Bug report #16368
QGIS Server (much) slower rendering than Desktop single thread after specific commit of release_2.14
|Affected QGIS version:||2.18.4||Regression?:||Yes|
|Operating System:||Debian Stretch||Easy fix?:||No|
|Pull Request or Patch supplied:||No||Resolution:|
|Crashes QGIS or corrupts data:||No|
On the same machine, with the same settings, the rendering time of QGIS Server Master/QGIS 2.18.4 and 2.14 latest is much slower then the d708473d5d9ab8e0ad55a7113d7bf9d94a087b2f commit of branch 2.14 which is quite good as a reference (with no known Server bugs).
I noticed this while testing for #15522 .
For my project (I can provide privately to a dev a smaller postgis dump + project where the performance issue can can be replicated) the time to render a specific region is:
- around 1.3 secs for all Qgis Desktop versions (single thread) for the region of my test GetMap request
- around 1.6 secs for QGIS Server the above specific commit (a little slower than the Desktop)
- around 2.95 secs for latest 2.14 build from source
- around 3.2 secs for latest 2.18 build from source
- around 2.85 secs for master single thread build from source
- around 2.7 secs for master double thread build from source
Each of the server version had an equivalent .qgs project version + no errors in the logs.
I have a hunch it's on account of my project using layer joins.