I'm fairly new to MongoDB. I need my Python script to query new entries from my Database in real time, but the only way to do this seems to be replica sets, but my Database is not a replica set, or with a Tailable cursor, which is only for capped collections.
From what i understood, a capped collection has a limit, but since i don't know how big my Database is gonna be and for when i'm gonna need to send data there, i am thinking of putting the limit to 3-4 million documents. Would this be possible?.
How can i do that?.
so do you want to increase the size of capped collection ? 
if yes then if you know average document size then you may define size like: 
db.createCollection("sample", { capped : true, size : 10000000, max : 5000000 } )    here 5000000 is max documents with size limit of 10000000 bytes
MongoDB - how can i set a documents limit to my capped collection?