Saad Hossain

1609740720

Redis Crash Course 2021

In this crash course, you will get the basic fundamentals of Redis, its advantages, the supported data types and some of the useful commands to use on the Redis client terminal.
Also, how to install it on your system (Windows OS) and how to get it running.

Index 📝

00:00 Introduction
00:32 Presentation
03:25 Install Redis (Windows OS)
07:14 Running Redis Server and Client
07:34 Commands and Datatypes

Subscribe: https://www.youtube.com/channel/UC7EVSn5inapL20oPSwAwEUg

#redis

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Redis Crash Course 2021
Loma  Baumbach

Loma Baumbach

1596679140

Redis Transactions & Long-Running Lua Scripts

Redis offers two mechanisms for handling transactions – MULTI/EXEC based transactions and Lua scripts evaluation. Redis Lua scripting is the recommended approach and is fairly popular in usage.

Our Redis™ customers who have Lua scripts deployed often report this error – “BUSY Redis is busy running a script. You can only call SCRIPT KILL or SHUTDOWN NOSAVE”. In this post, we will explain the Redis transactional property of scripts, what this error is about, and why we must be extra careful about it on Sentinel-managed systems that can failover.

Redis Lua Scripts Diagram - ScaleGrid Blog

Transactional Nature of Redis Lua Scripts

Redis “transactions” aren’t really transactions as understood conventionally – in case of errors, there is no rollback of writes made by the script.

Atomicity” of Redis scripts is guaranteed in the following manner:

  • Once a script begins executing, all other commands/scripts are blocked until the script completes. So, other clients either see the changes made by the script or they don’t. This is because they can only execute either before the script or after the script.
  • However, Redis doesn’t do rollbacks, so on an error within a script, any changes already made by the script will be retained and future commands/scripts will see those partial changes.
  • Since all other clients are blocked while the script executes, it is critical that the script is well-behaved and finishes in time.

The ‘lua-time-limit’ Value

It is highly recommended that the script complete within a time limit. Redis enforces this in a weak manner with the ‘lua-time-limit’ value. This is the maximum allowed time (in ms) that the script is allowed to run. The default value is 5 seconds. This is a really long time for CPU-bound activity (scripts have limited access and can’t run commands that access the disk).

However, the script is not killed when it executes beyond this time. Redis starts accepting client commands again, but responds to them with a BUSY error.

If you must kill the script at this point, there are two options available:

  • SCRIPT KILL command can be used to stop a script that hasn’t yet done any writes.
  • If the script has already performed writes to the server and must still be killed, use the SHUTDOWN NOSAVE to shutdown the server completely.

It is usually better to just wait for the script to complete its operation. The complete information on methods to kill the script execution and related behavior are available in the documentation.

#cloud #database #developer #high availability #howto #redis #scalegrid #lua-time-limit #redis diagram #redis master #redis scripts #redis sentinel #redis servers #redis transactions #sentinel-managed #server failures

Sival Alethea

Sival Alethea

1624395600

MongoDB with Python Crash Course - Tutorial for Beginners. DO NOT MISS!!!

Learn the most popular NoSQL / document database: MongoDB. In this quickstart tutorial, you’ll be up and running with MongoDB and Python.
⭐️Course Contents⭐️
⌨️ (0:00:00) Welcome
⌨️ (0:04:33) Intro to MongoDB
⌨️ (0:07:49) How do document DBs work?
⌨️ (0:10:34) Who uses MongoDB
⌨️ (0:13:02) Data modeling
⌨️ (0:16:30) Modeling guidelines
⌨️ (0:22:11) Integration database
⌨️ (0:24:23) Getting demo code
⌨️ (0:30:07) How ODMs work?
⌨️ (0:32:55) Introduction to mongoengine
⌨️ (0:34:01) Demo: Registering connections with MongoEngine
⌨️ (0:37:20) Concept: Registering connections
⌨️ (0:39:14) Demo: Defining mongoengine entities (classes)
⌨️ (0:45:22) Concept: mongoengine entities
⌨️ (0:49:03) Demo: Create a new account
⌨️ (0:56:55) Demo: Robo 3T for viewing and managing data
⌨️ (0:58:18) Demo: Login
⌨️ (1:00:07) Demo: Register a cage
⌨️ (1:10:28) Demo: Add a bookable time as a host
⌨️ (1:16:13) Demo: Managing your snakes as a guest
⌨️ (1:19:18) Demo: Book a cage as a guest
⌨️ (1:33:41) Demo: View your bookings as guest
⌨️ (1:41:29) Demo: View bookings as host
⌨️ (1:46:18) Concept: Inserting documents
⌨️ (1:47:28) Concept: Queries
⌨️ (1:48:09) Concept: Querying subdocuments with mongoengine
⌨️ (1:49:37) Concept: Query using operators
⌨️ (1:50:24) Concept: Updating via whole documents
⌨️ (1:51:46) Concept: Updating via in-place operators
⌨️ (1:54:01) Conclusion

