Report Migration Inventory
The enumerated list of every report, extract and downstream consumer of the legacy warehouse, with usage evidence, which is what makes the migration finite.
The technical work of moving a warehouse is bounded. The unbounded part is the thousands of reports, extracts, spreadsheets and applications pointed at it, most of which nobody can list from memory.
The inventory has to be built from evidence rather than from asking. Query logs give what actually ran, how often, and by which account. That immediately splits the estate: typically a third of reports have not been executed in a year, a small number account for most of the usage, and a long tail runs monthly or annually and will be missed entirely by a sampling exercise.
The retirement conversation is the highest-value part of the whole migration. Every report not migrated is work avoided, and the evidence — "this has not been run since 2024" — makes the conversation short. Migrating everything because nobody was willing to decide is how a two-year programme happens.
Two things the log does not show: reports scheduled to run but whose output nobody opens, and consumers reading tables directly rather than through the reporting layer. The first needs the delivery system's own telemetry; the second needs the access logs, and it is where the surprises are.