prestodb/presto · error · PrestoException

NOT_SUPPORTED

NOT_SUPPORTED

Error message

Unsupported column type: 

What it means

ClickHouseColumnHandle.toMappingDefaultJdbcHandle() converts a Presto column type into the default JDBC type handle used when falling back to the base JDBC connector. Types with no mapping (e.g. TIME as shown, or other exotic types) throw PrestoException NOT_SUPPORTED.

Source

Thrown at presto-clickhouse/src/main/java/com/facebook/presto/plugin/clickhouse/ClickHouseColumnHandle.java:236

        if (type.equals(DOUBLE)) {
            return new ClickHouseTypeHandle(Types.DOUBLE, Optional.of("double precision"), 32, 4, Optional.empty(), Optional.empty());
        }
        if (type instanceof CharType || type instanceof VarcharType) {
            return new ClickHouseTypeHandle(Types.VARCHAR, Optional.of("String"), 100, 0, Optional.empty(), Optional.empty());
        }
        if (type instanceof VarbinaryType) {
            return new ClickHouseTypeHandle(Types.VARCHAR, Optional.of("String"), 2000, 0, Optional.empty(), Optional.empty());
        }
        if (type == DATE) {
            return new ClickHouseTypeHandle(Types.DATE, Optional.of("date"), 8, 0, Optional.empty(), Optional.empty());
        }
        if (type == TIME) {
            return new ClickHouseTypeHandle(Types.TIME, Optional.of("time"), 4, 0, Optional.empty(), Optional.empty());
        }
        if (type == TIMESTAMP) {
            return new ClickHouseTypeHandle(Types.TIMESTAMP, Optional.of("timestamp"), 8, 0, Optional.empty(), Optional.empty());
        }
        throw new PrestoException(NOT_SUPPORTED, "Unsupported column type: " + type);
    }
}

View on GitHub (pinned to 55bb57d202)

Solutions

1. Alter the ClickHouse table column to a supported type (Date/DateTime/String/numeric)
2. Cast the column in your SELECT so it maps to a supported Presto type
3. Exclude the unsupported column from the query
4. Upgrade the plugin to a version that handles the type

Example fix

// before
SELECT my_time_col FROM ch.db.t;
// after
SELECT CAST(my_time_col AS TIMESTAMP) AS my_time_col FROM ch.db.t;

for (Column c : tableColumns) {
    if (c.getType().equals(TIME) || c.getType() instanceof TimeWithTimeZoneType) {
        throw new IllegalArgumentException("Column " + c.getName() + " type unsupported for ClickHouse reads: " + c.getType());
    }
}

boolean isClickHouseReadable(Type t) {
    return !(t.equals(TIME) || t.equals(TIMESTAMP) && isKnownUnsupported(t))
        || isSupportedClickHouseType(t);
}

try {
    return toMappingDefaultJdbcHandle(type);
} catch (PrestoException e) {
    if (e.getErrorCode().getCode() == NOT_SUPPORTED.toErrorCode().getCode()) {
        return Optional.empty(); // skip/Exclude this column
    }
    throw e;
}

When it happens

Trigger: Reading a ClickHouse table whose column maps to a Presto type the connector cannot translate to a default JDBC handle, typically during column handle conversion for reads when a ClickHouse-specific type handle is missing.

Common situations: Tables containing TIME-like columns; connector fallback paths triggered by unusual ClickHouse types; schema changed upstream after table creation.

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
• NOT_SUPPORTED
• NOT_SUPPORTED
• TABLE_NOT_FOUND
• NOT_SUPPORTED

AI-assisted analysis of prestodb/presto@55bb57d202 (2026-09-04). Data as JSON: /api/errors/ba416d65e56cc0c7. Report an issue: GitHub.