I just rediscovered this Sway from last summer. Another custom data ETL job with almost 800,000 rows across the main objects.
The client was in the schools and school district performance consulting business. And they wanted their Salesforce org to incorporate the voluminous student and school performance statistics that Albany churns out each year so that as a school’s performance went down, before censure and closure a school is warned. And those signals are in the data, so in Salesforce, they would know which schools and districts would be receptive.
A lot of records any way you look at it.
For another large data migration, see Blue Print Wealth.