[fdo-users] Another FDO PostGIS Selection Problem

Mateusz Loskot mateusz at loskot.net
Mon Mar 17 14:45:51 EDT 2008

ary sucaya wrote:
> Hii all,
> I have another selection problem on PostGIS FDO with MapGuide OS. I
> attach a small bitmap to describe my problem. Referring to that
> attachement, i have 2 rectangle of 500 m x 500 m. If I do a click
> outside the rectangle (red dot), MapGuide OS response is very very
> slow. It takes around 5 minute until refreshed. If accidently I do
> another click, my browser will hang. From my observation, it look
> like a heavy process took place. Mgserver use 98,781 K of memory
> during that process and decrease into 65,444 K when the process
> finnish. The area inside rectangle (green dot) is fine, the response
> quick enough. Is there a way to speed up deselect process? I make use
> of FDO 3.3 and MapGuide OS 2.0

Have you checked if similar problem occurs with ie. MySQL provider?
It's important to identify on which side is the problem: the provider,
FDO framework or MapGuide.

I'd suggest to enable SQL statements logging for PostgreSQL, walk again 
through all problematic interactions and check what SQL statements are 
executed. Next, I'd execute every statement manually, in psql or pgAdmin
and observe performance.

This should give rough answer if the problem is PostGIS provider fault 
or not.

Also, don't forget to:
- generated GiST index

see 4.5.1. section in the PostGIS manual

Mateusz Loskot

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