Query depth and complexity in GraphQL - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is query depth in GraphQL?

Query depth is the number of nested levels in a GraphQL query. It shows how deep the query goes into related data.

beginner

Why do we limit query depth in GraphQL?

Limiting query depth helps prevent very deep queries that can slow down the server or cause crashes by using too many resources.

intermediate

What does query complexity mean in GraphQL?

Query complexity measures how expensive a query is to run, based on factors like number of fields, nested levels, and custom weights for fields.

intermediate

How can you control query complexity in GraphQL?

You can assign costs to fields and calculate total cost of a query. Then reject queries that exceed a set complexity limit to protect the server.

beginner

Give an example of a simple GraphQL query with depth 2.

Example: { user { name posts { title } } } has depth 3 because 'posts' is nested inside 'user', and 'title' is nested inside 'posts'.

What does query depth measure in GraphQL?

A Number of nested levels in a query

B Number of fields in a query

C Size of the response data

D Number of queries sent

Query depth counts how many levels of nested fields the query has.

Why limit query complexity in GraphQL?

A To increase query speed always

B To reduce network traffic

C To prevent slow or crashing servers

D To allow unlimited queries

Limiting complexity protects the server from expensive queries that use too many resources.

Which of these increases query complexity?

A More nested fields

B Fewer fields

C Shallow queries

D No nested fields

More nested fields mean more work for the server, increasing complexity.

What happens if a query exceeds the allowed depth limit?

A The query runs slower but succeeds

B The server rejects the query

C The query runs faster

D The server ignores the limit

Servers usually reject queries that are too deep to protect resources.

Which is a good practice to manage query complexity?

A Only limit query length

B Allow unlimited nested queries

C Ignore query size

D Assign cost values to fields

Assigning costs helps calculate total complexity and reject expensive queries.

Explain what query depth and query complexity mean in GraphQL and why they matter.

Think about how deep queries can get and how much work they cause.

Describe how you would protect a GraphQL server from very expensive queries.

Consider limits and cost calculations.