Briefly, this error occurs when Elasticsearch receives multiple results or errors for a single subject, which is against its design principle. It expects a one-to-one mapping between subjects and results or errors. This could be due to incorrect query formation or a bug in the application. To resolve this, ensure your queries are correctly formed and returning a single result per subject. If the problem persists, debug your application to identify and fix any potential bugs causing this issue. Also, ensure your Elasticsearch version is up-to-date as this could be a bug fixed in a newer version.
This guide will help you check for common problems that cause the log ” a single subject must have either a single result or error ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: plugin.
Log Context
Log “a single subject must have either a single result or error” class name is ProfileService.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
final Exception exception = resultsAndErrors.errors().values().iterator().next();
logger.error(exception.getMessage());
listener.onFailure(exception);
} else {
assert false : "a single subject must have either a single result or error";
listener.onFailure(new ElasticsearchException("a single subject must have either a single result or error"));
} }; listener::onFailure));
}
