druid/docs/development/extensions-contrib/delta-lake.md

id	title
delta-lake	Delta Lake extension

Delta Lake extension

Delta Lake is an open source storage framework that enables building a Lakehouse architecture with various compute engines. DeltaLakeInputSource lets you ingest data stored in a Delta Lake table into Apache Druid. To use the Delta Lake extension, add the druid-deltalake-extensions to the list of loaded extensions. See Loading extensions for more information.

The Delta input source reads the configured Delta Lake table and extracts all the underlying delta files in the table's latest snapshot. These Delta Lake files are versioned Parquet files.

Version support

The Delta Lake extension uses the Delta Kernel introduced in Delta Lake 3.0.0, which is compatible with Apache Spark 3.5.x. Older versions are unsupported, so consider upgrading to Delta Lake 3.0.x or higher to use this extension.

Downloading Delta Lake extension

To download druid-deltalake-extensions, run the following command after replacing <VERSION> with the desired Druid version:

java \
  -cp "lib/*" \
  -Ddruid.extensions.directory="extensions" \
  -Ddruid.extensions.hadoopDependenciesDir="hadoop-dependencies" \
  org.apache.druid.cli.Main tools pull-deps \
  --no-default-hadoop \
  -c "org.apache.druid.extensions.contrib:druid-deltalake-extensions:<VERSION>"

See Loading community extensions for more information.

Known limitations

• This extension relies on the Delta Kernel API and can only read from the latest Delta table snapshot.
• Column filtering isn't supported. The extension reads all columns in the configured table.