fix(gatsby): wait for LMDB upserts to finish before emitting ENGINES_…

…READY (#34853) (#34896)

(cherry picked from commit b4637c0)

Co-authored-by: Michal Piechowiak <misiek.piechowiak@gmail.com>

packages/gatsby/src/commands/build.ts

@@ -286,6 +286,9 @@ module.exports = async function build(
     )
   }
 
+  // Start saving page.mode in the main process (while queries run in workers in parallel)
+  const waitMaterializePageMode = materializePageMode()
+
   let waitForWorkerPoolRestart = Promise.resolve()
   if (process.env.GATSBY_EXPERIMENTAL_PARALLEL_QUERY_RUNNING) {
     await runQueriesInWorkersQueue(workerPool, queryIds, {
@@ -322,6 +325,7 @@ module.exports = async function build(
   }
 
   if (process.send && shouldGenerateEngines()) {
+    await waitMaterializePageMode
     process.send({
       type: `LOG_ACTION`,
       action: {
@@ -401,9 +405,6 @@ module.exports = async function build(
 
   await waitForWorkerPoolRestart
 
-  // Start saving page.mode in the main process (while HTML is generated in workers in parallel)
-  const waitMaterializePageMode = materializePageMode()
-
   const { toRegenerate, toDelete } =
     await buildHTMLPagesAndDeleteStaleArtifacts({
       program,

packages/gatsby/src/utils/page-mode.ts

@@ -8,6 +8,7 @@ import {
 import { reportOnce } from "./report-once"
 import { ROUTES_DIRECTORY } from "../constants"
 import { Runner } from "../bootstrap/create-graphql-runner"
+import { getDataStore } from "../datastore"
 
 type IPageConfigFn = (arg: { params: Record<string, unknown> }) => {
   defer: boolean
@@ -111,6 +112,7 @@ export async function materializePageMode(): Promise<void> {
       await new Promise(resolve => setImmediate(resolve))
     }
   }
+  await getDataStore().ready()
 }
 
 export async function preparePageTemplateConfigs(