Speed drop-off at around 99.90% of torrent completion (2.01)

[xenedar]

Using T 2.01 (Build 10898) and just experienced a behavior that I've observed in some earlier versions, certainly in 2.0:

I've been downloading a file, powering through it at speeds regularly more than 300 KB/s, as much as 600 at some points, easily sustaining well over 200. Around 99.90%, everything drops completely off, and it limps home at single-digit KB/s. I watched it go through about 10% of my 550-odd MB download in a minute or two, then spend a good 5 minutes struggling with the last 0.1%. This was a torrent where about 45 out of the 50 connected peers were seeders, and where one seeder was transferring at over 100 KB/s until the Big Slowdown. I know peer interest comes and goes, but it's like all of a sudden, everybody shunning me, as if they thought I had already reached 100%. (I don't suppose when T's talking to them, it's rounding up from 99.90 to 100%, so they think I'm done?)

I've seen this before, and I'm fairly certain it's always been around the same percentage. Unfortunately one of them was a multi-GB transfer, so rather than limping home in 5 minutes, it took the better part of a day, rarely more than 5KB/s and frequently virtually stalled, having previously transferred at reasonable rates of probably about 50-150 KB/s.

I'll pay more attention next time and see if I can get some more specifics, including what types/versions of peers are connected, and any logging. But has anyone else seen this?

[joaksmith]

Yes! Just started happening for me as well. (or at least i just started noticing it a couple of days ago)

Transfers stalls @ 99.99%. D/L goes to zero for between 1-5 minutes on a 1.36GB torrent before resuming D/L speed to finish.

I'm running T2.01 (10898) on mac OS X 10.5.8. Let me know if more information is needed for me to be helpful.

[AGSystem]

This has been round since before 2.0.
Quick fix is to pause torrent and then resume. this then usually re-downloads the affected piece (you will see it drop from 99.9% to say 99.87%).

Usually finishes the download in a few seconds after the last blocks are completed.

It was said to be due to some error checking 2.0 does now but i have seen 1.93 and 1.84 do it also, so may just be the trackers or at least related to them.

[gunzip]

yes it happens to me also starting with 1.92 and up in Linux. there's about a half-dozen threads about this odd behavior here in the forums over the last few months, e.g.,

"Always slows down when nearly done": viewtopic.php?p=45964

i noticed the slowdown is very small with private trackers, but on public trackers with large swarms TR can sputter for several minutes at the very end eventhough a ton of seeds are available. maybe it's anti-p2p activity poisoning the torrent pieces and TR has a hard time finishing it off. as mentioned, pausing/resuming the torrent is a quick fix but then you have to babysit the torrent at the endgame.

i don't think this has been acknowledged as a bug yet, but nevertheless it is a bit alarming.