I thought to create a quick tip post which is kind of lesson learnt, so that every time I learn something can add here and which could help others too. These examples here are not something I have created to support the points which I have mentioned below. Whereas these are the real code snippets of a project. Where team has written code in this manner and given feedback to improve their code. So I thought it would be better if I write a Lesson learnt post which could help other to be aware of mistake they can make while

This topic is about using Redis and LUA script in Rails. Before proceeding, you may like to read [ Introduction to LUA script with Redis][1] Redis doesn't have any command to calculate total number of keys We'll use [zrangebyscore][2] to find number of members between index range. Instal [redis-rb][3] Start rails console Prepare a dataset based on timestamp > t10 = 10.minutes.ago => 1386935151 > t20 = 20.minutes.ago => 1386934568 > t30 = 30.minutes.ago => 1386933971 > t40 = 40.minutes.ago => 1386933374 This is non-realistic data, may vary for you. Populate redis with Sorted Set > redis = Redis.new # initialize redis => # zadd -