QGIS fails to copy all selected features to clipboard for large OSM datasets

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Author Name: Mathieu Pellerin - nIRV (Mathieu Pellerin - nIRV)
Original Redmine Issue: 20308
Affected QGIS version: 3.4.0
Redmine category:vectors
Assignee: Even Rouault

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(I'm not in a position to confirm that this is a regression from previous versions, but it could well be)

On QGIS 3.4, copying to clipboard a large number of selected features in a large OSM dataset layer fails. Instead of copying all features, only a few features are actually inserted into the clipboard (for e.g., out of 2,500 selected features, between 1-10 features are copied). If you try to copy selected features twice in a row, the second time will lead to QGIS freezing.

Steps to reproduce:

• Create a new project, and add the following OSM dataset (use the points layer): http://imhere-asia.com/pp.zip
• Select a large number of points
• Hit the copy button on QGIS' main toolbar
• Paste the copied features (either as new scratch layer, or in MS Excel/LO Calc), notice it'll be missing most features
• Hit the copy button on QGIS' main toolbar again, notice how QGIS freezes (you'll need to kill it)

[qgib]

Author Name: Even Rouault (@rouault)

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#8397

[qgib]

Author Name: Even Rouault (@rouault)

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Applied in changeset 986e11b.

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• done_ratio was changed from 0 to 100
• status_id was changed from Open to Closed

[qgib]

Author Name: Even Rouault (@rouault)

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• regression was changed from 0 to 1

[qgib]

Author Name: Giovanni Manghi (@gioman)

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I have noticed that opening the table of attributes it only shows 99 rows, is this a consequence of this bug?

[qgib]

Author Name: Even Rouault (@rouault)

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Giovanni Manghi wrote:

I have noticed that opening the table of attributes it only shows 99 rows, is this a consequence of this bug?

No, this is a different issue. A quick investigation shows that it is due to
{{{

void QgsVectorLayerCache::setFullCache( bool fullCache )
{
mFullCache = fullCache;

if ( mFullCache )
{
// Add a little more than necessary...
setCacheSize( mLayer->featureCount() + 100 );
}}}

In the case of a OSM layer,mLayer->featureCount() returns -1 to indicate that the feature count is unknown, hence -1+100 = 99. I'm not familiar enough with this piece of code to fix that quickly

[qgib]

Author Name: Giovanni Manghi (@gioman)

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Even Rouault wrote:

Giovanni Manghi wrote:

I have noticed that opening the table of attributes it only shows 99 rows, is this a consequence of this bug?

No, this is a different issue.

thanks for the explanation, I filed a different ticket.