Frequently asked questions (FAQ)
What is Delta Lake?
Delta Lake is an open source storage layer that brings reliability to data lakes. Delta Lake provides ACID transactions, scalable metadata handling, and unifies streaming and batch data processing. Delta Lake runs on top of your existing data lake and is fully compatible with Apache Spark APIs.
What format does Delta Lake use to store data?
Delta Lake uses versioned Parquet files to store your data in your cloud storage. Apart from the versions, Delta Lake also stores a transaction log to keep track of all the commits made to the table or blob store directory to provide ACID transactions.
How can I read and write data with Delta Lake?
You can use your favorite Apache Spark APIs to read and write data with Delta Lake. See Read a table and Write to a table.
Where does Delta Lake store the data?
When writing data, you can specify the location in your cloud storage. Delta Lake stores the data in that location in Parquet format.
Can I stream data directly into and from Delta tables?
Yes, you can use Structured Streaming to directly write data into Delta tables and read from Delta tables. See Stream data into Delta tables and Stream data from Delta tables.
Does Delta Lake support writes or reads using the Spark Streaming DStream API?
Delta does not support the DStream API. We recommend Table streaming reads and writes.