Sequence fork is unsupported – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 7.8-7.9

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Briefly, this error occurs when Elasticsearch tries to execute a sequence fork operation, which is not supported. This could be due to incorrect configuration or misuse of Elasticsearch APIs. To resolve this issue, you can review your Elasticsearch queries and operations to ensure they are compatible with the version you are using. Also, check your cluster settings and configurations to ensure they are correctly set. If the problem persists, consider upgrading your Elasticsearch version or seeking help from the Elasticsearch community.

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This guide will help you check for common problems that cause the log ” sequence fork is unsupported ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: parser, plugin.

Log Context

Log “sequence fork is unsupported” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 return new Sequence(source; queries; until; maxSpan; fieldTimestamp(); fieldTiebreaker(); defaultDirection());
 }  public KeyedFilter visitSequenceTerm(SequenceTermContext ctx; List joinKeys) {
 if (ctx.FORK() != null) {
 throw new ParsingException(source(ctx.FORK()); "sequence fork is unsupported");
 }  return keyedFilter(joinKeys; ctx;; ctx.subquery());


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