Reverse nested nested path path is not nested – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8

Briefly, this error occurs when a reverse_nested aggregation is used on a field that is not nested. Elasticsearch expects the field to be of nested type for this operation. To resolve this issue, you can either change the field type to nested in your mapping or use a different aggregation that doesn’t require a nested field. Alternatively, you can restructure your data to avoid the need for reverse_nested aggregation.

This guide will help you check for common problems that cause the log ” [reverse_nested] nested path [” + path + “] is not nested ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: search, aggregations.

Log Context

Log “[reverse_nested] nested path [” + path + “] is not nested” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 parentObjectMapper = context.getObjectMapper(path);
 if (parentObjectMapper == null) {
 return new ReverseNestedAggregatorFactory(name; true; null; context; parent; subFactoriesBuilder; metadata);
 if (parentObjectMapper.isNested() == false) {
 throw new AggregationExecutionException("[reverse_nested] nested path [" + path + "] is not nested");
 }  NestedScope nestedScope = context.nestedScope();
 NestedObjectMapper nestedMapper = (NestedObjectMapper) parentObjectMapper;


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