I'm considering to use Apache Flink to process some stream data in my project.
However, I was told that Flink may need much RAM by a friend. Also, I've found something which told me the same thing: https://www.quora.com/What-is-the-difference-between-Apache-Flink-and-Apache-Spark
For now I haven't learnt a lot about Flink, I just succeeded in installing it and running the Word Count example.
So I'm wondering why Flink needs much RAM. What is the mainly reason? Some disadvantage of Flink itself? Or saving the historical data? or anything else?
Can I use something like Redis to avoid this issue?