I was reading BigQuery the Definitive Guide last week and I was surprised to learn that BigQuery is actually immutable at its core even when using DML statements.

This is surfaced in the query language and you can query the table as it existed in the past using the syntax:

  SELECT * FROM
    table_name
  FOR SYSTEM TIME AS OF
    TIMESTAMP_ADD(CURRENT_TIMESTAMP(), INTERVAL -5 DAY)

The tables get rewritten periodically squashing this change history so you can only access states for the past week.