`compaction.write_parquet_max_row_group_bytes` must be…

Error message

`compaction.write_parquet_max_row_group_bytes` must be greater than 0

What it means

Guard in validate_alter_config: `compaction.write_parquet_max_row_group_bytes` was set to 0, which is invalid because a Parquet row group cannot be empty. Fires when ALTER SINK applies new connector settings to an existing Iceberg sink.

Solutions

Set the property to a positive byte count, e.g. `134217728` (128 MiB).
Remove the property to use the default row group byte size.
Tune both rows and bytes knobs together so neither is zero.

Example fix

-- before
ALTER SINK s SET ('compaction.write_parquet_max_row_group_bytes'='0');
-- after
ALTER SINK s SET ('compaction.write_parquet_max_row_group_bytes'='134217728');

Defensive patterns

Strategy: validation

Validate before calling

fn valid_row_group_bytes(cfg: &std::collections::BTreeMap<String, String>) -> Result<(), String> {
    if let Some(s) = cfg.get("compaction.write_parquet_max_row_group_bytes") {
        if s.parse::<u64>().unwrap_or(0) == 0 {
            return Err("compaction.write_parquet_max_row_group_bytes must be > 0".into());
        }
    }
    Ok(())
}

Prevention

Specify byte sizes as plain integers (bytes), e.g. 134217728 for 128 MiB.
Double-check unit conversion in any config generator.

When it happens

Trigger: `ALTER SINK ... SET` with `compaction.write_parquet_max_row_group_bytes = '0'`.

Common situations: Hand-computed byte values that ended up 0; trying to disable byte-based row group rolling; unit mistakes (expecting bytes but writing 0).

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 risingwavelabs/risingwave@6469eb736d (2026-09-11). Data as JSON: /api/errors/f06e1685094db2f2. Report an issue: GitHub.

Appendix: source

Thrown at src/connector/src/sink/iceberg/mod.rs:351

        // Validate target file size
        if let Some(target_file_size_mb) = iceberg_config.target_file_size_mb
            && target_file_size_mb == 0
        {
            bail!("`compaction.target_file_size_mb` must be greater than 0");
        }

        // Validate parquet max row group rows
        if let Some(max_row_group_rows) = iceberg_config.write_parquet_max_row_group_rows
            && max_row_group_rows == 0
        {
            bail!("`compaction.write_parquet_max_row_group_rows` must be greater than 0");
        }

        // Validate parquet max row group bytes
        if let Some(max_row_group_bytes) = iceberg_config.write_parquet_max_row_group_bytes
            && max_row_group_bytes == 0
        {
            bail!("`compaction.write_parquet_max_row_group_bytes` must be greater than 0");
        }

        // Validate parquet compression codec
        if let Some(ref compression) = iceberg_config.write_parquet_compression {
            let valid_codecs = [
                "uncompressed",
                "snappy",
                "gzip",
                "lzo",
                "brotli",
                "lz4",
                "zstd",
            ];
            if !valid_codecs.contains(&compression.to_lowercase().as_str()) {
                bail!(
                    "`compaction.write_parquet_compression` must be one of {:?}, got: {}",
                    valid_codecs,
                    compression

View on GitHub (pinned to 6469eb736d)