Q:

Is it better to use a 128-bit long (uuid) or a 7-bit long (shortid) unique ID generator in Node? 

I'm currently using uuid npm package to generate unique IDs for the elements of my graph database in my node.js app.  
It generates RFC-compliant 128-bit long IDs, like 
6e228580-1cb5-11e8-8271-891867c15336

I'm currently thinking to shift to shortid npm package, which does a similar job but generates 7-bit long IDs:
PPBqWA9

My database requests are already long and I want to shorten them, so I'm considering the switch from uuid to shortid. 
However, the question: I understand that the 128-bit long compliant UUID generator guarantees that it's going to be unique.  What about the 7-bit one?  I understand it can provide about 78364164096 unique possibilities which is not bad, but I already have about 50M unique objects in my DB, each of which has a unique index, so I'm just curious if that algorithm would really be able to generate a unique ID considering that 78364164096 is only 1350 times more than 50000.  
Any ideas?  Should I use a 7-bit identifier or a 128-bit one? 

A:

I will assume the shorter ids provided by the shortid package to be full 56 bit long.  But most likely they take 56-bit long space (7 bytes) but only something like 42-bit long payload. 
Both 56-bit and 128-bit ids are subject to collision.  The difference is the probability of having a collision.  I think the 56-bit one REQUIRE you to be able to handle collisions, so you'll end up having a more complex code.  The 128-bit is quite unlikely to produce collisions to the point of generally not being considered. 
For the sake of simplicity and safety, I would choose the time proven 128-bit.