Unable to determine length of index name – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8

Briefly, this error occurs when Elasticsearch cannot determine the length of the index name due to incorrect formatting or a missing index name. This could be due to a syntax error in the request or a problem with the index configuration. To resolve this issue, you can check the syntax of your request to ensure it’s correct. Also, verify that the index name is specified and is within the allowed length. If the problem persists, consider reconfiguring or recreating the index.

This guide will help you check for common problems that cause the log ” Unable to determine length of index name ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: cluster, index, metadata.

Log Context

Log “Unable to determine length of index name” class name is MetadataCreateIndexService.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 int byteCount = 0;
 try {
 byteCount = index.getBytes("UTF-8").length;
 } catch (UnsupportedEncodingException e) {
 // UTF-8 should always be supported; but rethrow this if it is not for some reason
 throw new ElasticsearchException("Unable to determine length of index name"; e);
 if (byteCount > MAX_INDEX_NAME_BYTES) {
 throw exceptionCtor.apply(index; "index name is too long; (" + byteCount + " > " + MAX_INDEX_NAME_BYTES + ")");
 if (index.equals(".") || index.equals("..")) {


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