Pattern must not be null – 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 Check-Up which can resolve issues that cause many errors.

This guide will help you check for common problems that cause the log ” Pattern must not be null ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: parser and plugin.

Advanced users might want to skip right to the common problems section in each concept or try running the Check-Up to analyze Elasticsearch configuration and help resolve this error.

Log Context

Log “Pattern must not be [null]”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

return null;
 String pattern = string(ctx.value);
 if (pattern == null) {
 throw new ParsingException(source(ctx.value); "Pattern must not be [null]");
 int pos = pattern.indexOf('*');
 if (pos >= 0) {
 throw new ParsingException(source(ctx.value);
 "Invalid char [*] found in pattern [{}] at position {}; use [%] or [_] instead";


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