如何在休眠/JPA应用中检测N+1问题
原标题：How to detect N+1 problems in a Hibernate/JPA application
Given that N+1 has been the most pernicious problem with Hibernate/JPA applications for about 20 years, I was hoping there s a way of detecting it (before it s too late). Something like the following:
Install "N+1 detector" dependency
Run the test suite
The N+1 detector reports occurrences (or likely occurrences) of N+1 that were encountered during the test suite execution
I m not sure how exactly this mythical N+1 detector would work, but if you could proxy the database queries and notice that the same query is being executed multiple times in quick succession, then that s a likely case of N+1.
However, I haven t actually found anything like this, does it exist? Is there any automated, or semi-automated way to detecting N+1?
I m not sure how relevant this is, but in my specific case I m using Spring Boot 3.X with Spring Data JPA.
最佳回答
If you are looking for automatised tools for detect N+1 then with Digma, you can easily detect such queries even when working with complex codebases.
If you are looking for more details I highly recommend to you got through this article. https://digma.ai/n1-query-problem-and-how-to-detect-it/
问题回答
The N+1 problem is a common performance issue that occurs when fetching data from a database using an ORM framework like Hibernate or JPA.
There are several ways to detect and prevent the N+1 problem in Spring Boot applications using Spring Data JPA.
Here are some approaches:
Using EntityGraph annotations to specify which associations should be fetched eagerly or lazily.Reference link
Using AppMap plugin for IntelliJ to visualize the queries executed by the ORM and identify the N+1 queries.Reference link
Using DataLoader pattern to batch and cache the queries for related entities.Reference link
Using JOIN FETCH or @Fetch(FetchMode.JOIN) to fetch the main entities and their associations in one query.Reference link
Using spring-hibernate-query-utils library to auto-detect the N+1 queries in your application.Reference link
I hope this helps you solve your problem.?
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