The length of clob type

Error message

The length of clob type {} is out of range, it will be converted to {}({})

What it means

When converting a string/CLOB-typed column back to DB2 DDL, if the declared length exceeds DB2's maximum CLOB size (MAX_CLOB_LENGTH = 2147483647 characters), the converter clamps it to the maximum and logs this warning, emitting CLOB(max). Otherwise DB2 DDL creation would fail with an oversized length.

Solutions

Cap the string column length to <= 2147483647 in the source schema
Accept the clamped CLOB(2147483647) and confirm data fits within the limit
If the text actually fits in VARCHAR, map to a VARCHAR(<=32672) to avoid CLOB overhead
Store oversized documents externally and sync only references

Example fix

// before (source schema)
StringType(length = 4294967295)
// after (clamped to DB2 max)
StringType(length = 2147483647) // CLOB(2147483647)

Defensive patterns

Strategy: validation

Validate before calling

// before write
long len = column.getColumnLength();
if (len > 2147483647L) {
    throw new IllegalArgumentException("CLOB length " + len + " exceeds DB2 max 2147483647 for column " + column.getName());
}

Type guard

boolean fitsDb2Clob(long length) {
    return length <= 2147483647L;
}

Prevention

Cap text column lengths at 2GB-1 for DB2 sinks
Use VARCHAR(<=32672) when content is small to avoid CLOB overhead
Avoid Long.MAX_VALUE as a stand-in for unknown string length

When it happens

Trigger: reconvert processes a StringType column whose getColumnLength() is greater than 2147483647, e.g. sources reporting LONGTEXT with 4GB lengths or unknown lengths mapped to Long.MAX_VALUE.

Common situations: Syncing MySQL LONGTEXT into DB2; connectors defaulting unknown string lengths to max long; schema definitions with huge hand-set lengths.

Understand the failure class

Background: "value must be between 0 and 1" / "out of range" / "must not be negative" errors: fixing range-validation failures across open-source libraries — this error's family across 42 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/62dff8f8ee798360. Report an issue: GitHub.

Appendix: source

Thrown at seatunnel-connectors-v2/connector-jdbc/src/main/java/org/apache/seatunnel/connectors/seatunnel/jdbc/internal/dialect/db2/DB2TypeConverter.java:373

            case STRING:
                if (column.getColumnLength() == null || column.getColumnLength() <= 0) {
                    builder.columnType(String.format("%s(%s)", DB2_VARCHAR, MAX_VARCHAR_LENGTH));
                    builder.dataType(DB2_VARCHAR);
                    builder.length(column.getColumnLength());
                } else if (column.getColumnLength() <= MAX_CHAR_LENGTH) {
                    builder.columnType(String.format("%s(%s)", DB2_CHAR, column.getColumnLength()));
                    builder.dataType(DB2_CHAR);
                    builder.length(column.getColumnLength());
                } else if (column.getColumnLength() <= MAX_VARCHAR_LENGTH) {
                    builder.columnType(
                            String.format("%s(%s)", DB2_VARCHAR, column.getColumnLength()));
                    builder.dataType(DB2_VARCHAR);
                    builder.length(column.getColumnLength());
                } else {
                    long length = column.getColumnLength();
                    if (length > MAX_CLOB_LENGTH) {
                        length = MAX_CLOB_LENGTH;
                        log.warn(
                                "The length of clob type {} is out of range, "
                                        + "it will be converted to {}({})",
                                column.getName(),
                                DB2_CLOB,
                                length);
                    }
                    builder.columnType(String.format("%s(%s)", DB2_CLOB, length));
                    builder.dataType(DB2_CLOB);
                    builder.length(length);
                }
                break;
            case DATE:
                builder.columnType(DB2_DATE);
                builder.dataType(DB2_DATE);
                break;
            case TIME:
                builder.columnType(DB2_TIME);
                builder.dataType(DB2_TIME);

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