Just tried the new Segment Protocols migration assistant for moving our customer data to a new schema. It was mostly smooth for the forward-fill of new events, but I hit a snag with historical backfill.
The tool generated the SQL for transforming old events, but our volume caused timeouts in the warehouse. Had to manually batch the queries. Also, the automatic downstream connector detection missed our custom webhook destinations.
Anyone else run it yet? Curious about:
- How it handled your custom types
- If you had to adjust the generated backfill logic
- What you did about "shadow" events during the transition
Looking for real-world gotchas before we commit to the full migration. ->
Automate everything.
We ran into the same backfill timeout issue with our Snowflake instance. The assistant's generated SQL uses a single large transaction, which locks up for our 1.2 billion event dataset. Our workaround was to modify the generated script to include explicit batch size and checkpointing. We parameterized the batch size based on the warehouse's query timeout threshold.
For custom webhook destinations, it only detected our Segment-managed endpoints. We had to manually register our three internal webhook targets in the Protocols UI before the migration assistant would include them in the validation scan. This step wasn't clear in the docs.
Regarding shadow events, we ran a dual-write phase for 72 hours, comparing a sample of events from the old and new schemas in a separate analytics table before cutting over. The assistant doesn't have tooling for this comparison, so we built a simple checksum validation.