Bug report #19203

QGIS 3.0 postgis rendering

Added by Angie Rudolph about 2 years ago. Updated about 2 years ago.

Status:Closed
Priority:High
Assignee:-
Category:Data Provider/PostGIS
Affected QGIS version:3.0.3 Regression?:No
Operating System:Windows 7 Easy fix?:No
Pull Request or Patch supplied:No Resolution:
Crashes QGIS or corrupts data:No Copied to github as #:27032

Description

This was previously reported but no solution was given. At this point I can't use 3.0 because the rendering from postgis is too slow.

"I have added data from PostGIS in Version 2.18 and the one data set loads in about 2 seconds. With the new 3.0 version, it takes 2 minutes to load that same data layer. All my data sets load really slow in Version 3.0. Not sure what the difference is from 2.18 to 3.0"

I also can't connect to the database using the DB manager, but that is a separate issue I believe.

postgresql2.18.log Magnifier (23.6 KB) Angie Rudolph, 2018-06-15 11:20 PM

postgresql3.0.log Magnifier (244 KB) Angie Rudolph, 2018-06-15 11:20 PM

Associated revisions

Revision ce74d57b
Added by Nyall Dawson about 2 years ago

[postgres] Really disable dynamic queue size

The original commit speed up some layers, but regressed
performance for others. It was decided to revert the
dynamic queue feature, but it seems this was never actually
done.

Fixes #16239, #19203

History

#1 Updated by Nyall Dawson about 2 years ago

  • Status changed from Open to Feedback

This has been reported a couple of times but no one has been able to provide the required debugging info.

Please check the postgis logs and report of there's any difference in the queries executed by 3.0 vs 2.18

#2 Updated by Angie Rudolph about 2 years ago

There is significant differences in the query logs.

Primary in 3.0 it is requesting each object individually

(see line 130 in attached postgresql3.0.log)

2018-06-15 14:52:59.847 MDT [17407] [email protected] LOG: statement: FETCH FORWARD 1 FROM qgis_1

In 2.18 it requests 2000 objects (see line 107 in attached postgresql2.18.log)

2018-06-15 15:04:03.519 MDT [17884] [email protected] LOG: statement: FETCH FORWARD 2000 FROM qgis_1

I have attached the two log files for your reference. Let me know if I should be logging something different.

#3 Updated by Nyall Dawson about 2 years ago

Thanks, that's perfect

#4 Updated by Nyall Dawson about 2 years ago

  • % Done changed from 0 to 100
  • Status changed from Feedback to Closed

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