How Does Stemma Discover Data Lineage?
When you execute SQL against your warehouse, the database captures the raw SQL and saves it in a historical format that includes the time the SQL command was executed and the user who executed it. Stemma reads these SQL logs and parses all of the commands that have been run, extracting several distinct pieces of information which appear in the Stemma UI on the Table Details page.
In the case of table and column lineage, any change to a table– via an insert, update or delete from another table– will create the appropriate table and column lineage tracking.
When lineage is created via
insert into table (select * from ...) statements, Stemma does not capture column level lineage.