Unknown operator – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many configuration errors.

Briefly, this error indicates that an unknown operator is used in the Elasticsearch query. Elasticsearch supports a wide range of operators like AND, OR, and NOT, and using an unknown operator can cause the query to fail. To resolve this error, review the query syntax and ensure that the operator used is valid and compatible with the Elasticsearch version in use.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.

This guide will help you check for common problems that cause the log ” Unknown operator ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: parser and plugin.

Log Context

Log “Unknown operator {}”classname  is ExpressionBuilder.java We extracted the following from Elasticsearch source code for those seeking an in-depth context :

case EqlBaseParser.GT:
 return new GreaterThan(source; left; right; zoneId);
 case EqlBaseParser.GTE:
 return new GreaterThanOrEqual(source; left; right; zoneId);
 throw new ParsingException(source; "Unknown operator {}"; source.text());
 public Expression visitValueExpressionDefault(ValueExpressionDefaultContext ctx) {


See how you can use AutoOps to resolve issues

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