While Pokémon GO and Netflix are fun apps, they can also be huge data drains when not on WiFi. Google Play is investing in improvements to reduce the data that needs to be transferred for app installs and updates, while making data costs more transparent to users. Google recently rolled out a new delta algorithm “bsdiff” that reduces patches by 50% or more.
In the past when one updated an app, they would essentially have to redownload the app and the large amount of data that accompanied it. Since 2012, only changes or deltas to APK files have been downloaded and merged with the existing files. Google has since been doing version checks of apps, and then sends out a patch that merges the changes the developer made with the files the user already has for the app.
The bsdiff algorithm specifically takes advantage of the ways in which compiled native code changes between versions. Native libraries should be stored uncompressed to be most effective since compression interferes with the delta algorithm. Apps that are compressed, however, can still potentially see a 5% decrease in data usage.
APK Expansion Files allow users to include files up to 2GB in size. This is especially useful for games which often demand high resolution graphics or large media files. Bsdiff reduces the download size of initial installations by 12% and updates by 65%.
Google has also made information about data usage and download sizes clearer in the Play Store. Users can now see the actual download size, not just the APK file size. If the user already has downloaded an app, they will only see the update size.
Users should still be careful to not go hog wild with their data usage. If you need to install something large, it is probably best to stick to Wifi. It is still nice to see however, Google working hard to reduce customer’s data usage.