Which NoSQL is more productive: MongoDB or Cassandra?

Question

MongoDB

I choose the most lightweight database for storing a large amount of data (for example, store the text of 50,000 documents of 300 kb each), so that it can work stably and without any brakes not only on a hi-end PC, but at least on a PC with 4GB of RAM and similar level with other components.
In total, the choice fell between MongoDB and Cassandra, as between the most (in my opinion, correct if this is not so) productive options.
Tasks: Search through documents (find the N-text in the file and display all the files where it was found, etc.), replace the text in these same files and maybe a few more, but also related to text processing
But I don’t know what the features are behavior of each:
1. Which database is more lightweight and performant with such data volumes?
2. Which one is more stable?
3. Which one has fewer setup problems?

Answer 1

1. PostgreSQL
   
2. PostgreSQL
   
3. PostgreSQL
   

Answer 2

elasticsearch