Entity Framework Core 5.0 Warning limiting operator ('Skip'/'Take') without an 'OrderBy' operator

Question

I am writing a .net Core 3.1 application and have recently updated it to Entity Framework Core 5.0. Running the application has since started showing warnings as follows:

The query uses a row limiting operator ('Skip'/'Take') without an 'OrderBy' operator. This may lead to unpredictable results.

I have reviewed every instance of my code that would use .Skip or .Take or both and they all have a OrderBy clause.

My question is, are there any flags I can set with

DbContextOptiosnBuilder() .ConfigureWarnings(w => w.Throw(RelationalEventId.???))

to help determine where these .Skip and .Take queries are being ran or any way to trigger a stack trace with this warning to narrow down the cause.

Alternatively, how can one go about silencing this warning from the console?

Answer 1

In fact, you get this warning EVEN if you use a FirstOrDefault (or SingleOrDefault) on a primary key selection i.e.

context.dbsetXXX.SingleOrDefaultAsync(xxx => xxx.ID == id);

It seems to be due in how this query in badly mapped in T-SQL - using a TAKE(1) statement. So for now I would just Ignore the warning ( using .Ignore(CoreEventId.RowLimitingOperationWithoutOrderByWarning) ...)

Answer 2

The EventId value you are looking for is CoreEventId.RowLimitingOperationWithoutOrderByWarning.

A query uses a row limiting operation (Skip/Take) without OrderBy which may lead to unpredictable results.

This event is in the DbLoggerCategory.Query category.

As usual, the default action is Log, and you can turn it to error

.Throw(CoreEventId.RowLimitingOperationWithoutOrderByWarning)

or suppress it

.Ignore(CoreEventId.RowLimitingOperationWithoutOrderByWarning)