Mysql representation in redis - redis

Question

I dont have any experience in redis and i would like to use it to cache mysql php results but it getting abit complicated.
In mysql i have two tables
tbl_users: id, username, first_name, last_name
tbl_orders: order_id, order_name, order_date........
Suppose i would like to store both users and orders tables records in redis i picured a json looking like
{
"users":{
"1":{username:"jane", first_name:"user1", last_name:".."}
"2":{username:"jane", first_name:"user1", last_name:".."}
...........
}
"orders":{
"1":{order_name:"jane", order_date:"user1",....}
"1":{order_name:"jane", order_date:"user1", .....}
}
}
}
In this case should i create two redis servers, one for users and other for orders or how should i go about this.

Answer 1

First, you should read An introduction to Redis data types and abstractions, to understand what Redis is and what it can do.
It sounds like you have 3 things you want to cache in Redis:
A specific user:
This is what Redis is best at.
SET user:1 '{username:"jane", first_name:"user1", last_name:".."}',
then read the user JSON back with GET user:1
All users:
This probably isn't worth caching in Redis, since MySQL will be quite fast at returning all the rows in tbl_users already.
You could use a Redis list (via LPUSH and getting all of them LRANGE {listname} 0 -1) to cache it.
But you're just duplicating the functionality of a database table at this point, so I really wouldn't recommend it.
Orders for a specific user:
Again, MySQL should be able to do this efficiently for you, with a good index on tbl_orders, but Redis can cache it using a list as well.