Open table formats like Delta Lake, Apache Iceberg, and Apache Hudi extend file formats such as Parquet by adding a metadata layer that enables ACID transactions, advanced data skipping, time travel, schema enforcement and evolution, and full CRUD operations. These capabilities make them more reliable and performant than traditional data lakes built on raw Parquet or CSV files. Interoperability projects such as Delta Lake UniForm, Apache XTable, and Unity Catalog are reducing the friction of using multiple table formats together, letting teams write in one format and read in another. Converting from an open table format back to plain Parquet is possible but generally discouraged unless versioning and transaction features are no longer needed.
Table of contents
What is an open table format?Why should I use an open table format?Can I use different open table formats together?Can I convert an open table format to a file format like Parquet?When should I use an open table format?Questions this post answers
What is the difference between an open table format like Delta Lake and just storing data in Parquet files?
Open table formats add a metadata layer on top of file formats like Parquet to enable ACID transactions, advanced data skipping, time travel, schema enforcement and evolution, and full CRUD operations. Regular Parquet files are immutable and can only be overwritten entirely, while open table formats let you perform logical partial updates, like row-level deletes, by updating pointers in a transaction log instead of rewriting data. daily.dev surfaces practical comparisons for teams deciding between raw file storage and open table formats.
Can I use Delta Lake and Apache Iceberg together in the same data pipeline?
Yes, tools like Delta Lake UniForm and Apache XTable are designed to unify workflows across open table formats. For example, you can write your ETL workload in Delta Lake and then use UniForm to expose that data as Iceberg tables for downstream BI and analytics systems. Unity Catalog similarly lets you store and access tabular data across both Delta Lake and Iceberg formats. Track interoperability tooling like UniForm and Unity Catalog on daily.dev as multi-format data stacks evolve.
How do I convert a Delta Lake table back into plain Parquet files?
To convert a Delta table into a Parquet data lake with Hive-style partitions, first vacuum any stale files, then remove the transaction log directory. This is generally discouraged from a performance standpoint since Delta Lake is almost always faster and more reliable; only do it if you no longer need versioning or transaction management features. daily.dev helps engineers weigh trade-offs like this before dropping Delta Lake features for plain Parquet.