Articles

Performance Monitoring and Tuning 🇺🇸

May 11, 2025
Category: Databases Notes

Performance monitoring and tuning involve the continuous process of measuring, analyzing, and optimizing the performance of a database system. In today's data-driven world, ensuring that databases operate efficiently is crucial for maintaining user satisfaction, maximizing resource utilization, and ...

Sql Injection 🇺🇸

May 11, 2025
Category: Databases Notes

SQL Injection Attacks are a security concern in web applications. We'll explore how these attacks occur, examine concrete examples, and discuss effective prevention strategies. By the end of this journey, you'll have a solid understanding of SQL Injection and how to protect your applications from su...

Crash Recovery in Databases 🇺🇸

May 11, 2025
Category: Databases Notes

Crash recovery is a important component of database systems that ensures data consistency and durability despite unexpected events like power outages, hardware failures, or software crashes. By design, databases must be capable of returning to a reliable state after a failure occurs. This is largely...

Materialized Views 🇺🇸

May 11, 2025
Category: Databases Notes

Materialized views are a database feature that allows you to store the result of a query physically on disk, much like a regular table. Unlike standard views, which are virtual and execute the underlying query each time they are accessed, materialized views cache the query result and can be refreshe...

Master Standby Replication 🇺🇸

May 11, 2025
Category: Databases Notes

Master-Standby replication is a widely adopted database replication topology where a primary database server, known as the master, replicates data to one or more secondary servers called standbys. This setup enhances data availability, fault tolerance, and load balancing within a database system. St...

Synchronous vs Asynchronous Replication 🇺🇸

May 11, 2025
Category: Databases Notes

Replication is an important concept in database systems, involving the copying of data from one database server, known as the primary, to one or more other servers called replicas. This process enhances data availability, fault tolerance, and load balancing across the system. Understanding the two m...

Stored Procedures and Functions 🇺🇸

May 11, 2025
Category: Databases Notes

In the realm of relational databases, stored procedures and functions are powerful tools that allow developers to encapsulate reusable pieces of SQL code. They enhance performance by caching execution plans, promote code reusability, and keep business logic close to the data. By understanding how to...

Introduction to Distributions 🇺🇸

May 11, 2025
Category: Statistics Notes

A distribution is a function that describes the probability of a random variable. It helps to understand the underlying patterns and characteristics of a dataset. Distributions are widely used in statistics, data analysis, and machine learning for tasks such as hypothesis testing, confidence interva...

Statistical Moments 🇺🇸

May 11, 2025
Category: Statistics Notes

In both statistics and mechanics the word moment measures how much "leverage" the values of a quantity exert about a chosen reference point. In statistics the leverage is exerted by probability mass, in mechanics by physical mass, but the mathematics is identical: take a distance from the reference ...

Sed and Awk 🇺🇸

May 06, 2025
Category: Linux Notes

sed (Stream Editor) and awk are powerful command-line utilities that originated from Unix and have become indispensable tools in Unix-like operating systems, including Linux and macOS. They are designed for processing and transforming text, allowing users to perform complex text manipulations with s...

Virtual Machines 🇺🇸

May 06, 2025
Category: Linux Notes

Virtual machines have revolutionized the way we approach computing resources by enabling the creation of software-based representations of physical hardware. This concept, known as virtualization, allows us to emulate hardware components like CPUs, memory, storage devices, and network interfaces, pr...

Intro to Replication 🇺🇸

May 06, 2025
Category: Databases Notes

Database replication is the process of copying and maintaining database objects, such as tables and records, across multiple servers in a distributed system. This technique ensures that data remains consistent and up-to-date on all servers, enhancing availability, fault tolerance, and scalability. B...

Sqlite 🇺🇸

May 06, 2025
Category: Databases Notes

SQLite is a self-contained, serverless, and zero-configuration SQL database engine that's known for its simplicity and efficiency. Unlike traditional databases that require a separate server to operate, SQLite operates directly on ordinary disk files. This makes it an ideal choice for small to mediu...

Triggers 🇺🇸

May 06, 2025
Category: Databases Notes

Welcome back to our exploration of SQL! Today, we're delving into the world of triggers, a powerful feature that allows you to automate actions in response to specific events in your database. Triggers can help maintain data integrity, enforce business rules, and keep an audit trail of changes—all w...

Indexing Strategies 🇺🇸

May 06, 2025
Category: Databases Notes

Database indexing is like adding bookmarks to a large textbook; it helps you quickly find the information you need without flipping through every page. In the world of databases, indexes significantly speed up data retrieval operations, making your applications faster and more efficient. However, in...

Database Pages 🇺🇸

May 06, 2025
Category: Databases Notes

Diving into the fundamentals of database systems reveals that database pages are essential units of storage used to organize and manage data on disk. They play a pivotal role in how efficiently data is stored, retrieved, and maintained within a Database Management System (DBMS). Let's explore what d...

Partitioning vs Sharding 🇺🇸

May 06, 2025
Category: Databases Notes

When a database begins to sag under the weight of its own success, engineers reach for two closely-related remedies: partitioning and sharding. Both techniques carve a huge dataset into smaller slices, yet they do so at very different depths of the stack. By the time you finish these notes you shoul...

Consistent Hashing 🇺🇸

May 06, 2025
Category: Databases Notes

Imagine you're organizing books in a vast library with shelves arranged in a circle. Each book’s position is chosen by the first letter of its title, looping back to the beginning after Z. When you install a new shelf or remove one, you’d prefer not to reshuffle every book—only a small, predictable ...

