uTorrentPartFile keeps growing unnecessarily

[ady4um]

I already posted a thread related to uTorrentPartFile growing and growing, and it is still growing. Since I couldn't find a solution then, I must report this behaviour (as a bug IMO).

If anyone would like to check it, my troubleshooting post about this issue is

http://forum.utorrent.com/viewtopic.php?id=41294

ut 1.8 beta 11086

bt.compact_allocation=false

diskio.sparse_files=false

unchecked pre-allocate all files

pieces are 4 MB each (16 kB * 256 blocks)

When sorting the files by "First piece" column, the torrent consists of:

A) 1 group of subsequent continuous unskipped, completely downloaded files

1 group of subsequent continuous skipped, not downloaded files

C) 1 group of subsequent continuous unskipped, completely downloaded files (till the torrent's end)

When the multifile torrent was added, I skipped all files (right from the start, in the add dialog).

Then I unskipped some subsequent continuous files.

UTorrentPartFile keeps growing, even when all the unskipped files are subsequent except for the (also) subsequent group named B above.

I already tried the following steps:

1- All unskipped files were downloaded completely (no unskipped file was partially downloaded).

2- Just 2 skipped files (from group B above) have blocks in already-downloaded pieces (skipped and unskipped files that have pieces in common).

3- I quit ut, moved the uTorrentPartFile to an unrelated folder, started ut again, forced re-check. Since everything was ok except the pieces that skipped files and unskipped files have in common (as expected), I unskipped 1 subsequent file (the first file of group B, as described above).

4- When all the unskipped files were downloaded completely, I stopped the torrent and quit ut.

For my surprise, after all these operations, the new uTorrentPartFile was growing again bigger than 8 MB.

Since the pieces are 4 MB each, and since at any given time I have just 2 pieces that contain both skipped and unskipped blocks, the uTorrentPartFile was supposed to be not-bigger-than 8 MB.

Each time I unskipped a file which has blocks already downloaded (in uTorrentPartFile), ut should be using the blocks from uTorrentPartFile, not downloading them (again). Accordingly to the "files" tab, this *is* happening. But then, if those blocks *are* being used afterwards in the recently unskipped and completely downloaded file, then they should be removed from the uTorrentPartFile once the blocks are saved, at least when the unskipped file is completely downloaded. Those blocks are not part of skipped files anymore.

UT IS NOT REMOVING THE UNNECESSARY BLOCKS FROM UTORRENTPARTFILE.

The file keeps growing unnecessary.

Maybe the devs could confirm this?

Is this "growing-and-growing" behaviour expected?

I know ut cares about pieces, not files. But still, ut knows which blocks it should save in the uTorrentPartFile and which ones are being saved as unskipped, completely downloaded files, so obviously ut also knows which blocks are part of an entire unskipped file and which ones are part of a skipped one. Using the same reasoning, when a skipped file turns into an unskipped one, the corresponding blocks which were saved in uTorrentPartFile are, from that same moment, part of the file being downloaded (or queued download). In this reasoning, when this recently unskipped file is completely downloaded, there is no need to keep those blocks in the uTorrentPartFile.

If a file previously skipped is now unskipped and completely downloaded, why the previous blocks are still in uTorrentPartFile? As I said, they shouldn't, since they are not part of skipped files anymore.

Is there any reason to keep those blocks twice (once in the complete files and once in uTorrentPartFile)?

Thank you in advance.

[Firon]

Removing the blocks would require completely recreating the partfile.

[ady4um]

Firon, thank you for your answer.

First, I would like to know if there is any way for me to somehow "cut" the unnecessary data in the uTorrentPartFile.

Coudn't ut "recreate" the uTorrentPartFile, discarding the unnecessary data, and using the really useful one, without redownloading it again?

Maybe, this should be a manual (not automatic) advance function? Or maybe, this could be optionally included in the "force re-check" function?

Please understand the following situation (I will be writing in "first person", but this could be anyone's issue).

I want to download the whole torrent, which has more than 200 files and a total of 25.8 GB. Since the size of the whole torrent is too big for me to download it as a whole (specially because I'm being throttle to less than 4 kB/s dl speed, most of the time even much worse than that), I decided to unskip 1 file at a time, subsequently. I am not deleting the files I download, and they are available to seed. The point of unskipping 1 file at a time (while letting the already downloaded files also unskipped) is to get the file completely, instead of having hundreds of distributed pieces, from 25.8 GB, being downloaded for months without having the possibility to complete a file and using the disk space for other things.

So I am completing the whole torrent gradually. In the past I have already deleted the uTorrentPartFile, since its size was already 80 MB, while actually just less than 8 MB where useful, and the rest was already saved as completed unskipped files. Of course, after deleting those 80 MB I had to download the useful 8 MB again, but I was hoping the problem would be solved in the beta builds. Yes, I call it a "problem", and here's why.

First, as I said before, most of the data in the uTorrentPartFile is already saved as completely downloaded files, so there is wasted disk space (I am getting again a "big" utorrentPartFile). This is independent of why or how I got those pieces. The point is, they are not needed in the uTorrentPartFile any more.

Second, let say I finally get to download all the pieces and all the files are unskipped. Then I should be seen as a seeder with 100% of the torrent. But this is not the *only* thing related to this torrent that I would have in my disk, because I also will have hundreds of MB inside the uTorrentPartFile, which actually I wouldn't need anymore! And keep in mind that I added the torrent with *all* the files skipped (right, in the add torrent dialog, before actually adding the torrent). So this situation is not as bad as if I add the torrent and *then* I select to skip files. In this case, the uTorrentPartFile would be even bigger.

OK, I know, if I finish downloading *all* the files, then I *could* remove the torrent from ut and add it again, which will delete the uTorrentPartFile and let me seed the whole torrent. Until I get all the files, I can't do this, because ut will delete also the 8 useful MB of uTorrentPartFile. This is not an option when I am downloading so slow.

Don't you think this is a waste of resources? And what about users not knowing about this? They could be letting uTorrentPartFiles over the disk, even when they don't need them.

Moreover, in this scenario, if by any chance the most recent unskipped files are just finishing the piece, so there is no "shared" pieces between skipped and unskipped files? I mean, first X pieces downloaded and they just complete the first group of files. In this case, I shouldn't need any uTorrentPartFile, at least when this first group of files are completely downloaded.

Firon, I would really appreciate if you and the others mods and devs could take a moment to read this thread and to consider a possible improvement to the uTorrentPartFile management, or a workaround to this situation. This issue could be meaningless to people with fast downloads and "infinite" available disk space, but it is important to people without such resources.

I would also appreciate if you could post and update about this issue. Thank you in advance.