In computer science, write-ahead logging (WAL) is a family of techniques for providing atomicity and durability (two of the ACID properties) in database systems. A write ahead log is an append-only auxiliary disk-resident structure used for crash and transaction recovery. The changes are first recorded in the log, which must be written to stable storage, before the changes are written to the database. The main functionality of a write-ahead log can be summarized as: * Allow the page cache to buffer updates to disk-resident pages while ensuring durability semantics in the larger context of a database system. * Persist all operations on disk until the cached copies of pages affected by these operations are synchronized on disk. Every operation that modifies the database state has to be logged on disk before the contents on the associated pages can be modified * Allow lost in-memory changes to be reconstructed from the operation log in case of a crash. In a system using WAL, all modifications are written to a log before they are applied. Usually both redo and undo information is stored in the log. The purpose of this can be illustrated by an example. Imagine a program that is in the middle of performing some operation when the machine it is running on loses power. Upon restart, that program might need to know whether the operation it was performing succeeded, succeeded partially, or failed. If a write-ahead log is used, the program can check this log and compare what it was supposed to be doing when it unexpectedly lost power to what was actually done. On the basis of this comparison, the program could decide to undo what it had started, complete what it had started, or keep things as they are. After a certain amount of operations, the program should perform a checkpoint, writing all the changes specified in the WAL to the database and clearing the log. WAL allows updates of a database to be done in-place. Another way to implement atomic updates is with shadow paging, which is not in-place. The main advantage of doing updates in-place is that it reduces the need to modify indexes and block lists. ARIES is a popular algorithm in the WAL family. Modern file systems typically use a variant of WAL for at least file system metadata; this is called journaling. (Wikipedia).
How to Write a Blog Post That Gets MASSIVE Traffic
In this video I’m going to show you how to write a blog post the right way. Specifically, you’re going to learn how to write blog posts that get traffic, social shares, backlinks, first page Google rankings, and more. With that, here’s a quick preview of the techniques I’ll cover in the
From playlist How to Get Higher Google Rankings
From playlist Study Hacks
Logging in JavaScript Best Practices
Logging is an age-old practice, but we're still doing some major things wrong. Joe will be taking us through various aspects of logging: - Why to log - When to log - How to log well - JS Tooling/Testing for logging Talk by Joe Reeve at the JS Roundabout meetup. Recorded by Pusher.com. Ch
From playlist Talks
How to lead students to an activity from a book
A simple way of decreasing the scroll of death and making your activities more accessible.
From playlist How to add a book in your course
In this HTML video, you’ll learn about paragraphs. They help to organize text on websites. We hope you enjoy! To learn more, check out our Basic HTML tutorial here: https://edu.gcfglobal.org/en/basic-html/ #html #htmlparagraphs #coding
From playlist HTML
Editing Wikipedia: Communicating with others using the Talk page and Help Desk
This video demonstrates how to create a Talk page, how to sign your username on a Talk page and where to go to ask for help from the Wikipedia community.
From playlist Wikipedia editing using Visual Editor
HTML / CSS lesson 3 - Wrap lines, Youtube playlists
In this lesson I create links to my Youtube playlists. We also talk about line breaks (wrap lines) and smaller headings (h1,h2,h3,h4 etc). Editing environment: CPanel Pro 1.0
From playlist HTML / CSS tutorials
[Twitch] Hacknet walkthrough - part 1 - Let's get to hacking
Join me on Twitter: http://twitter.com/WhatDaMath Facebook: https://www.facebook.com/whatdamath Hello and welcome to What Da Math. This is an attempt at beating the awesome new game called Hacknet. The video was broadcasted on Twitch. http://www.twitch.tv/whatdamath The game is availabl
From playlist Hacknet
Properties of Logarithms - Understand The Basics
Properties of logarithms are essential to solve logarithmic and exponential equations. This video will explain all the properties of logs and how to expand and condense expressions. For more math help please visit http://tabletclass.com
From playlist Pre-Calculus / Trigonometry
How to Solve Logarithmic and Exponential Equations (20 Examples)
In this video I will show you how to solve logarithmic and exponential equations. I do 20 examples and cover most of the common cases. I hope this helps someone. 00:00 Start 00:06 Exponential Equation with Single e 01:28 Logarithmic Equation with one Natural Logarithm 02:49 Logarithmic Eq
From playlist Math Tutorials
We calculate the closed form of a nice infinite series two different ways. Please Subscribe: https://www.youtube.com/michaelpennmath?sub_confirmation=1 Merch: https://teespring.com/stores/michael-penn-math Personal Website: http://www.michael-penn.net Randolph College Math: http://www.ra
From playlist Interesting Sums
3.9 Derivatives of Exponential and Logarithmic Functions
OpenStax Calculus Volume 1
From playlist Calculus 1
3.9 Derivatives of Exponential and Logarithmic Functions
OpenStax Calculus Volume 1
From playlist OpenStax Calculus Volume 1 (By Objectives)
On means of binomial coefficients.
We look at some limits related to arithmetic and geometric means of binomial coefficients. Strategy for the second part: math.illinois.edu/~hildebr/putnam/problems/mock11sol.pdf Please Subscribe: https://www.youtube.com/michaelpennmath?sub_confirmation=1 Merch: https://teespring.com/sto
From playlist Interesting Limits
Calculus 1-Differentiation part 3 Log functions
Calculus 1-Differentiation part 3 Log functions You can go here to practice your calculus https://sites.google.com/site/gotomathcalculus/
From playlist Calculus 1
Understanding and Sketching Individual Bode Plot Components
In this video we illustrate how 7 types of simple transfer functions contribute to a bode plot. We refer to these as ‘components’ and will cover the following: 1. Single real pole 2. Single real zero 3. Pole at the origin (integrator) 4. Zero at the origin (differentiator) 5. Pair of com
From playlist Control Theory
How to Work with Wikipedia Sandbox
This is a short video that helps students or editors of Wikipedia to access and edit in the Sandbox of their user account. This was made for the Wiki Edu Project. I do not own or hold copyright over any aspect of the Wikipedia site or its pages. ***There is no audio***
From playlist Wikipedia Education Dashboard Tutorials