Briefly, this error occurs when Elasticsearch is unable to notify the response handler about a connection closure. This could be due to network issues, overloaded server, or a bug in the Elasticsearch software. To resolve this issue, you can try restarting Elasticsearch, checking your network connection, or upgrading Elasticsearch to the latest version. If the server is overloaded, consider scaling up your resources or optimizing your queries to reduce load.
This guide will help you check for common problems that cause the log ” failed to notify response handler on connection close [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: handler, response.
Log Context
Log “failed to notify response handler on connection close [{}]” classname is TransportService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
}
@Override
public void onFailure(Exception e) {
assert false : e;
logger.warn(() -> new ParameterizedMessage("failed to notify response handler on connection close [{}]"; connection); e);
}
@Override
public String toString() {
return "onConnectionClosed(" + connection.getNode() + ")";
