How bases react to increase in records?

Question

MySQL

If you work with data from php and every hour there will be about 3000 more records in the database. - Chat.
Let's assume about +70,000 per day, respectively, for 10 days about +700,000
Let's assume this will work on Amazon or DO or somewhere else in one of the cloud bases, with a 1.5gz 1ram machine.

1. How will this affect MYSQL×AURORA×MONGODB×DYNAMODB databases?
   
2. In how many days will the noticeable slowdown of the database for writing-reading begin?
   
3. Which one is better to take for these purposes, taking into account working with php?
   
4. What is the actual performance in your experience?
   

Answer 1

If this is a chat, then it is not clear why to keep the archive in one table. Clean up once a day. Or in the trash, or in the backup.

Answer 2

Do a test.

Answer 3

I would keep the "tail" of the chat (message flow) of public rooms in the memory of the socket server.
And saved in base - only necessary through parsing.
For dialogues - would use base with procedural selection.
Once a day - table backup.

Answer 4

For muscle, set up partitions and you will be happy