Abstract Algorithms

database

2 articles across 2 sub-topics

LLD for URL Shortener: Designing TinyURL

TLDR TLDR: A URL Shortener maps long URLs to short IDs. The core challenge is generating a globally unique, short, collision-free ID at scale. We use Base62 encoding on auto-incrementing database IDs for deterministic, collision-free short codes. ...

Mar 9, 2026•21 min read

Concurrency(1)

Types of Locks Explained: Optimistic vs. Pessimistic Locking

TLDR: Pessimistic locking locks the record before editing — safe but slower under low contention. Optimistic locking checks for changes before saving using a version number — fast but can fail and require retry under high contention. Choosing correct...

Feb 10, 2026•13 min read