gatsby: Build gets stuck at Generating image thumbnails / Update schema on large sites

I am querying allImageSharp in a project with 300 pages and 2000 images in gatsby-node. During gatsby build or gatsby develop, the build process freezes when generating thumbnail 20~ or so

Generating image thumbnails [==----------------------------] 25/9667 24.0 secs 0%

I also have the same query called in a static query on a page. If I remove the query from gatsby-node and use only the one in the page, the thumbnails generation correctly in around 600 seconds

Generating image thumbnails [=============================-] 9235/9667 560.0 secs 96%

This is what my query looks like:

gallery: allImageSharp {
  edges {
    node {
      fluid(
        sizes: "(orientation: portrait) 50vw, (orientation: portrait) and (min-width: 750px) 30vw, (orientation: landscape) 30vw,(orientation: landscape) and (min-width: 1170px) 18vw,(orientation: landscape) and (min-width: 1800px) 16vw"
      ) {
        aspectRatio
        base64
        presentationHeight
        presentationWidth
        sizes
        src
        srcSet
      }
    }
  }
}

Environment

System:
    OS: macOS 10.14.4
    CPU: (4) x64 Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz
    Shell: 3.2.57 - /bin/bash
  Binaries:
    Node: 10.15.3 - ~/.nvm/versions/node/v10.15.3/bin/node
    Yarn: 1.15.2 - /usr/local/bin/yarn
    npm: 6.9.0 - ~/.nvm/versions/node/v10.15.3/bin/npm
  Languages:
    Python: 2.7.15 - /usr/local/bin/python
  npmPackages:
    gatsby: ^2.4.5 => 2.4.5
    gatsby-image: ^2.0.41 => 2.0.41
    gatsby-plugin-algolia: ^0.3.0 => 0.3.0
    gatsby-plugin-intl: ^0.1.7 => 0.1.7
    gatsby-plugin-manifest: ^2.1.1 => 2.1.1
    gatsby-plugin-matomo: ^0.7.0 => 0.7.0
    gatsby-plugin-offline: ^2.1.0 => 2.1.0
    gatsby-plugin-react-helmet: ^3.0.12 => 3.0.12
    gatsby-plugin-robots-txt: ^1.4.0 => 1.4.0
    gatsby-plugin-sass: ^2.0.11 => 2.0.11
    gatsby-plugin-sharp: ^2.0.37 => 2.0.37
    gatsby-plugin-sitemap: ^2.1.0 => 2.1.0
    gatsby-plugin-typescript: ^2.0.13 => 2.0.13
    gatsby-remark-images: ^3.0.11 => 3.0.11
    gatsby-source-filesystem: ^2.0.34 => 2.0.34
    gatsby-transformer-json: ^2.1.11 => 2.1.11
    gatsby-transformer-remark: ^2.3.12 => 2.3.12
    gatsby-transformer-sharp: ^2.1.19 => 2.1.19
  npmGlobalPackages:
    gatsby-cli: 2.5.14