prestodb/presto · error · IllegalArgumentException

escape not implemented

Error message

escape not implemented

What it means

Text StringEncoding writes values verbatim and only knows how to handle the field delimiter; if an escape byte is configured and the value contains the escape character, escaping is not implemented, so encodeColumn throws IllegalArgumentException rather than producing ambiguous output.

Source

Thrown at presto-rcfile/src/main/java/com/facebook/presto/rcfile/text/StringEncoding.java:51

    public StringEncoding(Type type, Slice nullSequence, Byte escapeChar)
    {
        this.type = type;
        this.nullSequence = nullSequence;
        this.escapeByte = escapeChar;
    }

    @Override
    public void encodeColumn(Block block, SliceOutput output, EncodeOutput encodeOutput)
    {
        for (int position = 0; position < block.getPositionCount(); position++) {
            if (block.isNull(position)) {
                output.writeBytes(nullSequence);
            }
            else {
                Slice slice = type.getSlice(block, position);
                if (escapeByte != null && slice.indexOfByte(escapeByte) < 0) {
                    throw new IllegalArgumentException("escape not implemented");
                }
                output.writeBytes(slice);
            }
            encodeOutput.closeEntry();
        }
    }

    @Override
    public void encodeValueInto(int depth, Block block, int position, SliceOutput output)
    {
        Slice slice = type.getSlice(block, position);
        if (escapeByte != null && slice.indexOfByte(escapeByte) < 0) {
            throw new IllegalArgumentException("escape not implemented");
        }
        output.writeBytes(slice);
    }

    @Override

View on GitHub (pinned to 55bb57d202)

Solutions

1. Remove the escape character from the table definition (use a format without escaping)
2. Pre-process data to strip or replace occurrences of the escape byte before writing
3. Switch the table to ORC/Parquet or a text format with proper escape support
4. Catch IllegalArgumentException and reject/sanitize the offending rows

Example fix

// before
CREATE TABLE t (s varchar) WITH (format='RCFILE', text_escape='\\');
// after
CREATE TABLE t (s varchar) WITH (format='RCFILE'); -- escape removed, or sanitize s first

// before writing a varchar column when escape is configured
Slice slice = type.getSlice(block, position);
if (escapeByte != null && slice.indexOfByte(escapeByte) >= 0) {
    // sanitize: strip/replace escape byte, or choose a different format
    slice = replaceByte(slice, escapeByte, (byte) ' ');
}

try { stringEncoding.encodeColumn(block, output, encodeOutput); }
catch (IllegalArgumentException e) {
    if (e.getMessage().equals("escape not implemented")) {
        encodeColumn(sanitize(block, escapeByte), output, encodeOutput); // strip escape and retry
    } else { throw e; }
}

When it happens

Trigger: encodeColumn on a VARCHAR column where escapeByte != null and the slice contains that escape byte — e.g. writing data containing '\' (or the configured escape) to a text RCFile with escaping enabled.

Common situations: Tables defined with an escape character (like TSV/CSV-style escaping) receiving user data containing that character; ETL jobs migrating free-text data into escaped RCFile tables.

Related errors

• HIVE_WRITER_CLOSE_ERROR
• HIVE_WRITER_OPEN_ERROR
• Invalid double value
• Invalid float value
• GENERIC_INTERNAL_ERROR

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/f4b9176de677d273. Report an issue: GitHub.