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> Facebook and other services do not actually delete data, they just mark it as "deleted" and purge it only if they need the space. You may be correct, but tha

> Facebook and other services do not actually delete data, they just mark it as "deleted" and purge it only if they need the space. You may be correct, but that doesn't explain why Facebook decided to include so-called deleted files in a download of user data. Clearly these deleted files are still a part of Facebook user profiles and accessible to company data mining software. Facebook has exposed their own duplicity.

2muchcoffeeman 9y ago
Maybe the Facebook development processes and tracking of tech debt is just shit. First person: "I'll just flag the content and then it won't show on their timeline!" Second person: "I'll just select all the records that belongs to this account when packaging a backup. All the deleted content should be gone!" But I wouldn't discount your hypothesis.
- pishpash 9y ago
  When storage is cheap, it's rational to develop the delete flag first and think about cleanup later, which means never. The download content thing seems like a low priority project and the poor intern who probably did it didn't want to figure out how each store keeps the delete flag. At least it's honest. Would you be surprised a dd of your sd card showed your deleted photos?
  - paulie_a 9y ago
    Storage being cheap is irrelevant..when a user requests the data to be deleted. You delete it. Outside of government compliance there is no reason to not comply with that request
    - sgtmas2006 9y ago
      Yes there are, but there are no moral reasons to not comply with it.
      - scottmf 9y ago
        Why, to help people connect better of course...
        vidarh 9y ago
        There might be something to that, in the sense that I could very well see someone in a meeting ask 'well, but what do we do when another user is tagged in a photo' followed by discussion rationalising why that person shouldn't lose out because someone wants to delete data, and someone coming up with the 'solution' of effectively reference counting the data and figuring out when to actually purge the underlying file later (i.e. never)
      - pbhjpbhj 9y ago
        If your ethics are such that you believe the state should be able to view data on someone in order to help prosecution of a crime then you could support the retention of data on all users in order to avoid deletions made to hide criminal activity. Such an ethic creates a moral reasoning to not comply with an individual's wishes in the immediate deletion of data. (FWIW I'm not defending this position nor suggesting it's the case here, just you said there's no moral reason that can support it, which seems wrong; different ethical systems can provide different reasoned moral outcomes.)
    - kbsletten 9y ago
      That's not true. What if you want to support un-delete? That's a reason.
      - scottmf 9y ago
        To my knowledge there is and has never been any option to “undelete” your deleted content on Facebook.
        delfb 9y ago
        Mm, what about deactivated accounts? You can reactivate them, which would involve undeleting data.
        robryk 9y ago
        I'd be surprised if there wasn't at least a way to deal with large-scale account hijacking, where the hijacker deleted lots of hijacked accounts' content.
    - bigiain 9y ago
      <cynical view> When a _customer_ requests data to be deleted, you delete it. Pretty sure Facebook have probably complied with every user-data-deletion request they've ever got from their paying customers - because advertisers are well know for wanting access to less data about the cattle...
      - dx034 9y ago
        I doubt that advertisers requesting to have all their information deleted (apart from tax relevant data) would be more successful.
      - paulie_a 9y ago
        Fuck their paying customers
- mistermann 9y ago
  Maybe they should get someone from the internal department that monitors Facebook employees to come over and show them how to run a tight ship: https://www.theguardian.com/technology/2018/mar/16/silicon-valley-internal-work-spying-surveillance-leakers https://www.theguardian.com/technology/2018/mar/16/silicon-v...
dboreham 9y ago
>Facebook has exposed their own duplicity. Or possibly they just screwed up. Perhaps the "soft delete" was originally intended to allow "undelete" by the user with delayed purge, and/or single-instance storage with reference counting that they never quite got around to finishing.
pwg 9y ago
> but that doesn't explain why Facebook decided to include so-called deleted files in a download of user data. This happened because the person tasked with writing the code to build the archive forgot to include the filter for "deleted" records somewhere in the code. I.e., they forgot the "where is_deleted = false" part below on one or more DB query requests like this: select * from table where is_deleted = false; This is the biggest problem with the "soft delete flag in database" method of deletion. Every single query writer, everywhere, forever, must always remember to include the "is_deleted" filter in their queries. And when they don't, what was deleted reappears as if it had never been deleted at all.
- astrange 9y ago
  If you have soft-deleted user data, then you have user data, so you had better include it.
  - gnu8 9y ago
    That is a good point, but flagging shouldn’t be the end of the line for soft deleted data. There should be a process going back and removing everything that was flagged for deletion, prioritized to guarantee deletion within a set time frame but without impacting performance. Meanwhile, most queries should be done through a view that automatically masks out any flagged data. It’s a basic data integrity feature that shouldn’t be left to their API (which is such a fast moving target that one developer doesn’t know what the other is doing much of the time).

