Function select_codec

nodedb-columnar/src/writer/segment_writer.rs:189–227

Select the best codec for a column type using nodedb-codec's auto-detection. Always returns a `ResolvedColumnCodec` — `Auto` is consumed here and never forwarded downstream.

(col_type: &ColumnType)

/// Always returns a `ResolvedColumnCodec` — `Auto` is consumed here and
/// never forwarded downstream.
fn select_codec(col_type: &ColumnType) -> ResolvedColumnCodec {
    let hint = match col_type {
        ColumnType::Int64 => ColumnTypeHint::Int64,
        ColumnType::Float64 => ColumnTypeHint::Float64,
        ColumnType::Timestamp | ColumnType::Timestamptz | ColumnType::SystemTimestamp => {
            ColumnTypeHint::Timestamp
        }
        ColumnType::String | ColumnType::Geometry | ColumnType::Regex => ColumnTypeHint::String,
        ColumnType::Bool
        | ColumnType::Bytes
        | ColumnType::Decimal { .. }
        | ColumnType::Uuid
        | ColumnType::Ulid => {
            return ResolvedColumnCodec::Lz4;
        }
        ColumnType::Json
        | ColumnType::Array
        | ColumnType::Set
        | ColumnType::Range
        | ColumnType::Record => {
            return ResolvedColumnCodec::Lz4;
        }
        ColumnType::Duration => ColumnTypeHint::Int64, // i64 microseconds
        ColumnType::Vector(_) => {
            return ResolvedColumnCodec::Lz4;
        }
        // ColumnType is #[non_exhaustive]; unknown types default to Lz4
        // general-purpose compression until a dedicated codec is registered.
        _ => {
            return ResolvedColumnCodec::Lz4;
        }
    };
    // detect_codec resolves Auto via the type hint and always returns a
    // concrete codec. Map any unexpected Auto back to a safe default
    // (Lz4) rather than panicking in library code.
    nodedb_codec::detect_codec(ColumnCodec::Auto, hint)
        .try_resolve()
        .unwrap_or(ResolvedColumnCodec::Lz4)
}

#[cfg(test)]
mod tests {