01Discovery and metadata profiling
Catalogue the current estate from the information schema, DDL, query logs and job schedules: tables, volumes, refresh frequencies, objects nothing reads and the handful that carry the business. Profile the data itself for types, null rates, key uniqueness and history depth, so the target design reflects what is there rather than what the documentation claims.
02Dependency and impact analysis
Trace what reads each object — views, stored procedures, scheduled jobs, extracts, semantic models and dashboards — and flag hardcoded rules, cross-database joins and platform-specific SQL that will not survive the move. This is the analysis that decides whether a migration is a planned project or a sequence of surprises.
03Source-to-target mapping
A written mapping per object: source, target table and layer, data types, transformation rules, keys, grain, historical scope and the check that proves it landed correctly. It is the document both sides sign off and the basis for every test that follows.
04Target design: raw, staging, curated and reporting layers
Design Snowflake, BigQuery or Redshift with separated layers: raw as it arrived, staging conformed, curated facts and dimensions, and reporting shapes that BI tools read. Partitioning, clustering and incremental loads are chosen against real query patterns, which is where the 60–75% reductions in query scan size on past engagements came from.
05Validation and reconciliation
Automated comparison between old and new at each pipeline stage: record counts, date coverage, nulls, duplicates, control totals and metric-level comparison of the figures people actually report. Differences are explained rather than rounded away — several times they have revealed a defect in the legacy logic. This work has cut manual reconciliation effort by more than 70% on past migrations.
06Dashboard and semantic-model impact
Repoint Power BI, Tableau, Looker Studio or Analysis Services models at the new layers, or rebuild them where the old model was itself the problem. Report-level differences are reconciled visual by visual before a dashboard is called migrated.
07Cutover, parallel run and handover
Plan the sequence: what runs in parallel and for how long, the freeze window, who signs off each domain, what is decommissioned when, and how to roll back. Handover includes the mappings, ER diagrams, validation results, schedules, ownership and operating runbooks.