[shangyian]

Summary

Some GraphQL queries are expensive and identical across callers. This PR lets a deployment serve those responses from the shared cache.

What it does

• graphql_cacheable_operations lists operation names to cache. It is empty by default, which turns the feature off. Only named queries are eligible.
• The key is a hash of the operation name, the query and the variables. The query is parsed with graphql-core, so formatting doesn't change the key.
• Responses with errors aren't cached.

How it's invalidated

• Two version keys live in the cache: one for all data and one for availability. A cached response is stored under the current version, so changing the version invalidates the response cache.
• Availability has its own version because it is written thousands of times a day. It also only applies to queries that mention availability.
• A session listener replaces the version after the outermost commit of any write, including bulk statements.
• Cacheable queries read from the writer, so a lagging read replica can't cache old rows.
• Response caching is skipped, with a warning, when the cache is in-process.

Test Plan

• PR has an associated issue: #
• make check passes
• make test shows 100% unit test coverage

Deployment Plan

[netlify]

✅ Deploy Preview for thriving-cassata-78ae72 canceled.

Name	Link
🔨 Latest commit	d63a01e
🔍 Latest deploy log	https://app.netlify.com/projects/thriving-cassata-78ae72/deploys/6adcf34b6980f1adfb37dc52

[greptile-apps]

Confidence Score: 5/5

[Medium impact] The changes since the previous review appear safe to merge.

Summary

Adds opt-in caching for whole GraphQL responses.

• Opted-in GraphQL queries reuse responses until their data changes.

No new actionable issues were found in the changes since the previous review. The earlier threads were unnumbered, so they have no numbered classifications.

Diagram

%%{init: {'theme': 'neutral'}}%%
flowchart TD
  A[GraphQL POST] --> B{Allowed query and shared cache?}
  B -- No --> C[Run query normally]
  B -- Yes --> D[Choose writer and read data versions]
  D --> E{Cached response exists?}
  E -- Yes --> F[Return cached response]
  E -- No --> G[Run query against writer]
  G --> H{Successful response without errors?}
  H -- Yes --> I[Compress and cache response]
  H -- No --> J[Return without caching]
  K[Database write commits] --> L[Replace affected data versions]

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_{Reviews (6) · Last reviewed commit: "Give the fake requests in session tests ..." · Reviewed by Greptile}