[udig-devel] Adding layers to existing map is slow

[milind suley <milind.suley@xxxxxxxxx>]

Hi All, 

Am facing some problem with display performance in uDig. Have had a brief one to one mail interaction regarding this with Jody and Jesse some time back and as suggested pursing this issue further on the forum. Am sharing some test results regarding a specific issue we observed.

We are dealing with big vector datasets with all types of features (points - symbols and text labels, lines, polygons) that use complex rule based styles that also refer to attributes to apply rotation, fonts etc.

What we observed is that once a map has some layers added to it, adding subsequent layers to it is very slow.

Our test case involves loading two similar datasets each having around 100 layers of all types of data containing around 20+ thousand features.

- Adding all layers of first dataset to the map took around 40 seconds (load + display)
- Adding all layers of second dataset to the same map took more than 5 minutes.

Then we tried another test:

- Add 90 layers (of the 100) from the first dataset to a new map - this took less than 40 seconds.
- Add remaining 10 layers from the same dataset to the same map - this took more than 1minute.

In both cases we observed that sufficient memory was available to the application and it had not reached memory limit. 

We believe a lot of redundant processing is happening when second set of layers is added to map. Perhaps this is due to notifications traffic within the application components (layer, map, renderer, layerview etc.). Has anybody else faced similar problem? Any suggestions on how to address the problem?

We  are using an older baseline of uDig code (1.2.0), but i believe internal application architecture is still the same. 

Any help in this regard would be appreciated.

Thanks,
Milind.