Field masking span query must be of type span query – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.14

Briefly, this error occurs when a [field_masking_span] query is used in Elasticsearch, but the query inside it is not of type span. The [field_masking_span] query is designed to work with span queries only. To resolve this issue, ensure that the query inside the [field_masking_span] is a span query. If it’s not, you need to rewrite it as a span query or use a different type of query that is compatible with your current query type.

This guide will help you check for common problems that cause the log ” [field_masking_span] query must be of type span query ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: query, index.

Log Context

Log “[field_masking_span] query must be of type span query” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 currentFieldName = parser.currentName();
 } else if (token == XContentParser.Token.START_OBJECT) {
 if (QUERY_FIELD.match(currentFieldName; parser.getDeprecationHandler())) {
 QueryBuilder query = parseInnerQueryBuilder(parser);
 if (query instanceof SpanQueryBuilder == false) {
 throw new ParsingException(parser.getTokenLocation(); "[field_masking_span] query must be of type span query");
 inner = (SpanQueryBuilder) query;
 checkNoBoost(NAME; currentFieldName; parser; inner);
 } else {
 throw new ParsingException(parser.getTokenLocation(); "[field_masking_span] query does not support ["