System Design

⏱ 7 min read Deleting data is irreversible by default. Soft delete marks records as deleted without removing them from the database; hard delete […] Read article

⏱ 6 min read The thundering herd problem occurs when many processes or threads simultaneously wake up to compete for the same scarce resource Read article

⏱ 6 min read Pagination enables clients to retrieve large result sets page by page instead of in one response. Two primary approaches exist: Read article

⏱ 4 min read Database indexes dramatically accelerate query performance by providing direct access paths to rows, avoiding full table scans. However, indexes consume Read article

⏱ 6 min read The Write-Ahead Log (WAL) is the foundation of database durability and crash recovery. Every change to database state is first Read article

⏱ 6 min read CRDTs (Conflict-Free Replicated Data Types) are data structures that can be updated independently and concurrently on multiple nodes without coordination, Read article

⏱ 6 min read OAuth2 is an authorization framework that allows users to grant third-party applications limited access to their accounts without sharing passwords. Read article

⏱ 4 min read Multi-Version Concurrency Control (MVCC) is the concurrency mechanism used by PostgreSQL, MySQL InnoDB, Oracle, and most modern databases to enable Read article

⏱ 6 min read GraphQL is a query language for APIs where clients specify exactly the data they need and receive nothing more. Unlike Read article

⏱ 6 min read WebSocket provides full-duplex, low-latency communication between a browser and server over a single persistent TCP connection. Unlike HTTP polling (client Read article

⏱ 4 min read Geo-spatial indexing enables efficient queries on geographic data: finding restaurants within 1km, matching drivers to riders within 500m, showing events Read article

⏱ 6 min read Full-text search finds documents matching natural language queries across large corpora. Unlike exact-match database queries (WHERE name = ‘foo’), full-text Read article

⏱ 5 min read An audit log records a tamper-evident, chronologically ordered history of all significant actions in a system: who did what, when, Read article

⏱ 3 min read gRPC is a high-performance RPC framework built on HTTP/2 and Protocol Buffers. It provides strongly-typed service contracts, efficient binary serialization, Read article

⏱ 5 min read A real-time leaderboard ranks users or entities by a score that updates continuously. The core challenge is serving low-latency rank Read article