prestodb/presto · error · SQLFeatureNotSupportedException

getNCharacterStream

Error message

getNCharacterStream

What it means

PrestoResultSet.getNCharacterStream(int) is a JDBC 4 national-character stream accessor that Presto's driver intentionally does not support; it throws SQLFeatureNotSupportedException naming the method. Presto has no NCHAR-family SQL types, so no character-stream implementation exists.

Source

Thrown at presto-jdbc/src/main/java/com/facebook/presto/jdbc/PrestoResultSet.java:1412

    @Override
    public String getNString(int columnIndex)
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("getNString");
    }

    @Override
    public String getNString(String columnLabel)
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("getNString");
    }

    @Override
    public Reader getNCharacterStream(int columnIndex)
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("getNCharacterStream");
    }

    @Override
    public Reader getNCharacterStream(String columnLabel)
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("getNCharacterStream");
    }

    @Override
    public void updateNCharacterStream(int columnIndex, Reader x, long length)
            throws SQLException
    {
        throw new SQLFeatureNotSupportedException("updateNCharacterStream");
    }

    @Override
    public void updateNCharacterStream(String columnLabel, Reader reader, long length)

View on GitHub (pinned to 55bb57d202)

Solutions

1. Use getCharacterStream(int columnIndex) if a stream is needed, or getString for the full text
2. Refactor the data-access layer to the standard character APIs supported by Presto
3. Check driver capability (DatabaseMetaData) before calling JDBC 4-only methods

Example fix

// before
Reader r = rs.getNCharacterStream(3);
// after
Reader r = rs.getCharacterStream(3);

if (conn.getMetaData().getDatabaseProductName().contains("Presto")) {
    useStandardCharStream = true;
}

boolean supportsNCharStream(ResultSet rs) {
    return !(rs instanceof com.facebook.presto.jdbc.PrestoResultSet);
}

try {
    reader = rs.getNCharacterStream(3);
} catch (SQLFeatureNotSupportedException e) {
    reader = rs.getCharacterStream(3);
}

When it happens

Trigger: Calling getNCharacterStream(int columnIndex) on a Presto result set. Throws unconditionally on every invocation.

Common situations: Generic JDBC tooling or code ported from databases with national character types; readers streaming large text columns assuming JDBC 4 N-stream APIs are available.

Related errors

• Result set type must be TYPE_FORWARD_ONLY
• Result set concurrency must be CONCUR_READ_ONLY
• Result set holdability must be HOLD_CURSORS_OVER_COMMIT
• privileges not supported
• row identifiers not supported

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/b8886ff4d5025afd. Report an issue: GitHub.