Postgis View Layers with OID as primary key are loading very slow

[qgib]

Author Name: Horst Düster (@hdus)
Original Redmine Issue: 1855

Redmine category:data_provider
Assignee: Jürgen Fischer

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I want to load a postgis view layer defined in a way that the OID represents the primary key of the view query result. No real primary key is defined in the source tables. When I query this view from psql it gives me the query result very fast. When I load this layer into QGIS it needs a very long time, more than 1 minute, to load this layer.

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• 1855_selectpkey.diff (Jürgen Fischer)

[qgib]

Author Name: Giovanni Manghi (@gioman)

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Hi,

what version of qgis are you using? platform?

[qgib]

Author Name: Horst Düster (@hdus)

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svn cbf7cf6 (SVN r11253)
kubuntu 9.04
postgres 8.4.0

[qgib]

Author Name: Jürgen Fischer (@jef-n)

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Replying to "hdus":/issues/show/1855:

I want to load a postgis view layer defined in a way that the OID represents the primary key of the view query result. No real primary key is defined in the source tables. When I query this view from psql it gives me the query result very fast. When I load this layer into QGIS it needs a very long time, more than 1 minute, to load this layer.

Does "loading" mean only "inserting" or "displaying"? Inserting the view to the project can be slow, while QGIS tries to figure out what the primary key column is. Once that's done displaying should be quick. Saving the project and reloading it should be also quick as QGIS saves the key column it found.

If you add the layer using python you can also specify the key column using key=column and QGIS will just verify that it's unique.

See also #11595

[qgib]

Author Name: Horst Düster (@hdus)

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Replying to [comment:3 jef]:

Replying to "hdus":/issues/show/1855:

I want to load a postgis view layer defined in a way that the OID represents the primary key of the view query result. No real primary key is defined in the source tables. When I query this view from psql it gives me the query result very fast. When I load this layer into QGIS it needs a very long time, more than 1 minute, to load this layer.

Does "loading" mean only "inserting" or "displaying"? Inserting the view to the project can be slow, while QGIS tries to figure out what the primary key column is. Once that's done displaying should be quick. Saving the project and reloading it should be also quick as QGIS saves the key column it found.

If you add the layer using python you can also specify the key column using key=column and QGIS will just verify that it's unique.

See also #11595

Loading means inserting. I took a look at the comments of #11595 and there gjm talked about an option to select the primary key column by the user when he is loading the postgis layer. Maybe it is possible to make some changes of the Postgis loader UI in this direction?

[qgib]

Author Name: Horst Düster (@hdus)

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Replying to [comment:5 jef]:

Thank you for the patch. Yes in this way it works fine for me!

[qgib]

Author Name: Jürgen Fischer (@jef-n)

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applied in d6134d5 (SVN r11480)

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• resolution was changed from to fixed
• status_id was changed from Open to Closed