Failed to generate filter – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch fails to generate a specific filter due to incorrect syntax, missing fields, or invalid values. To resolve this issue, you should first verify the syntax of your filter query. Ensure that all necessary fields are included and that the values provided are valid and in the correct format. If the error persists, consider simplifying your filter or breaking it down into smaller parts to identify the problematic section.

This guide will help you check for common problems that cause the log ” Failed to generate [” + filter + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: admin, alias, filter, indices.

Log Context

Log “Failed to generate [” + filter + “]” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 XContentBuilder builder = XContentFactory.contentBuilder(XContentType.JSON);;
 this.filter = Strings.toString(builder);
 return this;
 } catch (IOException e) {
 throw new ElasticsearchGenerationException("Failed to generate [" + filter + "]"; e);
 }  public AliasActions filter(QueryBuilder filter) {
 if (filter == null) {