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  1. Moodle
  2. MDL-70368

Improve performance of get_imageinfo

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    • MOODLE_311_STABLE, MOODLE_401_STABLE
    • MOODLE_401_STABLE
    • MDL-70368-cache-image-metadata
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      This is a performance tracker so a before and after comparison is needed:

      Setup
      1. To simulate expensive latency due to a remote file system hack get_imageinfo_from_path in lib/filestorage/file_system.php and add a sleep(1) just before getimagesize().
      Before patch
      1. Navigate to any file picker such as /user/files.php and upload several images one by one
      2. Confirm as you upload each image loading the page will become progressively slower
      3. Reload the page
      4. You'll see that the page reloads slow (e.g. if you uploaded 3 images, it will take at least 3 seconds to load the page)
      After patch
      1. Apply the patch, purge caches
      2. Reload the page, the first reload will take a little longer
      3. Reload the page again and confirm the performance is back to being fast
      4. Add another image, confirm it is 1 second to load and then fast again on a reload
      Show
      This is a performance tracker so a before and after comparison is needed: Setup To simulate expensive latency due to a remote file system hack get_imageinfo_from_path in lib/filestorage/file_system.php and add a sleep(1) just before getimagesize() . Before patch Navigate to any file picker such as /user/files.php and upload several images one by one Confirm as you upload each image loading the page will become progressively slower Reload the page You'll see that the page reloads slow (e.g. if you uploaded 3 images, it will take at least 3 seconds to load the page) After patch Apply the patch, purge caches Reload the page, the first reload will take a little longer Reload the page again and confirm the performance is back to being fast Add another image, confirm it is 1 second to load and then fast again on a reload

      Getting image metadata from the File API pulls the file back down locally:

      https://github.com/moodle/moodle/blob/master/lib/filestorage/file_system.php#L382-L384

      In particular this gets used in a bunch of places when generating html to render an image tag with the right dimensions.

      This data almost never changes and this is all very inefficient. As this is used so often for thumbnails I'm proposing to make the width and height metadata fields directly in the mdl_files table

        1. after_patch_MDL-70368.mp4
          1.04 MB
        2. before_patch_MDL-70368.mp4
          2.34 MB
        3. image-2020-12-02-15-45-31-857.png
          image-2020-12-02-15-45-31-857.png
          34 kB

            brendanheywood Brendan Heywood
            brendanheywood Brendan Heywood
            Matthew Hilton Matthew Hilton
            Jun Pataleta Jun Pataleta
            John Edward Pedregosa John Edward Pedregosa
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