Improve library performance on large collections

This is really interesting and might contribute to the problem.

When selecting playlists, crates or other root models, BaseSqlModel::select() is called 3-4 times. This is inefficient for <LibraryFeature>TableModels that hold large data sets.

How to reproduce:
* Add a qDebug() to BaseSqlModel::select()
* Execute Mixxx and click on some playlists, crates, etc

This is probably because Mixxx does also call restoreSearch() on sidebar item changes which fires a select as well.

I traced back the issue to WTrackTableView::loadTrackModel(QAbstractItemModel *model)

Lines 105 and 108 call method setHorizontalHeader(). Transforming these lines into comments increase performance significantly. Only once select per sidebar item click instead of 4

Rryan: I probably break some functionality with that approach. Could you have a quick look or may be fix the bug? Any comments that directs me in the right directions are welcome.

Hey Tobias,

Yea, the select()'s are a problem. Uncommenting that select() debug is a good way to track the selects down. I did this a while back, but it's possible we regressed on how many select()'s we do.

Unfortunately Qt had a very nasty bug in WTrackTableViewHeader that made it so that columns would not update when you changed the QTableView's model. I don't know if it's fixed yet. If you comment out that setHorizontalHeader and everything still works (try switching modes to different views, try adding removing columns in one view and then switching back) then it might be fixed. We can remove it as long as it's fixed on recent Ubuntu versions and the version of Qt we use for Mac / Windows.

RJ

The question is which version we use for 1.9 for Windows and Mac? Still our customized 4.5.3?

Fix is in our features_library branch!
Only one line of code!!

I can use 4.7.1 for our next OS X packages. Not sure if that's viable
or not for Windows - Sean?

On Fri, Nov 12, 2010 at 12:53 PM, RAFFI TEA <email address hidden> wrote:
> Fix is in our features_library branch!
> Only one line of code!!
>
> ** Changed in: mixxx
>     Assignee: (unassigned) => RAFFI TEA (raffitea)
>
> ** Changed in: mixxx
>       Status: Confirmed => Fix Committed
>
> ** Changed in: mixxx
>    Milestone: None => 1.9.0
>
> --
> Improve library performance on large collections
> https://bugs.launchpad.net/bugs/672762
> You received this bug notification because you are a member of Mixxx
> Development Team, which is subscribed to Mixxx.
>

I can use latest Qt as well on Windows unless there are still graphics problems with it.

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/5643