The unforeseen challenge
Migrating MySQL to PostgreSQL was the hard part. Legacy data was inconsistent and free typed: invalid phone numbers and postal codes, mixed values in single fields, non standard quantities like "1 pail" or "6x2", missing or duplicate identifiers. We built a custom ETL and data cleaning layer plus an exception reporting system to track and fix every failed record. A production incident on the first deployment reshaped the migration strategy and made it far more robust.





