Multi-level caching in HLD - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the first level cache type.

HLD

cache = [1]Cache()  # First level cache for fastest access

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ADatabase

BDisk

CInMemory

DNetwork

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing disk or database for first level cache.

The first level cache is usually an in-memory cache for fastest data retrieval.

2fill in blank

medium

Complete the code to define the second level cache type.

HLD

cache = [1]Cache()  # Second level cache for larger but slower storage

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AGPU

BInMemory

CCPU

DDisk

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing in-memory cache again or hardware components.

The second level cache is often disk-based to hold more data but slower than memory.

3fill in blank

hard

Fix the error in the cache eviction policy assignment.

HLD

cache.eviction_policy = '[1]'  # Set eviction policy to remove least recently used items

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ARandom

BLRU

CFIFO

DMRU

Attempts:

3 left

💡 Hint

Common Mistakes

Using FIFO or MRU which do not fit typical cache eviction.

LRU (Least Recently Used) is a common eviction policy for caches to remove old data.

4fill in blank

hard

Fill both blanks to complete the multi-level cache lookup logic.

HLD

if [1] in L1_cache:
    return L1_cache[[2]]

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Akey

Bvalue

Ccache

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'value' or 'item' which are not keys for lookup.

We check if the key is in the first level cache and return the value by the same key.

5fill in blank

hard

Fill all three blanks to complete the cache update after a miss.

HLD

if key not in L1_cache:
    data = [1].get(key)
    L2_cache.[2](key, data)
    L1_cache.[3](key, data)

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Adatabase

Bput

Cset

Dfetch

Attempts:

3 left

💡 Hint

Common Mistakes

Using fetch as a method on cache or wrong data source.

On a cache miss, data is fetched from the database, then stored in L2 and L1 caches using put and set methods respectively.