Aggregation definition for aggregationName starts with a – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.15

Before you dig into reading this guide, have you tried asking OpsGPT what this log means? You’ll receive a customized analysis of your log.

Try OpsGPT now for step-by-step guidance and tailored insights into your Elasticsearch operation.

Briefly, this error occurs when the name of an aggregation in Elasticsearch starts with a bracket “[“. Elasticsearch doesn’t allow special characters like brackets in the name of an aggregation. To resolve this issue, you can rename the aggregation without using any special characters. Alternatively, you can use the escape character “\” before the bracket if you want to keep it in the name. However
try for free AutoOps for Elasticsearch & OpenSearch . With AutoOps and Opster’s proactive support

Log Context

Log “Aggregation definition for [” + aggregationName + ” starts with a [” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 + "]. Aggregation names can contain any character except '['; ']'; and '>'");
 }  token = parser.nextToken();
 if (token != XContentParser.Token.START_OBJECT) {
 throw new ParsingException(parser.getTokenLocation(); "Aggregation definition for [" + aggregationName + " starts with a ["
 + token + "]; expected a [" + XContentParser.Token.START_OBJECT + "].");
 }  BaseAggregationBuilder aggBuilder = null;
 AggregatorFactories.Builder subFactories = null;


How helpful was this guide?

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?