QgsVectorDataProvider.createAttributeIndex() fails in QGis 1.8

Question

Adding an Attribute Index to a Shapefile fails for a Python Plugin in QGIS: For example - the following python Code in a Plugin

ly = QgsVectorLayer(data_source, layer_name,"ogr")
prov = ly.dataProvider()
prov.createAttributeIndex(i)

results in the error Message:

'QgsVectorDataProvider' object has no attribute 'createAttributeIndex'

Whereas Adding a Spatial Index works without any problem

ly = QgsVectorLayer(data_source, layer_name,"ogr")
prov = ly.dataProvider()
prov.createSpatialIndex()

Is this a Bug?

Thanks in Advance

Answer 1

This method is not exposed to python in QGis 1.8, but it is in the current development (master) release.

Please be aware, that before calling createAttributeIndex(), you should check the provider capabilities:

if prov.capabilities() & QgsVectorDataProvider.CreateAttributeIndex:

but for the ogr provider this is implemented and if you are sure you are always dealing with this data provider this step can safely be skipped.

If you notice no performance impact after creating an index, that is most likely a problem in the provider, as QGis itself does no indexing and only forwards the create index request to the data provider.