Why teams end up with both formats

Delta Lake and Apache Iceberg solve similar table-management problems with different metadata models and ecosystems. Mergers, platform changes, and team preferences often leave both formats in the same data estate.

The comparison is covered in Delta Lake vs Iceberg. The operational question is what happens after the choice: do you now need a separate engine, catalog path, and maintenance workflow for each format?

UniForm helps readers cross the boundary

Delta UniForm asynchronously generates Iceberg metadata for a Delta table, allowing compatible Iceberg clients to read the Delta-managed data. It is useful interoperability, but it does not turn every engine into a native writer for both source formats.

That distinction matters. Interoperability metadata helps a reader consume a table. Native format support lets an engine create, mutate, maintain, and time-travel tables that are actually managed as either Delta or Iceberg.

The one-engine model

DeltaForge implements both table protocols behind one PostgreSQL-flavored SQL surface:

  • Create and register Delta Lake or Apache Iceberg tables.
  • Run INSERT, UPDATE, DELETE, and MERGE.
  • Query historical table versions.
  • Connect BI and application clients through ODBC or ADBC.

The engine is commercial and self-hosted. It does not convert every table into a proprietary storage format, and it does not require Spark or a JVM.

What stays separate

One engine does not mean one metadata model. Delta tables still commit to _delta_log. Iceberg tables still use Iceberg metadata, manifests, and snapshots as defined by the Apache Iceberg specification.

That separation is a feature. Each table remains readable by its wider ecosystem instead of becoming an engine-specific copy.

When this architecture helps

  • You acquired or inherited tables in both formats.
  • Different teams standardize on different formats.
  • You want one BI endpoint across the estate.
  • You need full DML without running separate Spark and Trino environments.

FAQ

Does one engine force a format migration?

No. A Delta table can remain Delta and an Iceberg table can remain Iceberg.

Can both formats use the same SQL syntax?

For common reads and DML, yes. Format-specific capabilities can still differ because the underlying protocols differ.

Where can I see the write paths?

See the worked guides for Delta Lake DML and Iceberg DML.

Run it yourself

Install DeltaForge and register one table from each format. Start with the install guide or get a Community license from the DeltaForge console.