Kafka Lag Looked Fine. One Partition Was Not.
Learn how partition-level Kafka lag, slow consumer paths, hot keys, and worker handoffs reveal delays that total lag dashboards can hide from teams.
PostgreSQL Was Not Slow. Our Index Was Useless.
Learn why a PostgreSQL index can still be useless and how composite indexes, EXPLAIN ANALYZE, and query patterns improve reporting speed.
Postman Timed Out, but Kafka Was Still Receiving Jobs
Postman timed out while Spring Boot kept sending Kafka jobs. See how SSE progress, idempotency, and async boundaries fixed it.
Postman Timed Out, but Kafka Was Still Receiving Jobs Read More »
Spring Boot Did Not Leak Memory. Redis Had No Exit
Redis memory kept growing in Spring Boot because cache keys had no TTL, maxmemory, eviction policy, or namespace-level monitoring.
Spring Boot Did Not Leak Memory. Redis Had No Exit Read More »
When Files.move() Deleted the Wrong Java File
A production-style Java file handling lesson about Files.move(), reused filenames, race conditions, and safer file lifecycle design.