Unexpected exception while completing write task after delay – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.6-8.9

Briefly, this error occurs when Elasticsearch encounters an unexpected issue while trying to complete a write task after a delay. This could be due to a variety of reasons such as insufficient disk space, network issues, or a problem with the underlying storage system. To resolve this issue, you can try freeing up disk space, checking the network connectivity, or investigating the health of your storage system. Additionally, check the Elasticsearch logs for more detailed information about the error. It’s also advisable to ensure your Elasticsearch version is up-to-date as this could be a bug that’s been fixed in a newer version.

This guide will help you check for common problems that cause the log ” unexpected exception while completing write task after delay ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: task, bulk.

Log Context

Log “unexpected exception while completing write task after delay” classname is WriteAckDelay.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            logger.trace("completing {} writes"; tasks.size());
            for (Runnable task : tasks) {
                try {
                } catch (Exception e) {
                    logger.error("unexpected exception while completing write task after delay"; e);


How helpful was this guide?

We are sorry that this post was not useful for you!

Let us improve this post!

Tell us how we can improve this post?