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Lessons (40)
- AWS Data Pipelines in Plain Language
Move raw data into S3, clean it, catalogue it, and query it without learning every analytics service at …
- Cross-Service Data: How to Join Without a Database JOIN
When Order Service and User Service own separate databases, learn how to compose APIs, replicate data and build …
- Big Data: ETL, Warehouses and Streaming
… ETL extracts, transforms and loads curated data. A data lake holds raw/flexible data; a warehouse optimizes governed …
- Storage Engines & Database Operations
Understand B-trees, LSM trees, write-ahead logs, connection pools, backups and the signals behind database reliability. What …
- 10,000 Users Do Not Need 10,000 Database Connections
A practical mental model for connection pools, database pressure, query latency and safe scaling in Node.js applications …
- SQL vs NoSQL Databases
Relational tables or flexible documents? Understand how each stores data, the four NoSQL families, ACID vs BASE, and …
- AWS Databases: Choose the Right One
… managed SQL database RDS runs engines such as PostgreSQL and MySQL while AWS handles hardware, backups, and many …
- Data Preparation and Model Training
Turn raw data into trustworthy examples, prevent leakage, and build repeatable training experiments. The big idea Model quality …
- Caching & Redis
Keep frequently used data close and fast. Learn caching strategies, invalidation, eviction policies, the classic pitfalls, and what …
- Data in Microservices: Sagas & the Outbox Pattern
Each service owns its database, so how do you keep data consistent across services without a shared transaction …
- SQL Language, Identifiers & Data Types
… DML reads/changes data: SELECT, INSERT, UPDATE and DELETE. DCL manages permissions: GRANT and REVOKE. Many systems call …
- Database Relations & Foreign Keys
Model one-to-one, one-to-many and many-to-many data with keys, constraints and deletion rules …
- Database Internals, Replication and Scaling
Connect storage-engine choices, durability, replicas, query plans, pooling and data layout to real production behaviour. The problem …
- Dependencies, Data Sources, and Resource Lifecycle
… Broad module-level dependencies can cause more unknown values and more conservative plans. Read versus own hcl data …
- Batch vs Stream and Data Modeling
Choose when work runs and shape data for correctness first, then deliberately denormalize proven read bottlenecks. The problem …
- VPC Networking Without the Confusion
… A PostgreSQL authentication error shows that the client reached a database process; investigate credentials and database privileges next …
- Data Structures for Scale
… spatial indexes locate nearby items; probabilistic sketches answer large-set questions cheaply](/img/system-design-l6/scale-data …
- Kafka vs RabbitMQ & the Kafka Ecosystem
… databases (Debezium CDC), S3, MQTT, Salesforce. - Sink connectors push data out : Elasticsearch, S3, Snowflake, BigQuery, MongoDB, Postgres. json …
- Caching, Consistent Hashing and Sharding
Move reads close to users, distribute data safely, and understand cache and database consistency costs. The problem in …
- DynamoDB Modeling, RDS Scaling and Data Resilience
Design DynamoDB tables around access patterns, then scale and protect relational databases with replicas, proxies and Multi-AZ …
- AWS: Start Here
… you can rent a server, database, file storage, network, or message queue in minutes. Where AWS runs your …
- Storage, Search and Location Queries
Use the right data system for files, text search and nearby-place queries instead of forcing every need …
- Backend Design Scenarios
Ten production-style backend questions about caching, data growth, scaling, reliability and system design, with structured answers and …
- EC2, Storage and Auto Scaling
… Further reading: [EC2 user data](https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/user-data.html), [Auto Scaling …
- Resilience, Disaster Recovery and Multi-Region Design
… Multi-AZ does not recover logically corrupted data. The four DR strategies mermaid flowchart LR A[Backup and …
- Indexes, EXPLAIN & Query Plans
… The cost is extra disk, memory, write work and maintenance. ![An index lets the database seek to matching …
- Layered (N-Tier) Architecture
The classic way to organise an application into presentation, business and data layers. How it works, its rules …
- StatefulSets, DaemonSets, Jobs and CronJobs
… data mountPath: /var/lib/postgresql/data volumeClaimTemplates: - metadata: name: data spec: accessModes: [ReadWriteOnce] resources: requests: storage: 20Gi Key …
- Multi-Region and Disaster Recovery
Decide what must survive a regional failure, how much data can be lost, and how recovery is actually …
- Replication, Partitioning & Sharding
Scale reads with replicas, split data safely with partitions and shards, and plan for consistency, hot keys and …
- Configuration, Secrets and Storage
Keep settings out of images, keep sensitive values protected, and keep important data when a pod is replaced …
- State Management (Redux, Zustand, TanStack Query)
Where should data live in a frontend app? Learn the four kinds of state, when local state is …
- Edge, Platform & Frontend Delivery
… Personal or frequently changing data usually needs a server boundary. Do not put database credentials or heavy, long …
- Transactions, Indexes & Concurrency
… state the database product you mean. Q11: Livelock versus deadlock Deadlock is circular waiting, so the database aborts …
- Database Indexing & Transactions
… A database index works the same way. ![Without an index the database scans every row; with one it …
- MVC, MVP & MVVM
Three patterns for separating what the user sees from the data and logic behind it. How each works …
- Next.js Rendering: CSR, SSR, SSG, ISR & Server Components
… fetch data DB-- S: data S-- B: ✅ full HTML (visible immediately) B- B: download JS → hydrate → interactive ✅ Fast …
- What to Learn in AI, and in What Order
A practical map from programming and data basics through machine learning, deep learning, LLM applications, evaluation, and production …
- Cost Optimization and the Well-Architected Framework
… 7 } }] } Databases - Use Aurora Serverless v2 or schedule stop for dev databases; delete old manual snapshots. - DynamoDB: pick …
- Code Profiling
… Add timings around the database query and any external calls next; do not log private order data just …