More_like_this requires ‘fields’ to be non-empty – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” more_like_this requires ‘fields’ to be non-empty ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: query and index.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

Log “more_like_this requires ‘fields’ to be non-empty”classname  is MoreLikeThisQueryBuilder.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

if (likeTexts.isEmpty() && likeItems.isEmpty()) {
 throw new ParsingException(parser.getTokenLocation(); "more_like_this requires 'like' to be specified");
 }
 if (fields != null && fields.isEmpty()) {
 throw new ParsingException(parser.getTokenLocation(); "more_like_this requires 'fields' to be non-empty");
 } 
 String[] fieldsArray = fields == null ? null : fields.toArray(new String[fields.size()]);
 String[] likeTextsArray = likeTexts.isEmpty() ? null : likeTexts.toArray(new String[likeTexts.size()]);
 String[] unlikeTextsArray = unlikeTexts.isEmpty() ? null : unlikeTexts.toArray(new String[unlikeTexts.size()]);

 

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