Chapter 1 - Reliable, Scalable and Maintainable Applications In [[Reading DDIA - Part 1]] , I read about Reliability. The next section is Scalability . First let me talk about the assumptions I made about the term Scalability, what I understand from it prior to reading Martin Kleppman’s thoughts on the topic - What is a scalable system? My thoughts prior to reading the section - Scale refers to how does a system grow. Growth can be needed for multiple reasons - ...
(Here’s the preface in case you missed it - [[Reading DDIA - Preface]]) Chapter 1 - Reliable, Scalable and Maintainable Applications This chapter’s goal is to effectively give us a high level overview of what this book is fundamentally about - Thinking about data systems along the axes of : Reliability Scalability Maintainability What is a reliable system? My thoughts before reading the section : A system that is available to return results/outputs that are expected of it when it is employed. If I’m accessing an API, if the API is available 99 out of 100 times, then its reliability is 99% If a server is available for 23 hrs 45 minutes per day then its availability is 23.75/24 = 98.9% But is availability == reliability? Let’s see. A reliable human is someone who does something that he says he will do or is expected to do every time. Similarly a reliable system is one that returns the expected results every time that they are used. An ATM is reliable if I can withdraw money from it in the denominations that I want, when I want it. For example, the ATM in Puttenahalli , JP Nagar is perpetually unavailable. Everytime I go there, the system is under maintenance. It is 0% reliable. Let’s read the chapter. ...
Over the next few weeks, I want to read a book that has been long-pending - “Designing Data Intensive Applications” by Martin Kleppman. I’ve been building data applications for a while now but most, if not all the learnings, have been through trial and error after error after error. I’ve learnt a decent bit from observing more senior engineers, architects, design documents and building architectures little by little on my own, but not yet I think, in a structured, deliberate manner. I’m hoping to learn that in this book along with the other books I will likely have to refer along the way. ...
Today, I’m experimenting with a new way of logging. An incremental account as opposed to a summarized one at the end of the day. Morning log - The plants did not require watering today as it rained heavily last night for quite a while. Breakfast procured, tea prepared and work has begun at an honest, early hour. A good, hopefully productive 2 hours to go before I am interrupted by other humans….unless I indulge in distracting myself before that. I also began reading my 5th Agatha Christie novel today - Poirot Investigates - Short stories involving the duo - Hastings’ and Poirot’s cases. The similarities between them and Watson and Sherlock of the Conan Doyle persuasion isn’t lost on me. But of course, this subject of comparisons has been of interest for decades to bloggers and literature students across the world. One read I found particularly interesting as I looked up the internet to support my immediately preceding comment was this - https://dirkdeklein.net/2018/04/13/when-arthur-conan-doyle-looked-for-agatha-christie/ .I must read up more on ACD’s “occultist” practices. But perhaps, that’s an activity for a later time. Off to work now.
I continued listening to Cabin Pressure today and completed it. Not much of an accomplishment since there were only 12 episodes of 28 minutes each. It’s a testament to how good of a show it was that I was listening to Episode 6, Season 2 and I remember feeling bummed out a little when I realised it was the last episode on the playlist, with the third season not yet in sight. ...
I bought two books on Jun 27, using a Champaca gift voucher that was about to expire. I didn’t need the books, but it was …there. So I ordered “Ways of Seeing” by John Berger and “Digital Minimalism” by Cal Newport. Now, the latter, I was really looking forward to because it’s ongoing and eventual goal to successfully subscribe to and practice the “philosophies” of digital minimalism - a topic highly relevant today and definitely more so, tomorrow. ...
I wrote a little about the book this show is based on, earlier this year. I’d absolutely loved it and ever since a dear friend, Reema, told me that the trailer for the Netflix show was out, I’d been excitedly awaiting its release, slated for December 29, 2021, which if you’ve still managed to keep track of time, was yesterday. It was a little late in the day that I realised that it was here and I waited for meeting after meeting to get over so I could start watching the show. ...
It was a bright summer (already?) day and I was in high spirits. And why not? I’d woken up early and on a Monday no less! Surely that was a sign of a good day? I left home to go to work at 8.45 AM as intended (but seldom carried out. Not today though. Another good sign). I got my vehicle out and was greeted by the familiar sound of the woman who comes everyday to take out the trash. This person who has no need to be on time has more sense of punctuality than the so-called skilled workers that we’re dubbed to be. I greeted her in the usual fashion as I do on the days that I’m able to match her time. The ride to the Metro station was uneventful and that in itself was pleasant. I saw the usual sights - vegetable peddlers idly pedalling away on their cycles to get to their usual circuits, no doubt. Shopkeepers chatting with each other as they opened the shutters to their shops ; some early birds had begun their ritual of praying to their gods for a good day of business. Familiar, pleasant sights. I smiled to myself as I continued riding leisurely. I was on time, there was no need to rush. ...
