Performance problems explained from real failures
2 posts. All topics
A slow system rarely has one obvious cause. A page can be slow because of a query, a full pool of connections, a pause for memory cleanup, or a downstream service that is answering slowly.
The posts below start from a symptom and teach you to measure before changing anything. Each one shows how to confirm the cause, then compares the fixes and what each costs.
The goal is a habit: find what is actually waiting, fix that, and check that the numbers moved.
Posts on Performance
-
10 min read
HikariPool-1 Connection is not available: pool exhausted
Why a Java app hangs with Connection is not available errors under load, how leaked or hoarded connections cause it, and how to find and fix it.
-
15 min read
N+1 query problem in Hibernate and JPA: find it and fix it
Why a Hibernate or JPA page that is fast in development takes 10 seconds in production, how lazy loading hides hundreds of queries, and how to fix it.