📺 The video in this post was made by freeCodeCamp.org
The origin of the article: https://www.youtube.com/watch?v=E-1xI85Zog8&list=PLWKjhJtqVAbnqBxcdjVGgT3uVR10bzTEB&index=10
🔥 If you’re a beginner. I believe the article below will be useful to you ☞ What You Should Know Before Investing in Cryptocurrency - For Beginner
⭐ ⭐ ⭐The project is of interest to the community. Join to Get free ‘GEEK coin’ (GEEKCASH coin)!
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Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#mongodb #python #python crash course #mongodb with python crash course - tutorial for beginners #beginners #mongodb with python crash course

Mike doctor

Mike doctor

1624226400

THE CRYPTO CRASH OF 2021 (Should you Invest now?) DO NOT MISS!!!

In this video, I’m going over the recent cryptocurrency crash and what you should know about it. We’ll go into what caused it, why this is/is not normal, and what you should do as an investor.

This is the largest crypto crash by market cap we have seen - and it’s definitely scary. Bitcoin, ethereum, and pretty much every single notable crypto out there is down today. These are my thoughts surrounding the news, important things to know about the current climate, and what I personally will be doing with my crypto.
📺 The video in this post was made by Charlie Chang
The origin of the article: https://www.youtube.com/watch?v=lAQ0FGdGSZI
🔺 DISCLAIMER: The article is for information sharing. The content of this video is solely the opinions of the speaker who is not a licensed financial advisor or registered investment advisor. Not investment advice or legal advice.
Cryptocurrency trading is VERY risky. Make sure you understand these risks and that you are responsible for what you do with your money
🔥 If you’re a beginner. I believe the article below will be useful to you ☞ What You Should Know Before Investing in Cryptocurrency - For Beginner
⭐ ⭐ ⭐The project is of interest to the community. Join to Get free ‘GEEK coin’ (GEEKCASH coin)!
☞ **-----CLICK HERE-----**⭐ ⭐ ⭐
Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#bitcoin #blockchain #crypto #crypto crash #the crypto crash of 2021 #the crypto crash of 2021 (should you invest now?)

Mike doctor

Mike doctor

1624384800

The Stock Market Crash of 2021 (How to Profit BIG)

Is the stock market crashing in 2021? In this video, we are going over why and when the stock market will crash, what you can do to prepare for it and profit, and what stocks I’m buying right now that are great long term holds.

Make sure to watch until the end, as I will go over what’s happening with the markets right now, what’s causing it, and my sentiment about why a crash will occur.

📺 The video in this post was made by Charlie Chang
The origin of the article: https://www.youtube.com/watch?v=vOIxDL5XCjY
🔺 DISCLAIMER: The article is for information sharing. The content of this video is solely the opinions of the speaker who is not a licensed financial advisor or registered investment advisor. Not investment advice or legal advice.
Cryptocurrency trading is VERY risky. Make sure you understand these risks and that you are responsible for what you do with your money
🔥 If you’re a beginner. I believe the article below will be useful to you ☞ What You Should Know Before Investing in Cryptocurrency - For Beginner
⭐ ⭐ ⭐The project is of interest to the community. Join to Get free ‘GEEK coin’ (GEEKCASH coin)!
☞ **-----CLICK HERE-----**⭐ ⭐ ⭐
Thanks for visiting and watching! Please don’t forget to leave a like, comment and share!

#bitcoin #blockchain #stock #the stock market crash #the stock market crash of 2021 #the stock market crash of 2021 (how to profit big)

Alex Riley

Alex Riley

1607510226

Best Web App Ideas To Make Money In 2021 - Application Startup Guide

Some Popular Web App Ideas for 2021

Are you looking for best web application business ideas that make money in 2021?

There are lots of simple web app ideas but all those web application business ideas do not make money.

Read More

#trending web app ideas 2021 #trending web application ideas 2021 #web application ideas 2021 #web app ideas 2021 #new web app ideas 2021 #evergreen web app ideas 2021