Caching Strategies

There are several caching strategies:

• Refresh Ahead
• Write-Behind
• Write-through
• Cache Aside

Refresh Ahead

Example: Product catalog pages, trending news feeds, session metadata, or dashboard widgets.

sequenceDiagram
    participant Client
    participant Cache
    participant Source as Data Source

    Client->>Cache: Read data
    Cache-->>Client: Return cached data
    Note over Cache: Entry is close to expiring
    Cache->>Source: Refresh in background
    Source-->>Cache: Return current data
    Cache->>Cache: Replace cached entry

Write-Behind

Example: Logging, analytics event ingestion, like counters, activity tracking, or telemetry buffers.

sequenceDiagram
    participant Client
    participant Cache
    participant Source as Data Source

    Client->>Cache: Write data
    Cache-->>Client: Acknowledge immediately
    Note over Cache,Source: Asynchronous write
    Cache->>Source: Persist queued update
    Source-->>Cache: Confirm persistence

Write-Through

Example: User profiles, inventory counts, banking balances, order status.

sequenceDiagram
    participant Client
    participant Cache
    participant Source as Data Source

    Client->>Cache: Write data
    Cache->>Source: Persist data
    Source-->>Cache: Confirm persistence
    Cache->>Cache: Update cached entry
    Cache-->>Client: Acknowledge write

Cache Aside

Example: User profiles, blog posts, configuration data, search results, or API responses.

sequenceDiagram
    participant Client
    participant App as Application
    participant Cache
    participant Source as Data Source

    Client->>App: Request data
    App->>Cache: Look up data
    alt Cache hit
        Cache-->>App: Return cached data
    else Cache miss
        Cache-->>App: Not found
        App->>Source: Query data
        Source-->>App: Return data
        App->>Cache: Store data
    end
    App-->>Client: Return data