I have polygon table called "tableA" with 72000 records. It has a geometry column called "geometry", and a text column called "field1". I want to aggregate\dissolve all polygons with the same "field1" value.
I have a Spatial Index in Geometry and an index in field1.
I tried this:
Select f.field1 as field1, st_union(f.geometry) as geometry From tableA as f Group by field1;
and its taking too long, I had to cancel it after being processing for 1 hour. Using Arcgis it toke me 5 minutes, so I must be doing something wrong.
So, is there a better way to preform this operation using spatialite? Is the Spatial Index being used this way?