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Comment by subie | Hacker News Reader

I had heard Spotify uses P2P quite a bit.

People on this forum are reporting that its eating up 50GB's on idle. Could it be possible they are using idle clients to help stream content to other users?

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They have stopped using P2P for some time now.

https://techcrunch.com/2014/04/17/spotify-removes-peer-to-pe...

Based on quick glance to the thread, somebody has pin pointed the problem to embedded SQLite database vacuum operation. That is optimizing the storage of database and maybe it is being called too often.

isn't the vacuum operation's job to reduce database size by removing free space and defragment the data?

edit: ok, I got the answer by myself: apparently, Vacuum copies the database to a temporary file and then it overwrite the original, it's not the usage, it's the writes that are the problem here.

Spotify has a few nifty features that must be using a fair bit of bandwidth. Features such as the ability to remote control another instance means maintaining a control channel. The ability to switch music to your local device means all devices must stream the song, as though it were playing on that device, to allow immediate switching.

These work quite well for the user, as it's enjoyable to listen to music on your stereo at home, then just tell the phone app to switch from your stereo to your phone (maybe over headphones) while you're mobile. And heavy use of P2P between devices on the same LAN or Wifi network would reduce internet bandwidth use, but may unintentionally cause a lot of churn and disk use.

Spotify doesn't forward the stream. When you tell it to play with another device that's running Spotify, it simply instructs that device to play the stream; unlike AirPlay it doesn't send the music to that device.

I can attest to this.

Playing a song from a phone 'pushing' to a device on a slow connection always causes troubles for me.

Okay but streaming content is a read operation, not write.

Not if they have your computer get content to serve, perhaps based on popularity.

They could be "pushing" the most popular content to those clients for the others benefit even if you never listen to it.

Spotify used to be P2P, several years ago. These days it streams directly from Spotify's cloud servers (or technically Google's).

It looks like most of it is being written to a SQLite DB, so probably not.

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