[Solved] You design a system where multiple threads read and write a shared cache.... Which concurrency control mechanism fits best? | LLD

LLD - Design — Parking Lot System

You design a system where multiple threads read and write a shared cache. To improve performance, you want to allow multiple readers but only one writer at a time. Which concurrency control mechanism fits best?

AUse a read-write lock allowing concurrent reads but exclusive writes

BUse a simple mutex lock for all access

CUse no locks and rely on thread scheduling

DUse a semaphore with count 1 for all operations

Step-by-Step Solution

Solution:

Step 1: Understand concurrency needs for readers and writers
Multiple readers can safely access shared data simultaneously, but writers need exclusive access to avoid conflicts.
Step 2: Choose appropriate lock type
A read-write lock allows many readers at once but only one writer, balancing concurrency and safety efficiently.
Final Answer:
Use a read-write lock allowing concurrent reads but exclusive writes -> Option A
Quick Check:
Read-write lock fits multiple readers, single writer = B [OK]

Quick Trick: Read-write locks allow many readers, one writer [OK]

Common Mistakes:

MISTAKES

Using simple mutex reduces concurrency
Ignoring need for exclusive write access
Relying on no locks causes data races

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More LLD Quizzes

Which concurrency control mechanism fits best?

Step 1: Understand concurrency needs for readers and writers

Step 2: Choose appropriate lock type

Final Answer:

Quick Check:

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