QGIS » QGIS Application

Here is my project.

Have you enabled multicore rendering?

Settings -> Options -> Rendering

I can't upload the project. The file is 12MB.

Yes, Multicore rendering is enabled. Rendering is very good once the project is loaded.

Per Gammerath wrote:

I can't upload the project. The file is 12MB.

dropbox (or similar)?

https://drive.google.com/file/d/0B8lAQWa28EprMVJSdDhVazNJLVE/edit?usp=sharing

I have been suspecting our project file of being messy and siltet, so I built a new project file and styled it to look like the original. The result was amazing, now the project loads in 16 seconds. This tells me, that there must be something wrong in the process of loading and saving project files. Our original project file was initially built in 2.0.1.
In the proces of building the new project file, QGIS crashed more than 20 times, just from organizing layers and loading styles. It's highly unstable.

Hmmm, just added all the composer layouts, and now everything is slow again. So maybe this is all about composer layouts.

In the proces of building the new project file, QGIS crashed more than 20 times, just from organizing layers and loading styles.

something that can be replicated every time?

Giovanni Manghi wrote:

In the proces of building the new project file, QGIS crashed more than 20 times, just from organizing layers and loading styles.

something that can be replicated every time?

It seems to be random. It crashed so many times that I had to save the project with each change to make sure I didn't have to start all over.

Giovanni Manghi wrote:

Per Gammerath wrote:

Hmmm, just added all the composer layouts, and now everything is slow again. So maybe this is all about composer layouts.

it is just enough to add one layout? does it need to contain a particular object to make slow the loading of the project?

I have 8 layouts, A4, A3, A2, A1, all with landscape and portrait orientation. I don't see how I can do without them.

If I'm right about the fact that Layouts slow down the loading of projects, would it be reasonable to let QGIS skip them and only load them when needed?

Per Gammerath wrote:

I have 8 layouts, A4, A3, A2, A1, all with landscape and portrait orientation. I don't see how I can do without them.

I didn't mean this.

As you said that you built the projects from scratch and that at some point you realized that it depends on layouts, then I would like to know if it was enough to add 1 layout (to get a slow to load project) and if the content of the layout made some difference.

For each layout I deleted, QGIS got faster. So I think it's about the number of layouts and not the content.
My layouts include a map, legend, small logo, date field and scale field.

One thing that would help track this down would be if you could try removing different item types from the compositions and testing whether a single item type is causing the slow down. For instance, if you remove all the scale bars from all the compositions does this make any difference to the project load speed?

Nyall Dawson wrote:

One thing that would help track this down would be if you could try removing different item types from the compositions and testing whether a single item type is causing the slow down. For instance, if you remove all the scale bars from all the compositions does this make any difference to the project load speed?

• Project file with 8 layouts including a map, legend, scalebar, logo
  30 seconds

• Project file with 8 layouts including a map, scalebar, logo
  24 seconds

• Project file with 8 layouts including a map
  23 seconds

• Project file with 2 layouts including a map, scalebar, legend, logo
  14 seconds

I think this indicates that the number of layouts and load speed is tied together.

Are they the only elements in your layouts? ( map, scalebar, legend, logos ?). No other items at all, like arrows or shapes?

Nyall Dawson wrote:

Are they the only elements in your layouts? ( map, scalebar, legend, logos ?). No other items at all, like arrows or shapes?

No other objects.

Giovanni Manghi wrote:

Paolo Cavallini wrote:

Better backport it to 2.4 branch?

#18a1c8a6360faf69a9b1bb9620b75baa7f1319cd#commitcomment-7044552

done in 904443ff0d49b3d6b6b883cb479ab2f0b5f5f6af

It opens and saves pretty much instantly for wihtout layout.qgs and a couple of seconds with layout.qgs project on my QGIS 2.8.2.

On my computer, there is a 11 seconds difference. To emphasize the problem, try and the duplicate layouts, and you will see that it takes even longer.

With 22 print layouts it loads in ~10 seconds for me now. With this no. of layout, I'd say it is acceptable!

You must have a really fast computer then. I'm running QGIS on a quad core 2.40 GHz, 4 GB ram. With 30 layouts, it takes about 30 seconds to load.
Nevertheless, I would like to know why QGIS has to process these layouts upon opening and not on demand?

Times for saving project on local C: or network H:

1. Projekt with composers (1-2 composers) on C: 1-2 sec
2. Projekt with composers (1-2 composers)on H: 24 sec
3. Projekt without composers on c: < 1 sec
4. Projekt without composers on h: 9 sec

Test times are from save until mouse react again. Test in 2.12

Per Gammerath wrote:

I see that this issue persists in QGIS Pisa. I still would like to know why the layouts can't be loaded on demand?

not sure about that, anyway I retested all the projects available in this ticket and loading time for projects with composers is somwhow slower than the projects without, but it is always in the few seconds range, really nothing that would led me to think about an issue to solve. I retested on master on both linux and windows.

I copied my project to a local drive and I realized that it didn't change the matter.

Project with 6 composers: 26 seconds
Project with 0 composers: 6 seconds

Please consider a solution for this annoyance.

OMG, can't believe I only found this bug now.

We deal with very large and complex (>150 layer) gis project files and they take forever to open. Now that I found this bug I was curious and did some benchmarks of our own:

• test file: 193 layers and 106 print composers
• test environment: QGIS 64bit on Windows 10, 8GB RAM, recent i3 dual core CPU (4 logical processors)
• measured from end of missing layer dialogue (artificially inserted to remove file loading times which is disk/network dependent) to the time the canvas is rendered
• with QGIS 2.8.8:
  • timing WITH print composers: 00:16:25 with 30-45% CPU usage
  • timing WITHOUT print composers: 00:00:03
• with QGIS 2.14.3:
  • timing WITH print composers: 01:09:56 with 30-45% CPU usage
  • timing WITHOUT print composers: 00:00:04

So QGIS 2.8 takes about 9 seconds and QGIS 2.14 40 seconds (!) for each print composer saved inside the .qgs file. I hope this helps to stress the severity of this bug, so please could the QGIS devs look into the code that loads and parses the print composers and remove the bottlenecks? If the info provided by the OP and others isn't sufficient, I could help in reproducing the issue.

Until then I guess we will all remove print composers from our projects and manage them outside QGIS...

Got the same problem as well under Linux, as under Windows 7 and 10. QGIS VErsion 16.3 and 16.1.
I got a project with about 15 Print composers, some of them quite large (about 60 x 90 cm). The QGIS-project has risen to a size of about 16MB, loading the project takes about 20 Minutes on a i5-3,4 GHz computer with 8 GB of RAM.
Also saving the project sometimes takes up to 5 minutes.
Makes working sometimes really annoying...
Guess this might be a major issue witch then could be more or less simply fixed by not loading all map layouts into the memory at start up.

With the changes merged in https://github.com/qgis/QGIS/pull/4279 all sample projects attached here load instantly.

My project files with many layouts still load painfully slow from network drives. I'm on version 2.18.14.