I just ran a test
Ubuntu Linux
QGIS 2.16.2
Shapefile with 925,000+ polygons
I opened the attribute table which took a bit.
Started editing.
Split 5 polygons.
Saved.
Stopped editing.
Removed the layer.
Added it back - it didn't corrupt.
I'm wondering if I should have done something more deliberate like
delete or add more polygons.
Randy
On 09/16/2016 06:00 PM, Jeff McKenna wrote:
On 2016-09-16 3:53 PM, Even Rouault wrote:
One of my hypothesis is some bad interaction with the "connection pool".
Could you (or anyone) open the attribute table before doing the
edits,and do
the edits and commit them no more than 60 seconds afterwards ? I'm
not sure
but this might perhaps also require the shapefile to be big enough
(several
thousands of features).
Here was my next test:
- download OSM land polygons for the world, unsplit:
http://data.openstreetmapdata.com/land-polygons-complete-4326.zip
424MB 568,635 features <--- big test!
- add shapefile to QGIS 2.16.2 view
- open attribute table
- start editing
- after a while waiting for nodes to appear as QGIS works, message is
displayed of "qgis-bin.exe has stopped working"
With QGIS 2.14.0:
- exact same issue when starting editing of that layer
With QGIS 1.8.0:
- able to click start editing and no crash as nodes are displayed for
world
- able to use "Split Features" and save edits
- seems to write changes to .dbf .shp .shx (to be honest, changes
don't look like a valid feature split, hard to tell, but it seems a
few more feature records were added)
You likely aren't happy that I tried with such large of a file, but,
it was honestly the first big file that I found.
====
other test for fun:
- checked layer summary through ogrinfo
- indexed the .shp with the shptree utility (generates 22MB .qix index
file, wow)
- created a small MapServer mapfile with only that layer, for world
extents
- generated map image through MapServer, recording layer draw speed
(cool!)
- tried to compare that speed, to QGIS 2.16.2 loading that same
shapefile (doing both a same time)
Fun results! Any guess how MapServer did? :)
Honestly I didn't plan to check that, and that is not why I tried to
help here, but when I saw QGIS having a hard time with this large
file, on a 16MB RAM new machine, I thought 'hmm i wonder how MapServer
would handle this huge file?' For one of the previous WMS
Benchmarking exercises at an old FOSS4G event I tested with a 1GB
shapefile, and we had to fix the indexing for MapServer...so it is
good to try to push limits once in a while.
sorry if i offend anyone with these tests, was just having some fun
pushing MapServer as well.
Let me know if you need more tests.
-jeff
--
------------------------------------------------
Randal Hale
North River Geographic Systems, Inc
http://www.northrivergeographic.com
423.653.3611 rjh...@northrivergeographic.com
twitter:rjhale http://about.me/rjhale
http://www.northrivergeographic.com/introduction-to-quantum-gis
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