Volodymyr Pavlyshyn Volland

Notes on Martin Kleppmann's excellent Designing Data-Intensive Applications.

Chapter 1: Reliable, Scalable, and Maintainable Applications

Data Systems
- Dimensions to consider when thinking about data systems: access patterns, performance characteristics, implementations.
- Modern data systems often blur the lines between databases, caches, streams, etc.
Reliability
- Systems should perform the expected function at a given level of performance, and be tolerant to faults and user mistakes
Fault: One component of a system deviating from its spec. Prefer tolerating faults over preventing them (except for things like security issues). Faults stem from hardware failures, software failures, and human error (in a study, config errors caused most outages).

Identity Agent

C4Component
    title Identity Agent
    Container_Boundary(b1, "Identity Agent") {
        Container_Boundary(appdataB, "App Data") {
            Container(appdata, "App Data") 
            Rel(appdata, appDataStore, "use")

Store Entity Relation Diagram

erDiagram
    data_store_sequence {
        string table 
        number counter
    }
      event_log_sequence {
        string table

So you want to write a sync system for a web app with offline and realtime support? Good luck. You might find the following resources useful.

Overview articles

Database in a browser, a spec (Stepan Parunashvili)

What problem are we trying to solve with a sync system?
The web of tomorrow (Nikita Prokopov)

npm init -y
npm install @affinidi/wallet-node-sdk fetch@2 ts-node

ts-node revocable-vc.ts

	import Database from "libsql";

	const path = `${Date.now()}test-db.db`;
	const db = new Database(path);

	db.exec(`CREATE TABLE conversation (
	id varchar(36) primary key not null,
	startDate real,
	endDate real,
	summary text,

	{
	"name": "vector-test",
	"version": "1.0.0",
	"description": "",
	"type": "module",
	"main": "vec.js",
	"scripts": {
	"test": "echo \"Error: no test specified\" && exit 1"
	},
	"author": "",

	<!DOCTYPE html>
	<html>
	<head><meta charset="utf-8" />
	<meta http-equiv="X-UA-Compatible" content="chrome=1" />

	<meta name="apple-mobile-web-app-capable" content="yes" />
	<meta name="apple-mobile-web-app-status-bar-style" content="black-translucent" />


	<title>Verifiable presentation slides</title><script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.0.3/jquery.min.js"></script><script src="https://cdnjs.cloudflare.com/ajax/libs/require.js/2.1.10/require.min.js"></script>