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EF Core - Query splitting

In EF Core when fetching multiple entities in one request it can result in a cartesian product as the same data is loaded multiple times which negatively impacts performance.

An example is when I try to load a list of Customers with their ordered products:

The resulting query causes a cartesian product as the customer data is duplicated for every ordered product in the result set. EF Core will generate a warning in this case as it detects that the query will load multiple collections.

I talked before about the AsSplitQuery method to solve this. It allows Entity Framework to split each related entity into a query on each table:

However you can also enable query splitting globally in EF Core and use it as the default. Therefore update your DbContext configuration:

More information

EF Core–AsSplitQuery() (bartwullems.blogspot.com)

Single vs. Split Queries - EF Core | Microsoft Learn

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