How long does it take for google play to update the app rankings?

So I have been observing my app ranking in a particular country and at the same time the number of downloads it is getting from that region. Yesterday and the day before my app got a huge number of downloads from this region (about 30 & 10 times that on a typical day respectively). But my app’s ranking has not changed at all in this region when I saw it today. Does google play has a delay in the rank changes or it is possible that this boost wasn’t enough to change my app’s rank at all? Thanks !!

Sometime few hours, mostly one day, sometime few days, it is up to Google.

It’s indexed every week.

As far as I can observe, the install count on Google Play is usually 1~2 days behind for my app. It actually took me 2 full days to see new installed count. I guess, I wasn’t sure was it total count or was it retained count. Retianed count was two shy of 50 and last night i saw 2 more users sign up.