Error parsing wildcard regex pattern fragment fragment – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.9-8.9

Briefly, this error occurs when Elasticsearch encounters an issue while parsing a wildcard regex pattern fragment. This could be due to an invalid or unsupported regex pattern. To resolve this issue, you can first verify the regex pattern for any syntax errors. Ensure that the pattern is correctly formatted and supported by Elasticsearch. If the pattern is complex, try simplifying it or breaking it down into smaller parts. Also, ensure that any special characters are properly escaped. If the error persists, consider using a different method to achieve the same result.

This guide will help you check for common problems that cause the log ” Error parsing wildcard regex pattern fragment [” + fragment + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.

Log Context

Log “Error parsing wildcard regex pattern fragment [” + fragment + “]” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 } catch (IOException ioe) {
 throw new ElasticsearchParseException("Error parsing wildcard regex pattern fragment [" + fragment + "]");
 }  if (foundTokens == 0 && fragment.length() > 0) {
 // fragment must have been less than NGRAM_SIZE - add a placeholder which may be used in a prefix query e.g. ab*
 fragment = toLowerCase(fragment);


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