2muchcoffeeman 9y ago

Maybe the Facebook development processes and tracking of tech debt is just shit. First person: "I'll just flag the content and then it won't show on their timeline!" Second person: "I'll just select all the records that belongs to this account when packaging a backup. All the deleted content should be gone!" But I wouldn't discount your hypothesis.

pishpash 9y ago
When storage is cheap, it's rational to develop the delete flag first and think about cleanup later, which means never. The download content thing seems like a low priority project and the poor intern who probably did it didn't want to figure out how each store keeps the delete flag. At least it's honest. Would you be surprised a dd of your sd card showed your deleted photos?
- paulie_a 9y ago
  Storage being cheap is irrelevant..when a user requests the data to be deleted. You delete it. Outside of government compliance there is no reason to not comply with that request
  - sgtmas2006 9y ago
    Yes there are, but there are no moral reasons to not comply with it.
    - scottmf 9y ago
      Why, to help people connect better of course...
      - vidarh 9y ago
        There might be something to that, in the sense that I could very well see someone in a meeting ask 'well, but what do we do when another user is tagged in a photo' followed by discussion rationalising why that person shouldn't lose out because someone wants to delete data, and someone coming up with the 'solution' of effectively reference counting the data and figuring out when to actually purge the underlying file later (i.e. never)
    - pbhjpbhj 9y ago
      If your ethics are such that you believe the state should be able to view data on someone in order to help prosecution of a crime then you could support the retention of data on all users in order to avoid deletions made to hide criminal activity. Such an ethic creates a moral reasoning to not comply with an individual's wishes in the immediate deletion of data. (FWIW I'm not defending this position nor suggesting it's the case here, just you said there's no moral reason that can support it, which seems wrong; different ethical systems can provide different reasoned moral outcomes.)
  - kbsletten 9y ago
    That's not true. What if you want to support un-delete? That's a reason.
    - scottmf 9y ago
      To my knowledge there is and has never been any option to “undelete” your deleted content on Facebook.
      - delfb 9y ago
        Mm, what about deactivated accounts? You can reactivate them, which would involve undeleting data.
      - robryk 9y ago
        I'd be surprised if there wasn't at least a way to deal with large-scale account hijacking, where the hijacker deleted lots of hijacked accounts' content.
  - bigiain 9y ago
    <cynical view> When a _customer_ requests data to be deleted, you delete it. Pretty sure Facebook have probably complied with every user-data-deletion request they've ever got from their paying customers - because advertisers are well know for wanting access to less data about the cattle...
    - dx034 9y ago
      I doubt that advertisers requesting to have all their information deleted (apart from tax relevant data) would be more successful.
    - paulie_a 9y ago
      Fuck their paying customers
mistermann 9y ago
Maybe they should get someone from the internal department that monitors Facebook employees to come over and show them how to run a tight ship: https://www.theguardian.com/technology/2018/mar/16/silicon-valley-internal-work-spying-surveillance-leakers https://www.theguardian.com/technology/2018/mar/16/silicon-v...

dboreham 9y ago

>Facebook has exposed their own duplicity. Or possibly they just screwed up. Perhaps the "soft delete" was originally intended to allow "undelete" by the user with delayed purge, and/or single-instance storage with reference counting that they never quite got around to finishing.

pwg 9y ago

> but that doesn't explain why Facebook decided to include so-called deleted files in a download of user data. This happened because the person tasked with writing the code to build the archive forgot to include the filter for "deleted" records somewhere in the code. I.e., they forgot the "where is_deleted = false" part below on one or more DB query requests like this: select * from table where is_deleted = false; This is the biggest problem with the "soft delete flag in database" method of deletion. Every single query writer, everywhere, forever, must always remember to include the "is_deleted" filter in their queries. And when they don't, what was deleted reappears as if it had never been deleted at all.

astrange 9y ago
If you have soft-deleted user data, then you have user data, so you had better include it.
- gnu8 9y ago
  That is a good point, but flagging shouldn’t be the end of the line for soft deleted data. There should be a process going back and removing everything that was flagged for deletion, prioritized to guarantee deletion within a set time frame but without impacting performance. Meanwhile, most queries should be done through a view that automatically masks out any flagged data. It’s a basic data integrity feature that shouldn’t be left to their API (which is such a fast moving target that one developer doesn’t know what the other is doing much of the time).