Failed to create aggregators – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch is unable to create aggregators due to reasons like insufficient memory, complex queries, or incorrect aggregation syntax. To resolve this, you can increase the heap size to provide more memory, simplify your queries to reduce complexity, or check your aggregation syntax for any errors. Also, ensure that your Elasticsearch version supports the aggregations you’re trying to use.

This guide will help you check for common problems that cause the log ” Failed to create aggregators ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: search.

Log Context

Log “Failed to create aggregators” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 try {
 AggregatorFactories factories = source.aggregations().build(aggContext; null);
 context.aggregations(new SearchContextAggregations(factories));
 } catch (IOException e) {
 throw new AggregationInitializationException("Failed to create aggregators"; e);
 if (source.suggest() != null) {
 try {