ or any other non-analyzable type.

This guide will help you check for common problems that cause the log ” expecting the analyzer at [{}] to be a String; but found [{}] instead ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .

Log Context

Log “expecting the analyzer at [{}] to be a String; but found [{}] instead” class name is TermVectorsRequest.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 Map mapStrStr = new HashMap<>();
 for (Map.Entry e : map.entrySet()) {
 if (e.getValue() instanceof String) {
 mapStrStr.put(e.getKey(); (String) e.getValue());
 } else {
 throw new ElasticsearchParseException("expecting the analyzer at [{}] to be a String; but found [{}] instead";
 e.getKey(); e.getValue().getClass());
 return mapStrStr;


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