prestodb/presto · error · IllegalArgumentException

Unsupported encoding

Error message

Unsupported encoding 

What it means

LongSelectiveStreamReader.startStripe validates that the stripe's stream encoding kind is one this reader supports (DIRECT, DIRECT_V2, DICTIONARY, etc.). When the stripe reports an unknown/unsupported encoding kind, the reader cannot decode it and throws IllegalArgumentException. This typically means the ORC/DWRF file uses an encoding the current Presto version does not implement.

Source

Thrown at presto-orc/src/main/java/com/facebook/presto/orc/reader/LongSelectiveStreamReader.java:93

                }
                currentReader = directReader;
                if (dictionaryReader != null && context.isResetAllReaders()) {
                    dictionaryReader = null;
                    System.setProperty("RESET_LONG_READER", "RESET_LONG_READER");
                }
                break;
            case DICTIONARY:
                if (dictionaryReader == null) {
                    dictionaryReader = new LongDictionarySelectiveStreamReader(context);
                }
                currentReader = dictionaryReader;
                if (directReader != null && context.isResetAllReaders()) {
                    directReader = null;
                    System.setProperty("RESET_LONG_READER", "RESET_LONG_READER");
                }
                break;
            default:
                throw new IllegalArgumentException("Unsupported encoding " + kind);
        }

        currentReader.startStripe(timezone, stripe);
    }

    @Override
    public void startRowGroup(InputStreamSources dataStreamSources)
            throws IOException
    {
        currentReader.startRowGroup(dataStreamSources);
    }

    @Override
    public String toString()
    {
        return toStringHelper(this)
                .addValue(context.getStreamDescriptor())
                .toString();

View on GitHub (pinned to 55bb57d202)

Solutions

1. Inspect the file's writer version and column encodings (orc-tools `meta` / ORC footer dump) to confirm which encoding kind is present.
2. Upgrade Presto to a version that supports the encoding used by the file.
3. Re-write the file with a compatible writer (e.g. `SET hive.exec.orc.encoding.style` or rewrite via Hive/Spark with default encodings).
4. If the kind is bogus due to corruption, re-copy/regenerate the file and validate checksums.

ColumnEncoding encoding = stripe.getColumnEncodings().get(columnId);
if (!SUPPORTED_LONG_KINDS.contains(encoding.getKind())) {
    throw new IllegalArgumentException("Stripe encoding " + encoding.getKind() + " unsupported for long column");
}

boolean isSupportedLongEncoding(ColumnEncodingKind kind) {
    return kind == DIRECT || kind == DIRECT_V2 || kind == DICTIONARY || kind == DICTIONARY_V2;
}

try {
    reader.startStripe(timezone, stripe);
}
catch (IllegalArgumentException e) {
    throw new PrestoException(ORC_BAD_DATA, "Unsupported stripe encoding for long column: " + e.getMessage(), e);
}

When it happens

Trigger: Reading a stripe whose ColumnEncoding kind falls into the default branch — e.g. a DWRF-specific or newer encoding written by a newer writer version being read by an older Presto.

Common situations: Cross-version file interchange: files written by newer Facebook DWRF writers or other engines read by an older Presto; corrupted stripe metadata in the ORC footer causing a bogus encoding kind; custom forks adding encodings not present upstream.

Related errors

• Unsupported encoding
• Encrypted data size %s exceeds limit of 2^23
• Stripe encryption keys are missing, but file is encrypted
• Number of stripe encryption keys did not match number of enc
• Invalid ORC metadata %s or DWRF stripe cache size %s

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/71e67510c8d9fb45. Report an issue: GitHub.