Response caching strategies in GraphQL - Step-by-Step Execution

Concept Flow - Response caching strategies

Client sends GraphQL query

↓

Check cache for query response

↓

Return cached

↓

Send response

↓

Client receives response

The flow shows how a GraphQL server checks if a query response is cached before running resolvers, returning cached data if available, or executing and caching the response if not.

Execution Sample

GraphQL

query GetUser {
  user(id: "1") {
    id
    name
  }
}

A client requests user data by ID; the server checks cache before resolving.

Execution Table

Step	Action	Cache Hit?	Cache Store	Response Sent
1	Receive query GetUser with id=1	No	No	No
2	Check cache for query response	No	No	No
3	Execute resolver to fetch user data	No	No	No
4	Store response {id:1, name:'Alice'} in cache	No	Yes	No
5	Send response to client	No	Yes	Yes
6	Receive same query again	Yes	Yes	No
7	Return cached response	Yes	Yes	Yes

💡 Execution stops after sending response to client.

Variable Tracker

Variable	Start	After Step 2	After Step 4	After Step 7
cache	{}	{}	{"GetUser(id:1)": {"id": "1", "name": "Alice"}}	{"GetUser(id:1)": {"id": "1", "name": "Alice"}}
responseSent	false	false	false	true

Key Moments - 3 Insights

Why does the server check the cache before executing the resolver?

Checking the cache first avoids unnecessary resolver execution, saving time and resources, as shown in execution_table step 2 where cache is checked before running the resolver.

What happens if the cache does not have the response?

The server executes the resolver to get fresh data, then stores it in the cache for future use, as seen in steps 3 and 4.

How does the server know when to send the cached response?

If the cache has the response (cache hit), the server sends it immediately without running resolvers, as shown in step 7.

Visual Quiz - 3 Questions

Look at the execution_table, at which step is the response stored in the cache?

A Step 4

B Step 2

C Step 6

D Step 7

💡 Hint

Check the 'Cache Store' column in execution_table rows.

At which step does the server send the cached response to the client?

A Step 3

B Step 7

C Step 5

D Step 1

💡 Hint

Look at the 'Cache Hit?' and 'Response Sent' columns in execution_table.

If the cache was empty, what would happen at step 2?

A Cache hit, return cached response

B Send error response

C Cache miss, execute resolver

D Ignore query

💡 Hint

Refer to the 'Cache Hit?' column and subsequent actions in execution_table.

Concept Snapshot

Response caching in GraphQL:
- Check cache before running resolvers
- If cache hit, return cached response immediately
- If cache miss, execute resolver and store response
- Improves performance by reducing resolver calls
- Cache keys often based on query and variables

Full Transcript

This visual execution shows how a GraphQL server handles response caching. When a client sends a query, the server first checks if the response is already cached. If yes, it returns the cached response immediately, saving time. If not, it runs the resolver to get fresh data, stores this response in the cache, then sends it to the client. Variables like 'cache' track stored responses, and 'responseSent' tracks if the client got the data. Key moments include understanding why cache is checked first, what happens on cache miss, and how cached responses are returned. The quiz questions help reinforce these steps by referencing the execution table and variable states.