Rahul Mishra

lambda functions

Serverless Architecture & Lambda Functions

Serverless architecture is a design pattern that allows developers to build and run applications and services without having to worry about infrastructure or compute resources.

bloom filter

Probabilistic data structures & Bloom filters

Probabilistic data structures are data structures used to store data in a way that helps us find answers to certain types of queries quickly and accurately.

Lua

Redis Lua Scripting

With Lua scripts, complex Redis commands can be executed in an atomic way on the server in an efficient way. In this article, we will see how Lua scripts work with examples.

Redis Partitioning

Redis Partitioning And Redis Cluster Local Setup

In this article, we will learn about Redis partitioning, particularly about Redis Cluster, we will understand the use-cases of partitioning. In the latter half, we will be setting up the Redis cluster locally as well. From the official doc: Partitioning is the process of splitting your data into multiple Redis

Redis-Replication

Redis Replication

Redis replication is the process that allows Redis instances to be exact copies of master instances. Replication by default is an asynchronous process. Redis replication is non-blocking on the master side as well as on the replica side. This means that the master will continue to handle queries when one

charset

Charset and Collation in MySql

A character set is a set of symbols and encodings. And a collation is a set of rules for comparing and sorting characters in a character set. A charset must contain at least 1 default collation. For Mysql 8.0 the default MySQL server character set and collation are utf8mb4

n+1

Fixing N+1 query problem in Django

N+1 is a very common data-access pattern problem where a query is executed for every result of a previous query. If the definition looks cryptic, let's understand this problem with an example. We have created Country, Musician and Album tables with 20 rows in Album, 10 rows in Musician,

Django

Django Custom Middleware

Django middleware is a way to globally alter requests and responses ie. middlewares are layers of business logic that will be applied to all requests and responses. Consider an example to add logging for all requests, then the ideal way would be to add a middleware layer for the same,

Git

What are Git-hooks & How to use them?

Git hooks are scripts that Git automatically executes before or after events like commit, push, or receive. But why would anyone want to run scripts on git events? Well, let's see a few use-cases. Suppose you are working in a team and want to enforce a certain commit policy, let's

replication

Part-II: How Replication Works In MySql

In the first part of this blog-post series, we looked at the theoretical side of how replication works, in this blog post, we will set up replication and see all the components involved in the replication process, what tables keep the metadata about the replication process, what causes replication lag

replication

Part I: How Replication Works In MySql

In this article, we will understand what replication is, the traditional and the new way of replication, the different components involved in replication, and other important aspects of replication. MySQL replication is a process of replication of data from one master/source MySQL database server to one or more MySQL

Django

What Is Django Model Manager?

Django Model Manager is the interface through which database query operations are provided to Django models. objects is the default model manager and each model needs to have at least one model manager. Let's see a few use-cases when we can use model managers and when to use custom model

Elasticsearch

Part II: How Elasticsearch Works Internally

In the first part of the article, we saw data structures used under the hood and some operations that are done to make text search better, in this part, we will see the High-Level Architecture of Elasticsearch. We will understand what are segments, what elasticsearch indexes are made of, what

Elasticsearch

Part I: How Elasticsearch Works Internally

Elasticsearch is mostly used for full-text searches, however, elasticsearch is much more powerful than that and can be used in multiple cases like auto-completer, spell checker, alerting engine, log aggregator, and as a general-purpose document store. By definition, elasticsearch is a distributed, analytics engine for all types of data, including

Pointers

Beginners Guide To Pointers

Pointers can be tricky to understand in the beginning, this guide will help you visualize what pointers are and why are they useful. Before understanding pointers, let's understand how variables are stored in the memory address. Consider memory address as a continuous block that can store data, memory address can

Security

How to fix CORS Errors?

We all have encountered CORS errors in web-app development, in this article, we will understand what are these errors, what causes these errors in the first place, and how to fix these errors. Before fixing the issue, in order to understand CORS Errors, we first need to understand what are

Celery

What Is Django-Celery?

In this article, we will understand what asynchronous processing is, how to set up asynchronous processing for a Django project and what are the use-cases. Let's start with the problem statement, lets say you have a website and on signup, you want to send an email to the new customer,

Index

Part II: How Indexes Work In Mysql

In the first part of the article series, we understood what indexes are and how indexes work internally. In this part, we will look into multi-columnar indexes, ordering in indexes, and pitfalls in using indexes. We know that MySQL will only use one index per table per query. Therefore, if

Database

How Do Indexes Work In Mysql?

In this article series, we will dig deep into what indexes are, how it works, what are the advantages and disadvantages of using an index, multi-column indexes, and what are the pitfalls or gotchas of using an index. We have often come across the example of the index in a

ContentType

How To Use GenericForeignKeys In Django

In the first part of the article, we learned about the contenttypes framework and the ContentType model. In this article, we will see how that is being used in the implementation of Generic Foreign Keys. Let's first understand when we can need a generic foreign key, consider a case, where

ContentType

Understanding Django ContentType

In this series, we will understand Django's ContentType and what is GenericForeignKey with examples. contenttypes is a Django app that can track all of the models installed in our Django-powered project, providing a high-level, generic interface for working with our models. If we check in settings INSTALLED_APPS we can

distributed-systems

What Is CAP Theorem?

To understand CAP Theorem, first, we need to understand about network partitioning. Network partitioning occurs when a cluster of interconnected nodes breaks into two or more partitions and the nodes in each partition are unable to communicate with nodes in the other partitions. This happens because the network is unreliable,

Django

Select Related Vs Prefetch Related In Django

select_related and prefetch_related are ways to optimize database querying patterns when accessing related items. Both works on the same principle of prefetching data from the database, however, they take different approaches to do so. We will be using a decorator to print all the stats for the query.

redis-pipeline

What is Redis Pipeline

Redis clients and servers communicate with each other using a protocol called RESP (REdis Serialization Protocol) which is TCP-based. In TCP-based protocol, server and client communicate with request/response model. Redis also works the same way, the client sends a request, the server processes the command while the client waits

Database

Transaction Isolation Levels In MySql (InnoDB)

First, let's break the heading, a Transaction is a sequential group of statements, queries, or operations that performs as a single work unit that can be committed or rolled back. Next, Isolation is the I of ACID properties, isolation refers to the ability to concurrently process multiple transactions in a