prestodb/presto · error · PrestoException

NOT_SUPPORTED

NOT_SUPPORTED

Error message

Unsupported type 

What it means

Row.valueFromString converts a String token into a Java value for the given Presto Type; when the schema column's type has no conversion branch it throws NOT_SUPPORTED with 'Unsupported type <type>'. It is invoked per-field by Row.fromString, so one unsupported column type fails the whole row parse.

Source

Thrown at presto-accumulo/src/main/java/com/facebook/presto/accumulo/model/Row.java:235

            return Short.parseShort(str);
        }
        else if (type.equals(TIME)) {
            return Time.valueOf(LocalTime.parse(str, TIME_PARSER));
        }
        else if (type.equals(TIMESTAMP)) {
            return Timestamp.valueOf(LocalDateTime.parse(str, TIMESTAMP_PARSER));
        }
        else if (type.equals(TINYINT)) {
            return Byte.valueOf(str);
        }
        else if (type.equals(VARBINARY)) {
            return str.getBytes(UTF_8);
        }
        else if (type instanceof VarcharType) {
            return str;
        }
        else {
            throw new PrestoException(NOT_SUPPORTED, "Unsupported type " + type);
        }
    }
}

View on GitHub (pinned to 55bb57d202)

Solutions

1. Remove or exclude the unsupported column from the RowSchema being deserialized
2. Cast the column type in metadata to a supported type (e.g. cast array to VARCHAR before storage)
3. Add a conversion branch in valueFromString for the type (fork/maintenance path)
4. Use LexicoderRowSerializer instead of String-based deserialization, since it supports complex types

Example fix

// before
else {
    throw new PrestoException(NOT_SUPPORTED, "Unsupported type " + type);
}
// after
else if (type instanceof DecimalType) {
    return new BigDecimal(str);
} else {
    throw new PrestoException(NOT_SUPPORTED, "Unsupported type " + type);
}

for (int i = 0; i < schema.getLength(); i++) {
    Type t = schema.getColumn(i).getType();
    if (!(t instanceof VarcharType) && !SUPPORTED_ROW_TYPES.contains(t)) {
        throw new IllegalArgumentException("Column " + schema.getColumn(i).getName() + " has unsupported type " + t);
    }
}

static boolean isRowDecodableType(Type t) {
    return t instanceof VarcharType || t.equals(BOOLEAN) || t.equals(BIGINT) || t.equals(DOUBLE) || t.equals(REAL) || t.equals(DATE) || t.equals(TIME) || t.equals(TIMESTAMP);
}

try {
    value = Row.valueFromString(token, type);
} catch (PrestoException e) {
    if (e.getErrorCode().getCode() == StandardErrorCode.NOT_SUPPORTED.toErrorCode().getCode()) {
        return null; // or log and skip column
    }
    throw e;
}

When it happens

Trigger: Row.fromString / valueFromString with a schema column whose Type is not among the handled ones (BOOLEAN, BIGINT/integer family, DOUBLE, REAL, VARCHAR, VARBINARY, DATE/TIME/TIMESTAMP family, etc.), e.g. arrays, maps, rows, DECIMAL, JSON, hyperloglog.

Common situations: Connector schema includes ARRAY/MAP columns but the record format is plain delimited strings; newer Presto types added to the table schema that the deserializer predates.

Understand the failure class

Background: Presto NOT_SUPPORTED error: what "not supported" means and how to fix it — this error's family across 3 libraries.

Related errors

• NOT_SUPPORTED
• UNEXPECTED_ACCUMULO_ERROR
• NOT_SUPPORTED
• UNEXPECTED_ACCUMULO_ERROR
• ACCUMULO_TABLE_DNE

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/bdbb6dc2897f941f. Report an issue: GitHub.