EF.CompileQuery The LINQ expression could not be translated.

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EF.CompileQuery((DbContext context) => context.Set<T>().AsNoTracking().Where(filter).ToList())(this); Message=The LINQ expression ‘DbSet<LhUser>() .Where(l => l.Id == 1) .ToList()’ could not be translated. Either rewrite the query in a form that can be translated, or switch to client evaluation explicitly by inserting a call to ‘AsEnumerable’, ‘AsAsyncEnumerable’, ‘ToList’, or ‘ToListAsync’. I use the EF core 5.0.7，but the sdks is net core 3.1, Remember:

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BlogContext

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[smitpatel]

Not opposing though

• EF.CompileQuery needs a redesign. There is tracking issue for it.
• The tracking issue is blocked because it needs to prove that it is useful perf wise too. We added it because EF6 had it and certainly we have customers out there using it. But does it make sense to write new queries using compiled query if perf difference is negligible. People porting over old EF6 queries, we should try to make that work.
• Our fancy exception message (though I guess we should change it to point to the obvious) contains the query tree in which last method call/operator is the one which caused translation to fail. In this case it is ToList 😉
• This would be different infra than currently what we have for translation failures.
  • ToList in normal queries work in the sense that we never see top level ToList - that is how IQueryable works
  • Any ToList we see are in subquery so we are materializing collection for it and we process it correctly
  • That means we need a special way to find out that it is CompiledQuery, a hook which we currently don’t have. We treat expression tree for any query same once it enters query compiler.

[ajcvickers]

Note from triage: added a note to #14551 to consider when re-visiting compiled query API.