UTF-8 – How to solve this OpenSearch error

Opster Team

Aug-23, Version: 1-2.9

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Briefly, this error occurs when OpenSearch encounters data that is not in the UTF-8 format. UTF-8 is a universal character encoding standard that OpenSearch uses to interpret and store data. If the data is not in this format, OpenSearch will throw an error. To resolve this issue, you can convert your data to UTF-8 format before indexing it. Alternatively, you can specify the correct character encoding in your content-type header when sending data to OpenSearch. Lastly, ensure that your OpenSearch cluster is configured to handle non-UTF-8 data if necessary.

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This guide will help you check for common problems that cause the log ” UTF-8 ” to appear. To understand the issues related to this log, read the explanation below about the following OpenSearch concepts: .

Log Context

Log “UTF-8” classname is LoggedExec.java.
We extracted the following from OpenSearch source code for those seeking an in-depth context :

        } else {
            out = new ByteArrayOutputStream();
            outputLogger = logger -> {
                try {
                    logger.error(((ByteArrayOutputStream) out).toString("UTF-8"));
                } catch (UnsupportedEncodingException e) {
                    throw new RuntimeException(e);


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