Question

I have a MVC application which returns 2 types of Json responses from 2 controller methods; AnyRemindersExist() and GetAllUserReminders(). The first returns a boolean, 2nd returns an array, both wrapped as Json.

I have a JavaScript timer checking for calendar reminders against a user. It makes the first call (AnyRemindersExist) to check whether reminders exist and whether the client should then make the 2nd call.

For example, if the result of the Json response is false from the Any() query, it doesn’t then make the 2nd controller action which makes a LINQ select call. If there are reminders that exist, it then goes further and then requests them (making use of the LINQ SELECT).

Imagine a system ramped up where 100-1000s users use the system and on the client, every 30-60 seconds a request comes in to load in the reminders. Does this Any() call help in anyway in reducing load on the server?

Answer 1

I would say that it depends on how the underlying queries are translated. If the any call is translated into an indexed lookup when the select (perhaps due to a join to get related data) must do some sort of table scan, then it will save some work in the case when there are no reminders to be found. It will cause a little extra work when there are reminders. It might be useful if the majority of the calls don’t result in any results.

In the general case, though, I would just select the data and only try to optimize IF that turns out to not be fast enough. The conditions under which it will actually save effort on the server are pretty narrow and might only apply if you hand-craft the SQL rather than depend on your ORM.