Failed to build aggregation aggregator name – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch fails to construct an aggregation due to issues like incorrect syntax, invalid field names, or insufficient memory. To resolve this, ensure that the aggregation query is correctly formatted and the field names used exist in your index. Also, check if there’s enough heap memory allocated to Elasticsearch. If not, consider increasing the heap size. However, be cautious not to exceed 50% of your total system memory to avoid swapping.

This guide will help you check for common problems that cause the log ” Failed to build aggregation [” + + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: search, aggregations.

Log Context

Log “Failed to build aggregation [” + + “]” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 for (Aggregator aggregator : context.aggregations().aggregators()) {
 try {
 } catch (IOException e) {
 throw new AggregationExecutionException("Failed to build aggregation [" + + "]"; e);
 // release the aggregator to claim the used bytes as we don't need it anymore


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