Simple Linear Regression 🇺🇸

May 06, 2025
Category: Statistics Notes

Simple linear regression is a statistical method used to model the relationship between a single dependent variable and one independent variable. It aims to find the best-fitting straight line through the data points, which can be used to predict the dependent variable based on the independent varia...

Simpsons Rule 🇺🇸

May 05, 2025
Category: Numerical Methods

Simpson's Rule is a powerful technique in numerical integration, utilized for approximating definite integrals when an exact antiderivative of the function is difficult or impossible to determine analytically. This method enhances the accuracy of integral approximations by modeling the region under ...

Data Integrity 🇺🇸

May 04, 2025
Category: Databases Notes

Data integrity is a fundamental concept in database design and management that ensures the accuracy, consistency, and reliability of the data stored within a database. Think of it as the foundation of a building; without a strong foundation, the entire structure is at risk. Similarly, without data i...

Eventual Consistency 🇺🇸

May 04, 2025
Category: Databases Notes

Imagine a distributed system with multiple nodes—servers or databases—that share data. When an update occurs on one node, it doesn't instantly reflect on the others due to factors like network latency or processing delays. However, the system is designed so that all nodes will eventually synchronize...

Yule Walker Equations 🇺🇸

May 04, 2025
Category: Statistics Notes

The Yule-Walker equations are a set of linear relationships that tie the autocovariances/autocorrelations of a stationary autoregressive (AR $p$) process to its parameters. They are the work-horse for parameter estimation, diagnostic checking, and theoretical analysis of AR models...

Trapezoidal Rule 🇺🇸

May 04, 2025
Category: Numerical Methods

The Trapezoidal Rule is a fundamental numerical integration technique employed to approximate definite integrals, especially when an exact antiderivative of the function is difficult or impossible to determine analytically. This method is widely used in various fields such as engineering, physics, a...

Regression 🇺🇸

May 04, 2025
Category: Numerical Methods

Regression analysis and curve fitting are important tools in statistics, econometrics, engineering, and modern machine-learning pipelines. At their core they seek a deterministic (or probabilistic) mapping $\widehat f: \mathcal X \longrightarrow \mathcal Y$ that minim...

Newton Polynomial 🇺🇸

May 04, 2025
Category: Numerical Methods

Newton’s Polynomial, often referred to as Newton’s Interpolation Formula, is another classical approach to polynomial interpolation. Given a set of data points $(x_0,y_0),(x_1,y_1),\dots,(x_n,y_n)$ with distinct $x_i$ values, Newton’s method constructs an interpolating polynomial in a form that make...

Bayesian vs Frequentist 🇺🇸

May 03, 2025
Category: Statistics Notes

Bayesian and frequentist statistics are two distinct approaches to statistical inference. Both approaches aim to make inferences about an underlying population based on sample data. However, the way they interpret probability and handle uncertainty is fundamentally different...

Lagrange Polynomial Interpolation 🇺🇸

May 03, 2025
Category: Numerical Methods

Lagrange Polynomial Interpolation is a widely used technique for determining a polynomial that passes exactly through a given set of data points. Suppose we have a set of $(n+1)$ data points $(x_0, y_0), (x_1, y_1), \ldots, (x_n, y_n)$ where all $x_i$ are distinct. The aim is to find a polynomial $L...

Visualization Techniques 🇺🇸

April 26, 2025
Category: Vtk Examples

In modern data analysis, visual exploration often becomes the fastest — and sometimes the only — way to grasp relationships hidden in large, multi-dimensional datasets. VTK meets this challenge by bundling dozens of state-of-the-art algorithms behind a consistent, object-oriented API that can be com...

Tar and Gzip 🇺🇸

April 19, 2025
Category: Linux Notes

Working with files on Unix-based systems often involves managing multiple files and directories, especially when it comes to storage or transferring data. Tools like tar and gzip are invaluable for packaging and compressing files efficiently. Understanding how to use these commands can simplify task...

Project Structure 🇺🇸

April 05, 2025
Category: Frontend Notes

A well-organized project structure is fundamental to the success of any software development project. It ensures that the code remains maintainable, scalable, and understandable, especially as the project grows in complexity and size. Adapting the structure based on the project's needs is essential ...

Multiple Comparisons 🇺🇸

March 26, 2025
Category: Statistics Notes

When conducting multiple hypothesis tests simultaneously, the likelihood of committing at least one Type I error (falsely rejecting a true null hypothesis) increases. This increase is due to the problem known as the "multiple comparisons problem" or the "look-elsewhere effect". The methods to addres...

Probability Tree 🇺🇸

February 20, 2025
Category: Statistics Notes

Probability trees are a visual representation of all possible outcomes of a probabilistic experiment and the paths leading to these outcomes. They are especially helpful in understanding sequences of events, particularly when these events are conditional on previous outcomes...

Logistic Regression 🇺🇸

February 07, 2025
Category: Statistics Notes

Logistic regression is a statistical method used for modeling the probability of a binary outcome based on one or more predictor variables. It is widely used in various fields such as medicine, social sciences, and machine learning for classification problems where the dependent variable is dichotom...

Selinux 🇺🇸

January 20, 2025
Category: Linux Notes

Security-Enhanced Linux (SELinux) is a robust security module integrated into the Linux kernel that provides a mechanism for supporting access control security policies. Unlike traditional discretionary access control (DAC) systems where users have control over their own files and processes, SELinux...