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Java

Thomas Nilsen
Thomas Nilsen
14,957 Points
Posted by Thomas Nilsen
Thomas Nilsen
14,957 Points

Rest API in Spring

The workshop was great.

However, I came across something that is important to be aware of.

If you make a call to /reviews, you get a whopping 22(!!) calls to the DB. This is completely unnecessary, and could easily lead to performance issues.

alt text

This is called the N+1 problem in hibernate

One fix for this, would be to annotate the Course table like so:

@Entity
@BatchSize(size = 10)
public class Course extends BaseEntity {

}

This would essentially reduce the number of queries to N / 10+1

After I add this and make a new request to /reviews, this is the result:

alt text

Down to 4 queries. Much better.