[Qgis-user] Qgis crashes while loading WMTS layers
Patrick Dunford
enzedrailmaps at gmail.com
Thu Mar 12 23:24:37 PDT 2020
In the last few weeks I have been doing a lot of testing with various
test environments.
At the moment I can't replicate the problem.There seem to be no issues
with 3.4.15, 3.10 or 3.12
On 2/02/20 5:25 am, Jonathan Moules wrote:
> Hi Patrick,
>
> I'd suggest reporting this to the QGIS bug tracker as a regression.
>
> Cheers,
>
> Jonathan
>
> On 2020-02-01 07:20, Patrick Dunford wrote:
>> Further investigation and comment
>>
>> Since recently installing Qgis 3.4.15 or 3.4.14 on some of my
>> computers running Debian 10, I immediately began to see a trend of
>> the software exhibiting an increased tendency to crash when working
>> with certain WMTS layers that I had previously worked with
>> extensively over recent weeks for mapping purposes.
>>
>> After attempting numerous changes including special versions of
>> projects containing no file based raster layers and only containing
>> one WMTS layer at a time and being unable to use the software
>> regardless I created a virtual machine running Debian 9 which has the
>> latest version available for that platform, 3.4.4. This has resulted
>> in immediate major improvement in the reliability of the software to
>> the point I can resume using it without the numerous crashes of the
>> software that have been noted recently, especially in the last week
>> approximately.
>>
>> On 27/01/20 1:19 am, Patrick Dunford wrote:
>>> Good day to all.
>>>
>>> Not so long ago I wrote a post about issues handling large numbers
>>> of raster files. This results from what appears to be an
>>> architectural design limitation of Qgis in that it only has enough
>>> resources available for a certain (unknown) number of raster layers
>>> and does not have any effective system for dealing with the
>>> exhaustion of these resources.
>>>
>>> I also noted that the software does not appear to have the ability
>>> to use the swap (virtual memory) resources within a system to deal
>>> with the apparent exhaustion of resources, as other software would.
>>> For example, Gimp which I use for graphical editing is able to
>>> handle certain projects using a swap space of 200 GB, which consists
>>> of 32 GB of physical RAM and the rest in SSD. It is not unusual with
>>> some of these graphics projects to have 100 GB or more of swap space
>>> in use, without crashing the system. (This being possible since Gimp
>>> 2.10 with its ability to write files of more than 4 GB)
>>>
>>> Whilst it is possible to manage the number of layers with file based
>>> rasters, this cannot be done with a WMTS server because there is no
>>> way I am aware of to manage the number of layers that can be
>>> downloaded from the server.
>>>
>>> Version 2.18 and earlier almost never crashed with excess layers,
>>> usually all that would happen is a layer would be displayed with
>>> invalid data. However, crashes have become the norm with 3.x
>>> versions of software.
>>>
>>> It seems to me there is a big architectural problem in the software
>>> with its inability to utilise the full resources of the system in
>>> order to process the number of layers that a WMTS server is capable
>>> of issuing.
>>>
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