Cache-aside (lazy loading) deep dive in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Cache-aside (lazy loading) pattern?

Cache-aside is a caching strategy where the application first checks the cache for data. If the data is missing (a cache miss), it loads the data from the database, stores it in the cache, and then returns it to the user.

beginner

Why is Cache-aside called 'lazy loading'?

Because data is only loaded into the cache when it is requested and not found there. This means the cache is filled on demand, not in advance.

beginner

What happens on a cache miss in Cache-aside pattern?

The application fetches the data from the database, writes it to the cache, and then returns the data to the user.

intermediate

How does Cache-aside handle data updates?

When data is updated in the database, the cache entry is usually invalidated or updated to keep cache and database consistent.

intermediate

What is a potential downside of Cache-aside pattern?

It can cause higher latency on the first request for data (cache miss), and if many requests miss simultaneously, it can overload the database (cache stampede).

In Cache-aside pattern, where is data loaded from when a cache miss occurs?

A From the client

B From the cache

C From a backup cache

D From the database

On a cache miss, the application loads data from the database before storing it in the cache.

What does Cache-aside pattern do when data is updated in the database?

A Automatically updates the cache without intervention

B Invalidates or updates the cache entry

C Ignores the cache

D Deletes the database record

To keep cache and database consistent, the cache entry is invalidated or updated after database changes.

Why might Cache-aside pattern cause a 'cache stampede'?

A Because many requests miss the cache simultaneously and hit the database

B Because cache is preloaded with too much data

C Because cache entries never expire

D Because the cache is too large

If many requests miss the cache at once, they all query the database, causing high load called a cache stampede.

Which of these best describes the Cache-aside pattern?

A Cache is loaded before any request

B Cache is updated only after data changes

C Cache is loaded on demand when data is requested

D Cache is never used

Cache-aside loads data into cache only when requested and missing, hence 'lazy loading'.

What is the first step in Cache-aside pattern when a user requests data?

A Check cache for data

B Update cache

C Fetch data from database

D Invalidate cache

The application first checks the cache to see if data is available before querying the database.

Explain how the Cache-aside (lazy loading) pattern works step-by-step when a user requests data.

Think about what happens when data is not found in cache.

Describe how Cache-aside pattern handles data updates to keep cache and database consistent.

Consider what must happen after changing data in the database.