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Tendency to download the last pieces
Posted: Sun Mar 13, 2016 6:28 pm
by Zi
I always notice that it tends to download the last pieces even with highly available and seeded files.
The attached image is 700 MB file at 25%. BTY, even those green/partial pieces at the start they are there since it was 10%.
It annoys when I suddenly need to download in sequential order to watch a movie for example.
What do you think?
Re: Tendency to download the last pieces
Posted: Mon Mar 14, 2016 12:49 am
by Zi
Update at 80%. Should it be random rather than filling the end of files at first?
Re: Tendency to download the last pieces
Posted: Tue Mar 15, 2016 10:18 am
by KitKat
[quote="Zi"]
It annoys when I suddenly need to download in sequential order to watch a movie for example.
What do you think?
[/quote]
Actually in (most) cases with movie playback (streaming) you need the metadata from the end of the file for the video player to actually play the file so SOME downloaded data at the end is actually preferable.
Also the 3.4.0 alpha branch incorproates an "optimize for streaming" option which should make this case alot less frustrating
What version of qbittorent are you using?
Operating System?
Did you change any download settings eg specify high priority/skip for some files?
Because that could affect the download sequence if its a multifile torrent.
Re: Tendency to download the last pieces
Posted: Tue Mar 15, 2016 1:17 pm
by ciaobaby
I always notice that it tends to download the last pieces even with highly available and seeded files.
They are probably the 'rarest pieces' in the swarm, and
demonstrates perfectly why 'sequential' piece downloading is bad for swarm 'health' and you are getting the 'fallout' from other peers using sequential downloading.
Should it be random rather than filling the end of files at first?
No.
Re: Tendency to download the last pieces
Posted: Thu Mar 17, 2016 12:15 am
by Zi
[quote="KitKat"]
What version of qbittorent are you using?
Operating System?
Did you change any download settings eg specify high priority/skip for some files?
[/quote]
qb v3.3.3 on Windows 10. No settings or priority changed.
[quote="ciaobaby"]
They are probably the 'rarest pieces' in the swarm, and
demonstrates perfectly why 'sequential' piece downloading is bad for swarm 'health' and you are getting the 'fallout' from other peers using sequential downloading.
[/quote]
I thought the first pieces are the one should be highly available, if the torrent suffers from sequential downloading. The example I provided has several thousands seeds, probably most seeded movie that weekend
Thanks
Re: Tendency to download the last pieces
Posted: Thu Mar 17, 2016 11:30 am
by KitKat
[quote="Zi"]
I thought the first pieces are the one should be highly available, if the torrent suffers from sequential downloading. The example I provided has several thousands seeds, probably most seeded movie that weekend

Thanks
[/quote]
IIRC Bittorent protocol asks for the
least common pieces first in an attempt to create a scenario where if all the seeders mysteriously vanish its more likely that the remaining peers can complete the torrent download and create new seeders, thus preventing a "dead torrent" scenario with 100 peers stuck at 90%.
/e: Theres some autistic java based webkit program that streams torrent movies that is becoming more popular lately.
Afaik its a dedicated leecher thing aswell/doesnt seed at all so if the torrent you're downloading IS extremely popular then its very likely the end parts of the file are vastly less common among the peers.
Re: Tendency to download the last pieces
Posted: Thu Mar 17, 2016 12:34 pm
by ciaobaby
I thought the first pieces are the one should be highly available,.
Exactly; however as the default downloading strategy for ALL
well behaved bittorrent protocol clients is to request the
rarest pieces first which
will of course be the pieces at the end of the payload the whole swarm suffers because of several inconsiderate and selfish users.
Re: Tendency to download the last pieces
Posted: Mon Mar 21, 2016 12:22 pm
by Zi
Got it. Thank you very much.