Parse.com：“ createdAt”的降序是否可扩展？

Question

I am trying to get the most recent top 10 items from a Table in Parse. Let's say there are more than 1M items in that Table, will descending order on "createdAt" Scalable?

Basically, you need to descending order on "createdAt" and get the top 10 items. Will this code run slowly for large amount of items (from 100K to a few Million)?

So Far I am very uncertain about parse.com's performance and scalability for ordering large amount of items. I know for large amount of items, their ordering function will be slow. I am just not sure about the ordering on "createdAt".

Thanks

Answer 1

Parse uses mongodb, and it very likely indexes createdAt by default. If not, it very likely will index createdAt upon noticing your app's call pattern . Speed for top N (where N<100) should be very quick, relatively independently of table size.

Note that this is a much weaker statement than "parse is the best choice for 1M row tables".