Unexpected error while releasing pipelined http responses – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch encounters an issue while trying to release pipelined HTTP responses. This could be due to network issues, server overload, or a bug in the Elasticsearch software. To resolve this issue, you can try the following: 1) Check your network connection and ensure it’s stable. 2) Monitor your server’s load and resources, and scale up if necessary. 3) Update Elasticsearch to the latest version to fix any potential bugs. 4) Check your Elasticsearch logs for more detailed error messages that can help pinpoint the problem.

This guide will help you check for common problems that cause the log ” unexpected error while releasing pipelined http responses ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: .

Log Context

Log “unexpected error while releasing pipelined http responses” classname is Netty4HttpPipeliningHandler.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

    private void safeFailPromise(ChannelPromise promise; Exception ex) {
        try {
        } catch (RuntimeException e) {
            logger.error("unexpected error while releasing pipelined http responses"; e);

    private Future enqueueWrite(ChannelHandlerContext ctx; HttpObject msg) {
        final ChannelPromise p = ctx.newPromise();