Unknown serialized type ord – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch encounters an unknown serialized type during the deserialization process. This could be due to a mismatch between the types defined in your code and the types stored in Elasticsearch. To resolve this issue, you can: 1) Check your code for any discrepancies in type definitions and correct them. 2) Ensure that the version of Elasticsearch you’re using is compatible with the types you’re trying to deserialize. 3) If the error persists, consider reindexing your data after correcting the type definitions.

This guide will help you check for common problems that cause the log ” unknown serialized type [” + ord + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: search, index.

Log Context

Log “unknown serialized type [” + ord + “]” class name is MatchQueryParser.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 for (Type type : Type.values()) {
 if (type.ordinal == ord) {
 return type;
 throw new ElasticsearchException("unknown serialized type [" + ord + "]");
 }  @Override
 public void writeTo(StreamOutput out) throws IOException {


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