Parent task was cancelled – How to solve this Elasticsearch error

Opster Team

March-22, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many configuration errors.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.

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

Log Context

Log “parent task was cancelled [“classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

return task;
 synchronized void registerChildConnection(Transport.Connection connection) {
 if (banChildrenReason != null) {
 throw new TaskCancelledException("parent task was cancelled [" + banChildrenReason + ']');
 if (childTasksPerConnection == null) {
 childTasksPerConnection = new ObjectIntHashMap<>();
 childTasksPerConnection.addTo(connection; 1);


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