apache/seatunnel · error · RuntimeException

Cannot convert timestamp: , type:

Error message

Cannot convert timestamp: , type: 

What it means

Iceberg RowConverter throws this RuntimeException when a non-UTC timestamp (Iceberg TimestampType without UTC adjustment) value cannot be converted to LocalDateTime. convertLocalDateTime accepts String, LocalDateTime, OffsetDateTime, and Date; anything else is rejected with the value and its class in the message.

Source

Thrown at seatunnel-connectors-v2/connector-iceberg/src/main/java/org/apache/seatunnel/connectors/seatunnel/iceberg/data/RowConverter.java:468

            return LocalDateTime.parse(tsStr, DateTimeFormatter.ISO_LOCAL_DATE_TIME)
                    .atOffset(ZoneOffset.UTC);
        }
    }

    private LocalDateTime convertLocalDateTime(Object value) {
        if (value instanceof Number) {
            long millis = ((Number) value).longValue();
            return DateTimeUtil.timestampFromMicros(millis * 1000);
        } else if (value instanceof String) {
            return parseLocalDateTime((String) value);
        } else if (value instanceof LocalDateTime) {
            return (LocalDateTime) value;
        } else if (value instanceof OffsetDateTime) {
            return ((OffsetDateTime) value).toLocalDateTime();
        } else if (value instanceof Date) {
            return DateTimeUtil.timestampFromMicros(((Date) value).getTime() * 1000);
        }
        throw new RuntimeException(
                "Cannot convert timestamp: " + value + ", type: " + value.getClass());
    }

    private LocalDateTime parseLocalDateTime(String str) {
        String tsStr = ensureTimestampFormat(str);
        try {
            return LocalDateTime.parse(tsStr, DateTimeFormatter.ISO_LOCAL_DATE_TIME);
        } catch (DateTimeParseException e) {
            return OFFSET_TS_FMT.parse(tsStr, OffsetDateTime::from).toLocalDateTime();
        }
    }

    private String ensureTimestampFormat(String str) {
        String result = str;
        if (result.charAt(10) == ' ') {
            result = result.substring(0, 10) + 'T' + result.substring(11);
        }
        if (result.length() > 22 && result.charAt(19) == '+' && result.charAt(22) == ':') {

View on GitHub (pinned to cf67b549a7)

Solutions

1. Convert the value to LocalDateTime or java.util.Date before the sink.
2. Add a transform CAST(column, TIMESTAMP) to deliver a supported type.
3. For Instants: LocalDateTime.ofInstant(instant, ZoneId.systemDefault()).
4. Configure the source so timestamps map to SeaTunnel TimestampType (LocalDateTime-backed).

Example fix

// before
writer.write(idx, Instant.now()); // Instant not accepted
// after
writer.write(idx, LocalDateTime.ofInstant(Instant.now(), ZoneId.systemDefault())); // LocalDateTime accepted

if (!(v instanceof LocalDateTime) && !(v instanceof OffsetDateTime) && !(v instanceof java.util.Date) && !(v instanceof String)) throw new IllegalArgumentException("timestamp column must be LocalDateTime/OffsetDateTime/Date/String, got " + (v == null ? "null" : v.getClass().getName()));

boolean isTimestampConvertible(Object v) { return v instanceof LocalDateTime || v instanceof OffsetDateTime || v instanceof java.util.Date || v instanceof String; }

try { sink.write(row); } catch (RuntimeException e) { if (e.getMessage() != null && e.getMessage().startsWith("Cannot convert timestamp")) { /* convert Instant/ZonedDateTime or DLQ */ } else throw e; }

When it happens

Trigger: convertLocalDateTime receives an unsupported object (e.g. Long, ZonedDateTime, Instant) while converting a field for a plain (non-timestamptz) Iceberg timestamp column via convertTimestampValue.

Common situations: Sources emitting Instant/ZonedDateTime for timestamp columns; epoch-seconds Long values from JSON/CDC sources; schema changes altered the column type upstream.

Understand the failure class

Background: Type mismatch errors: IllegalArgumentException, TypeError and type guards across 150 open-source libraries — this error's family across 150 libraries.

Related errors

• Cannot convert to BigDecimal:
• Cannot convert to boolean:
• Cannot convert to UUID:
• Cannot convert to binary:
• Cannot convert date:

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/da7fcad569d4d181. Report an issue: GitHub.