Today I learnt that there’s this term called Bildungsroman . I tripped upon it while I was pondering the commonalities between Harry Potter and Naruto , about how both of them were underdogs, cursed at birth - one with a horcrux, and the other with a curse-mark, grew up effectively with no one to love them till they were of a certain age but are both intended for great things and grow into their respective savior roles. The genre itself doesn’t require the main character to be a “hero”, but the stories do intend to show the psychological and moral growth of said character. ...
Padma sat by the window reading “Harry Potter and The Order of The Phoenix” for what was probably the fifteenth time. She’d already binged through Goblet of Fire. When she reached the chapter “Silver and Opals”, she looked up for the first time in three hours and out the window. The road outside was empty save for a cat that was scratching the neighbor’s door on the other side. “What if that were Minerva McGonagall?”, Padma thought to herself and chuckled, amused. She decided to give herself a break, leaned against the wall adjoining the window and closed her eyes, her mind buzzing with thoughts of Voldemort taking over Harry’s dreams and wondering if she might fall victim to that too, if she fell asleep just then. She’d just closed her eyes when the doorbell rang. “Now? Really?”, she muttered and made her way unwillingly to the front door. She peered through the peephole cautiously, but there was no one in sight. She slowly opened the door and heard a shuffling noise at her feet. It was the cat she’d seen, trying to nudge past her legs and into the house. Before she could make sense of the situation, it had already made a dash for the living room and paused at the edge of a straw mat by the poojai room. Padma, still bewildered looked outside one last time before she closed the door and wondered who had rung the doorbell. Surely, it wasn’t the cat?! She shook her head. The doorbell mystery could wait. There was a stray cat in her living room. She frowned and stared at her intruder who had by then decided that the mat was an enemy and must be destroyed. Padma meanwhile, had gathered her wits and gently started tiptoeing towards the cat; although what she would do once she approached it, she hadn’t thought about just yet. The cat was still pawing away at the mat, its concentration unwavering. Padma was now within petting distance from it. Now came the almighty question. What was she going to do? What could she do? Shooing it would only drive it deeper inside her house. She couldn’t just pick it up and take it outside her house.. could she? No, that was out of the question. For starters, she had no idea How to lift a cat. What if it scratched her face? No. That was out of the question. As she pondered, she slowly sat down behind the cat. Now she was level with its tail and just looking at it with a vacant expression, head tilted to a side, unable to decide what to do next. Meanwhile, the cat, who had evidently felt an alien presence around it, stiffened and looked around and with a loud and startled miaow backed a couple of steps away from Padma, who was equally startled by the feline shriek. Both looked at each other, the cat with its paws slightly lifted, ready to flee and the human with her hands behind her on the floor, a confused expression across her face. The human acted first. She raised her hands , in an expression of resignment and surrender and mouthed, “Okay, calm down. I am not going to hurt you”, even as a voice in her head said “You are talking…to a cat.”. Another voice in her head said “Yeah, what if it doesn’t know English?”. Padma chuckled for the second time that day having amused herself again. She shook her head again. “This is not the time, Padma.”, she thought and began inching away from the cat. Slowly, she got up and walkedto the kitchen, all the while watching the cat through the corner of her eye. “I might as well get you some milk”, she called out, still aware that her visitor probably didn’t understand the noise that the owner of the house was making. She heated up a bowl of milk to a moderate temperature, took the bowl and placed it cautiously at the edge of the now-somewhat-worse-for-the-wear mat. The cat looked up at Padma with wide eyes and then at the bowl of milk still not moving from its position. She took the cue and backed away. This prompted it to approach the bowl and sniff its contents. Satisfied, it dipped its tongue into the milk and started lapping it up, its eyes initially on Padma and eventually on the contents of the bowl. It must have been really hungry, for it finished drinking within a matter of minutes and placed a foot on the bowl when it found that there was no more milk to drink. It looked up at a smiling Padma, who was glad that her offering had been so well accepted. “Do you want more?”, she enquired, not really expecting a response. Those expectant eyes were answer enough and she went back to the kitchen area to heat up some more milk. This time however, the cat followed her and began poking at the slippers she had left at the entrance of the kitchen. She refilled the bowl and placed it again, this time closer to the cat that did not inch away, but was looking intently as the bowl moved from human to floor. The pace at which the bowl was emptied this time was even quicker, but it evidently sated the cat’s hunger, for it did not look up again at Padma, but moved towards its favorite torn-up mat and lay down. She heated up a glass of milk, this time for herself, picked up the Harry Potter book from near the window and sat next to the cat. She took a sip of milk and opened the page to Silver and Opals and started reading out loud, a gentle palm on the cat’s head - “Where was Dumbledore, and what was he doing?…”. She paused. “What was Dumbledore doing, Minerva?”, she addressed the cat, took another sip of milk and smiled. ...