loading data through a view

[Fran çois Bruneau]

Hi everyone,

I am currently running some performance tests on MapServer, using an Oracle Spatial data set, and there are results that I have some trouble interpreting.

The debug mode outputs the precise fetch+render time of each layer. Here are the results I get: 

To load 50000 line objects through a "BENCH_LINE_50K" view defined as follows:
SELECT * FROM MY_LINES WHERE ROWNUM<=50000
it takes 178.937s.

To load the same objects but using a FILTER statement directly applied to the MY_LINES table, it takes only 2.938s ! 
 
Here is my layer definition:

  LAYER
	  NAME "BENCH_LINE_50K"
	  CONNECTION "safgis/safgis at lydec"
	  CONNECTIONTYPE oraclespatial
	  DATA "GEOMETRY FROM BENCH_LINE_50K"
	  #DATA "GEOMETRY FROM MY_LINES"
	  #FILTER "ROWNUM<=50000"
	  TYPE LINE
	  DEBUG ON
	  CLASS
	  NAME "BENCH_LINE_50K"
		  STYLE
			  COLOR 192 192 192
		  END
	  END
  END

Does anyone have an idea on what could explain this huge difference ?

Thanks in advance,

François.