I don't quite follow the question here but to clarify one thing: Kùzu is currently integrating Arrow not as a core storage structure but as a file format from which we can ingest data. We are writing Kùzu's entire storage, so it's our own design. It has three components: Vanilla columns for node properties, columnar compressed sparse row (https://tinyurl.com/2r2s4wpe) join indices and relationship properties, and a hash index for primary keys of node records. We don't use Arrow to store db files.

For serializability: yes, we support serializable transactions. So when you insert, delete or update node, rel records, you get all or nothing behavior (e.g., if you rollback none of your updates will be visible).

That said, supporting ACID transactions is a compeletely separate design decision in DBMSs, so our (or other systems') mechanisms to support transactions (for example whether it's based on write ahead logging or not) and storage designs are generally mutually exclusive decisions.