Cosmos: Allow users to pass in a QueryRequestOptions on a per-query basis

[roji]

Cosmos allows tweaking query execution in many ways via QueryRequestOptions; we could have a WithQueryRequestOptions() operator to allow the user to specify this.

Note that we already set PartitionKey and MaxItemCount.

[roji]

Consider the behavior when EF wants to set a request option and the user has passed in the object - does EF override the user option, etc.

For now, we'll consider this as a stretch goal for EF 10.

/cc @Pilchie

[Pilchie]

Is there a way to pass a request options to a lambda to allow the user to modify it? Of course, we have to decide on ordering and who gets the last word...

[roji]

@Pilchie not currently - that's what this issue tracks. I'm currently thinking of a per-query mechanism such as the following:

var stuff = context.Blogs
    .Where(b => b.Name.StartsWith("X"))
    .WithRequestOptions(new() { /* the stuff */ })
    .ToListAsync();

Does that seem ok?

[Pilchie]

Does that seem ok?

Basically I was thinking about something similar, but instead of having the user return a new instance, you could have the user supply a lambda that modifies an existing instance that EF had created. This lets the user have the last say. Your alternative works if you want EF to the last say though:

var stuff = context.Blogs
     .Where(b => b.Name.StartsWith("X"))
     .WithRequestOptions(existingOptions => { existingOptions.Option = newValue; } )
     .ToListAsync();

[roji]

@Pilchie makes sense - yeah, it depends on the who-wins question. We'll take all this into account when designing, thanks!