Unable to notice any difference in subsequent build times using incremental build approach

Hi team, I’m facing issue using the new incremental build feature, I’ve set the GATSBY_EXPERIMENTAL_PAGE_BUILD_ON_DATA_CHANGES=true in .env file And then gatsby build I don’t see any time difference among the subsequent builds even while not updating any file, content, or be it a data source Using it in POWERSHELL, $env:GATSBY_EXPERIMENTAL_PAGE_BUILD_ON_DATA_CHANGES="true"; gatsby build , it still takes the same time as it does during the initial build Incremental builds are supposed to reduce build times, right? Am I using it in the wrong way? Need help configuring the incremental build flag, the build time on every small update is very costly as of now Current build time: 420 seconds

System

Windows 10 Pro VScode terminal (PowerShell) node -v: v12.16.2 npm -v: 6.14.4

package.json

{
  "name": "gatsby-starter-default",
  "private": true,
  "description": "A simple starter to get up and developing quickly with Gatsby",
  "version": "0.1.0",
  "author": "Kyle Mathews <[e-mail]>",
  "dependencies": {
    "@mdx-js/mdx": "^1.5.8",
    "@mdx-js/react": "^1.5.8",
    "axios": "^0.19.2",
    "dotenv": "^8.2.0",
    "gatsby": "^2.19.45",
    "gatsby-image": "^2.2.44",
    "gatsby-plugin-catch-links": "^2.2.1",
    "gatsby-plugin-manifest": "^2.2.48",
    "gatsby-plugin-mdx": "^1.1.4",
    "gatsby-plugin-offline": "^3.0.41",
    "gatsby-plugin-react-helmet": "^3.1.24",
    "gatsby-plugin-sass": "^2.2.1",
    "gatsby-plugin-sharp": "^2.4.13",
    "gatsby-source-filesystem": "^2.2.2",
    "gatsby-source-git": "^1.0.2",
    "gatsby-source-mongodb": "^2.2.1",
    "gatsby-transformer-remark": "^2.7.1",
    "gatsby-transformer-sharp": "^2.3.19",
    "http-server": "^0.12.1",
    "monaco-editor": "^0.20.0",
    "monaco-editor-webpack-plugin": "^1.9.0",
    "node-sass": "^4.13.1",
    "prop-types": "^15.7.2",
    "react": "^16.12.0",
    "react-dom": "^16.12.0",
    "react-helmet": "^5.2.1",
    "react-monaco-editor": "^0.35.0"
  },
  "devDependencies": {
    "prettier": "^1.19.1"
  },
  "keywords": [
    "gatsby"
  ],
  "license": "MIT",
  "scripts": {
    "build": "npm run clean && gatsby build",
    "develop": "gatsby develop",
    "format": "prettier --write \"**/*.{js,jsx,json,md}\"",
    "start": "npm run clean && npm run develop",
    "serve": "npm run clean && gatsby build && gatsby serve",
    "clean": "gatsby clean",
    "test": "echo \"Write tests! -> https://gatsby.dev/unit-testing\" && exit 1"
  },
  "repository": {
    "type": "git",
    "url": "https://github.com/gatsbyjs/gatsby-starter-default"
  },
  "bugs": {
    "url": "https://github.com/gatsbyjs/gatsby/issues"
  }
}

[StuartRayson]

@ascorbic 👋

Might be worth updating the documentation for the usage of GATSBY_EXPERIMENTAL_PAGE_BUILD_ON_DATA_CHANGES to make it clear that this is not the same solution to Gatsby Cloud incremental build.

As i’ve seen another issue where users are expecting the same build times as Gatsby Cloud using just this environment variable. https://github.com/gatsbyjs/gatsby/issues/23531

i’m happy to do this?

[ascorbic]

I think the confusion here is that GATSBY_EXPERIMENTAL_PAGE_BUILD_ON_DATA_CHANGES=true is a different thing from the incremental builds on Gatsby Cloud, so you shouldn’t expect the same results. As @StuartRayson points out, page building is only one part of the build that can take a long time, so unfortunately even if that is quicker you won’t be able to get sub 10-second builds like on Gatsby Cloud. (FWIW, you don’t need an Enterpise account to get them.)