How do you manage complexity in migration-heavy system changes?
I’m a full stack developer mainly working with Java Spring Boot and have 3 years experience just now.
Recently I worked on a ticket involving a few split PRs with around 2000 lines changed. This was my most complex backend work so far.
Because of how our system works, the data migration and sync logic needed to be reviewed and merged together, otherwise there would be data drift and inconsistencies between systems.
I got everything functional, but I struggled with the overall complexity and amount of edge cases.
It was more keeping track of all the workflow decisions, why I chose certain tradeoffs, rollout concerns, edge cases, and being able to clearly explain/document all of it during review.
By the end of it, I was just tired and when a more senior dev asked detailed questions, I struggled to explain on a meeting.
What do you do when changes start involving migrations, sync/dual-write logic, rollout sequencing, lots of edge cases, and interactions with different functions.
Do you have a process for documenting these decisions while doing the work?
Would appreciate any advice/tips from people who’ve worked on larger backend changes.