Migrating a Massive Legacy Database

Lessons learned at SeatGeek when migrating a massive legacy MySQL database to Postgres

Transcript

1. MIGRATING A MASSIVE LEGACY DATABASE
4. AGENDA ▸ Moving offices ▸ The ecology of large systems ▸ On keeping track of what you know ▸ Profiting from the unexpected ▸ The perceived value of tests ▸ Aligning goals at the company level ▸ Profiting from the unexpected pt. 2 ▸ Rehearsals ▸ Announcing your intentions
5. HOW DO YOU MOVE OFFICES?
6. LESSON 1: LARGE TECHNICAL PROJECTS ARE DIFFICULT BECAUSE THEY ARE SOCIAL PROBLEMS
8. LESSON 2: LARGE SYSTEMS ARE ECOSYSTEMS
10. LESSON 3: KEEP YOUR FACTS CENTRALIZED
11. CENTRALIZED FACTS FROM A SINGLE DHALL REPRESENTATION WE… ▸ Created usage diagrams ▸ Sent automated pull requests to other teams ▸ Calculated progress reports ▸ Tracked tables that were migrated to other databases already ▸ Created terraform configuration for DMS
12. LESSON 4: EXPLOIT THE UNEXPECTED
14. LESSON 5: TESTS WILL SLOW YOU DOWN
15. ‣ Ordering issues ‣ Queries using GROUP BY ‣ Queries relying on case insensitivity ‣ Type mismatches WASTE ?
16. LESSON 6: LONG TERM PLATFORM GOALS DON’T ALWAYS ALIGN WITH SHORT TERM BUSINESS GOALS
18. LESSON 7: NEVER LET A CRISIS GO TO WASTE
21. LESSON 8: PRACTICE, PRACTICE, PRACTICE
22. LESSON 9: COMMUNICATE YOUR INTENT