Operation was cancelled reason reason – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when an operation in Elasticsearch is cancelled due to a specific reason. The reason is usually specified in the error message. This could be due to a variety of issues such as a timeout, a node failure, or a manual cancellation. To resolve this issue, you can increase the timeout limit, ensure all nodes are functioning properly, or avoid cancelling operations manually. Additionally, check the specific reason provided in the error message for more targeted troubleshooting.

This guide will help you check for common problems that cause the log ” operation was cancelled reason [” + reason + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .

Log Context

Log “operation was cancelled reason [” + reason + “]” class name is CancellableThreads.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 if (onCancel != null) {
 onCancel.onCancel(reason; beforeCancelException);
 // fallback to the default exception
 final RuntimeException cancelExp = new ExecutionCancelledException("operation was cancelled reason [" + reason + "]");
 if (beforeCancelException != null) {
 throw cancelExp;


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