Rollback DANGEROUSLY_DISABLE_OOM (#14767)

Author: abhijithvijayan

docs/docs/scaling-issues.md

@@ -57,23 +57,6 @@ It's difficult to pin down exactly _how_ to fix a scaling issue. We have some re
 
 Note: the application of these techniques should be considered analogous to a applying a bandage. A bandage solves the underlying issue, but at some indeterminate point in the future the underlying issue may be healed! In much the same way--treat these techniques as temporary and re-visit in the future if underlying scaling issues in Gatsby have since been resolved.
 
-### `DANGEROUSLY_DISABLE_OOM`
-
-Gatsby's caching mechanism persists a (possibly!) large `json` file to disk _in memory._ To opt-out of this, consider something like:
-
-```json
-{
-  "devDependencies": {
-    "cross-env": "^5.2.0"
-  },
-  "scripts": {
-    "build": "cross-env DANGEROUSLY_DISABLE_OOM=true gatsby build"
-  }
-}
-```
-
-This will prevent caching, so it's recommended to only use this alongside the `gatsby build` command.
-
 ### `GATSBY_DB_NODES`
 
 In preparation for future versions of Gatsby, we've enabled **experimental** support for a different mechanism for the persistence of nodes: [Loki](https://www.npmjs.com/package/lokijs). It's challenging to assess whether this could lead to unforeseen issues without breaking changes, so we've exposed it behind a flag while we continue to assess the impact to Gatsby applications.

packages/gatsby/src/redux/__tests__/index.js

@@ -66,14 +66,4 @@ describe(`redux db`, () => {
     // yuck - loki and redux will have different shape of redux state (nodes and nodesByType)
     expect(_.omit(data, [`nodes`, `nodesByType`])).toMatchSnapshot()
   })
-
-  it(`does not write to the cache when DANGEROUSLY_DISABLE_OOM is set`, async () => {
-    process.env.DANGEROUSLY_DISABLE_OOM = true
-
-    await saveState()
-
-    expect(writeToCache).not.toBeCalled()
-
-    delete process.env.DANGEROUSLY_DISABLE_OOM
-  })
 })

packages/gatsby/src/redux/index.js

@@ -52,10 +52,6 @@ const store = configureStore(readState())
 
 // Persist state.
 const saveState = () => {
-  if (process.env.DANGEROUSLY_DISABLE_OOM) {
-    return Promise.resolve()
-  }
-
   const state = store.getState()
   const pickedState = _.pick(state, [
     `nodes`,