Bug 321299

Thanks for the report. Some questions:

(a) Do you use "Sort by Name/Size/Type", or something else?

(b) Do you really see a difference between KDE 4.10 and 4.11 beta 1 in small folders (500 items or less)?

There are some changes regarding the loading of data which are very expensive to retrieve (like icons, mime types, folder contents count, etc.): https://git.reviewboard.kde.org/r/110839/

However, even in KDE 4.10, the folder size and mime types were in general not loaded immediately. I just tried it again, and I can definitely see that the columns are filled asynchronously after the initial loading. How fast that happens depends on many different factors though. If it happens fast enough (like when everything is cached by the kernel already), it could appear that it happens instantaneously.

The main difference between the old and the new implementation is that we do not retrieve the data for all items any more if there are more than 500 items in the folder. The reason is that mime type determination and things like that can easily keep the CPU and the hard drive busy for several minutes (but without blocking the GUI) when entering a folder with many items. There were user complaints at the forum and other places about this, and that's why I changed it.

We now only load the data for the items in the visible area, those a few pages before and after, and those on the first and last page of the view, i.e., those which can be reached quickly.

But as I said, with less than 500 items, the behaviour should actually not have changed much (even though there are a few glitches in some corner cases, which will be adressed before beta 2).

a) Detail columns sort by name
b) I don't recall this behaver in 4.10 and we are talking folders with 7 folders and 14 files and even smaller (only 5 files and I'm seeing type being filled)

The strange thing here is if I "kdesu -u" to open my test user's Dolphin this behavior is not being seen.  Renaming ~/.kde4/share/config/dolphinrc doesn't fix it but the behavior  is sort of erratic sometimes it does and then it doesn't

Toggling natural sorting doesn't fix it either

Thanks for the quick reply. I'm afraid I can't say what the problem is then (or if there is a new problem compared to KDE 4.10 at all).

Instructions to reproduce the problem would be appreciated. As I said, there will be some more changes until beta 2, so it would be great if you could re-test it then.

To reproduce - just open Dolphin.

Logging in as my test user and no problem with the same folders - there is something in my config causing it but no idea what it could be. And pretty darn sure I did not experience this in 4.10.x

Running  kbuildsycoca4 --noincremental  did not help, will later erase kdecache

Obviously will test when beta2 is available

thanks,

> To reproduce - just open Dolphin.

OK, your comment 2 sounded like the behaviour is erratic/non-reproducible. But anyway, I could not observe a difference to KDE 4.10 yet.

my first screen capture and my first youtube upload

http://www.youtube.com/watch?v=z4wsDav-15Q&feature=youtu.be

played around with Dolphin config and apps file/folders and found that deleting "~/.kde/share/apps/Doplhin/view properties" seems to have solved the problem - does this make any sense?

Created attachment 80622 [details]
my view properties foilder that appears to have caused the problem

Thanks for the update - good to know that it works now!

(In reply to comment #7)
> played around with Dolphin config and apps file/folders and found that
> deleting "~/.kde/share/apps/Doplhin/view properties" seems to have solved
> the problem - does this make any sense?

That obviously depends on how you customized the view after you removed the view properties folder ;-)

I see that you had an "Image Size" column in your video. If removing that one fixes the problem, then it might have something to do with our interactions with Nepomuk. I don't think that anything important has changed on the Dolphin side, however.

Nepomuk was not enabled, though at one time it was and when it was "image size" was checked

Enabling Nepomuk (and not file indexing) and having image size checked then disabling Nepomuk and the issue returns

I think there's an issue with the interaction with Nepomuk, especially strange how it was disabled at the time

Thanks for the new information. I'm not really familiar with the Nepomuk internals, but if you enable a column that can only be filled with Nepomuk's help, and indexing is disabled (such that no fast retrieval of the information from the database is possible), then it's probably not surprising that there is a delay.

I would then think that this would be a bug, the attempted retrieval of data no longer available because a process (Nepomuk) is no longer enabled. 

If Nepomuk is not available then those columns provided by it should not be attempted to be filled. Is this done by Dolphin or by a KDE lib?.

As this wasn't an issue with 4.10 then I would think it should be considered a regression.

I had similar problems after upgrading to KDE 4.11 Beta 1.

I have a folder with 23 folder and 81 files + Show in Groups + Show Preview + Additional Infomation: Size, Data, Rating + Sort by Type

It took > 45 seconds to open this folder (UI was frozen) and a lot of nepomuk and soprano errors appeared. 

Solution for this problem:
I have completely removed the nepomuk database and re-indexed my home directory -> Everything works fine and really fast now.

Thanks for the update. But then it sounds like it's due to changes in Nepomuk, and we can't do much about the issue in Dolphin. Even though quite a few things have been changed in KFileItemModelRolesUpdater, the way we talk to Nepomuk should be unaffected by these.

I'll reassign to Nepomuk. @Vishesh: Feel free to close this if re-indexing the home directory is the recommended way to make everything work smoothly in KDE 4.11 (but then this should maybe be announced somehow).

This doesn't seem like a Nepomuk problem. It seems more like an issue of Dolphin trying to use Nepmuk when it isn't running, and because of that there is a delay. The main reason this delay is more obvious is that with 4.11 connecting to Nepomuk is a lot more expensive. In 4.10 days we just connected to a local socket. With 4.11, a full connection is made to virtuoso.

Therefore, dolphin should not unnecessarily try to use any of the Nepomuk2::Resource classes when it knows Nepomuk is not running. This is because each use of them attempts a connection to Nepomuk.

Created attachment 80673 [details]
A Patch which fixes the issue on the Dolphin side

This almost fixes the issue, there is still a problem of the Nepomuk2::FileMetadataWidget attempting to connect to Nepomuk multiple times. I'll fix that in the nepomuk-widgets repository.

A slight problem with this patch is that the roles are not updated if Nepomuk is switched off, Dolphin is started and then Nepomuk is started. This problem was always there, but a refresh used to fix it. Now one needs to restart Dolphin.

Thanks for looking into the problem so quickly, Vishesh!

(In reply to comment #16)
> Created attachment 80673 [details]
> A Patch which fixes the issue on the Dolphin side

This looks good from my point of view, feel free to commit that to master!

Git commit 44791e7f155024d0c8961f907544676eebd5ea17 by Vishesh Handa.
Committed on 20/06/2013 at 18:39.
Pushed by vhanda into branch 'master'.

Dolphin: Do not try to connect to Nepomuk if it is not running

Each time one uses any of the Nepomuk classes, an attempt is made to
connect to the database. This slows down the application since
connecting to Nepomuk is not so cheap.

M  +29   -22   dolphin/src/kitemviews/kfileitemmodelrolesupdater.cpp

http://commits.kde.org/kde-baseapps/44791e7f155024d0c8961f907544676eebd5ea17