Abstract Algorithms

concurrency

2 articles across 2 sub-topics

LLD for Movie Booking System: Designing BookMyShow

TLDR TLDR: A Movie Booking System (like BookMyShow) is an inventory management problem with an expiry: seats expire when the show starts. The core engineering challenge is preventing double-booking under concurrent user load with a 3-state seat mode...

Mar 9, 2026•22 min read

Database(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