`compaction.write_parquet_max_row_group_rows` must be…

Error message

`compaction.write_parquet_max_row_group_rows` must be greater than 0

What it means

The altered Iceberg sink config requires `compaction.write_parquet_max_row_group_rows` to be positive. Zero rows per Parquet row group is invalid (no rows could ever be written per group), so validation rejects it.

Solutions

Set the property to a positive integer, e.g. `1000000` (1M rows per row group).
Remove the property to use the sink's default row group size.
If tuning memory, lower bytes (`compaction.write_parquet_max_row_group_bytes`) instead of zeroing rows.

Example fix

-- before
ALTER SINK s SET ('compaction.write_parquet_max_row_group_rows'='0');
-- after
ALTER SINK s SET ('compaction.write_parquet_max_row_group_rows'='1000000');

Defensive patterns

Strategy: validation

Validate before calling

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

Prevention

Never zero any row-group knob; lower values only if memory constrained.
Set rows and bytes knobs together consistently.

When it happens

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

Common situations: Copy-pasted defaults that were zeroed; confusion with parquet writer tuning knobs; templating that substitutes 0 when a variable is unset.

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/5a0877bedfb77e78. Report an issue: GitHub.

Appendix: source

Thrown at src/connector/src/sink/iceberg/mod.rs:344

        {
            bail!(
                "`compaction.max_snapshots_num` must be greater than 0, got: {}",
                max_snapshots
            );
        }

        // 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",

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