Malformed regular expression file should continue with field name after array – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch encounters a malformed regular expression file. It expects a ‘field_name’ after ‘array’ but it’s not present. This could be due to a syntax error or incorrect formatting in the regular expression file. To resolve this issue, you should review the regular expression file and correct any syntax or formatting errors. Ensure that the ‘field_name’ follows ‘array’ as expected. Additionally, validate your regular expression file using a regex validator to catch any hidden errors.

This guide will help you check for common problems that cause the log ” malformed regular expression file; should continue with ‘field_name’ after ‘array’ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .

Log Context

Log “malformed regular expression file; should continue with ‘field_name’ after ‘array'” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 while (token == XContentParser.Token.START_OBJECT) {
 token = yamlParser.nextToken();  if (token != XContentParser.Token.FIELD_NAME) {
 throw new ElasticsearchParseException("malformed regular expression file; should continue with 'field_name' after 'array'");
 }  Map regexMap = new HashMap<>();
 for (; token == XContentParser.Token.FIELD_NAME; token = yamlParser.nextToken()) {
 String fieldName = yamlParser.currentName();


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