Recently I was investigating a performance problem in a Spring Boot application using Spring Data and Postgres. A request to load a list of items took half a minute. I quickly realized that loading 1'600 items issued 20'000 database requests. After a quick optimization that brought down the number of queries to less than 200 the request still took 15 seconds. I decided that it was time to use a profiler and was surprised to see that almost all time was spent in methods of the Hibernate Validator.
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