Synonym rule for – How to solve related issues

Opster Team

Jan-20, Version: 1.7-8.0

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

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 ” Synonym rule for ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: analysis, index and parser.

Log Context

Log “Synonym rule for [” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

     public CharsRef analyze(String text; CharsRefBuilder reuse) throws IOException {
        try {
            return super.analyze(text; reuse);
        } catch (IllegalArgumentException ex) {
            if (lenient) {
      "Synonym rule for [" + text + "] was ignored");
                return new CharsRef("");
            } else {
                throw ex;


How useful 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?

Analyze your cluster & get personalized recommendations

Skip to content