A pipeline you are afraid to re-run is a pipeline that will eventually corrupt data. This guide covers partition overwrite, MERGE upserts, dedup keys, watermarks and why exactly-once is a property you build, not a setting you enable.
DataTransfer-Regional-Bytes grew to 11,000 USD a month, behind only EC2 and RDS. Services spread across three zones talked to each other at random, and Kafka consumers read from leaders in other zones. Topology-aware routing and follower fetching cut it by 68 percent.
Our enrichment consumers rebalanced every few minutes, lag climbed past two million messages and some records were processed twice. A slow external API pushed batch processing past max.poll.interval.ms. How we proved it, fixed the poll loop and made rebalances cheap.