Failed to parse term vectors request field fields must be an array – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch receives a term vectors request with a field parameter that is not formatted as an array. Elasticsearch expects the ‘fields’ parameter to be an array, but it received a different data type, causing the parsing to fail. To resolve this issue, you should review your term vectors request and ensure that the ‘fields’ parameter is correctly formatted as an array. This typically involves enclosing the field names in square brackets. For example, instead of “fields”: “field1”, use “fields”: [“field1”].

This guide will help you check for common problems that cause the log ” failed to parse term vectors request. field [fields] must be an array ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: request.

Log Context

Log “failed to parse term vectors request. field [fields] must be an array” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 if (token == XContentParser.Token.START_ARRAY) {
 while (parser.nextToken() != XContentParser.Token.END_ARRAY) {
 } else {
 throw new ElasticsearchParseException("failed to parse term vectors request. field [fields] must be an array");
 } else if (OFFSETS.match(currentFieldName; parser.getDeprecationHandler())) {
 } else if (POSITIONS.match(currentFieldName; parser.getDeprecationHandler())) {


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