Show notice inviting users to use query on demand if their page query…

… running takes more than 2 minutes

packages/gatsby/src/services/run-page-queries.ts

@@ -2,6 +2,13 @@ import { processPageQueries } from "../query"
 import reporter from "gatsby-cli/lib/reporter"
 import { IQueryRunningContext } from "../state-machines/query-running/types"
 import { assertStore } from "../utils/assert-store"
+import {
+  showExperimentNoticeAfterTimeout,
+  CancelExperimentNoticeCallbackOrUndefined,
+} from "../utils/show-experiment-notice"
+import { isCI } from "gatsby-core-utils"
+
+const TWO_MINUTES = 2 * 60 * 1000
 
 export async function runPageQueries({
   parentSpan,
@@ -35,12 +42,38 @@ export async function runPageQueries({
   )
 
   activity.start()
+
+  let cancelNotice: CancelExperimentNoticeCallbackOrUndefined
+  if (
+    process.env.gatsby_executing_command === `develop` &&
+    !process.env.GATSBY_EXPERIMENTAL_QUERY_ON_DEMAND &&
+    !isCI()
+  ) {
+    cancelNotice = showExperimentNoticeAfterTimeout(
+      `queryOnDemand`,
+      reporter.stripIndent(`
+        We noticed that it takes more than two minutes to run your page queries. 
+        
+        Consider using experimental Query on Demand feature which would run queries
+        when resources for page are requested by browser instead of pre-running
+        all page queries eagerly. 
+        
+        See https://gatsby.dev/query-on-demand for details.
+      `),
+      TWO_MINUTES
+    )
+  }
+
   await processPageQueries(pageQueryIds, {
     state,
     activity,
     graphqlRunner,
     graphqlTracing: program?.graphqlTracing,
   })
 
+  if (cancelNotice) {
+    cancelNotice()
+  }
+
   activity.done()
 }