$rectObj->project() function very slow in MS 6

[armin]

For layer query results I need to extract the bounding box of the features found with the query. I use the function

$bounds = $shpObj->bounds;

If map and layer projection are different it is necessary to reproject the bounds rectangle returned for the shapes of a layer to the projection of the map. This is applied with

$bounds->project($inProjObj, $outProjObj);

This works fine with MapServer 5.6, the projection does not cause the query to take noticeably more time than without projection. In MapServer 6 however the project() call causes a huge overhead. Just as a comparison:

a result for a point layer returned via $layer->queryByRect(), number of results = 996 records, takes the following time when applying the project() on every shape of the query result:

• MapServer 5.6.7: 0.015 seconds
• MapServer 6.0.2: 3.5 seconds

So MS 6 takes more than 200 times longer. If the project() call is disabled MS 6 is as fast as MS 5.6.

I attached the script that I use for the testing. The time measuring needs PEAR Benchmark package installed. I will add also a zip with map file and test shapefile.

Used environment is: Ubuntu 10.04-64, MapServer compiled from source.

[armin]

I made the test now on three different machines, two with Ubuntu 10.04 and PHP 5.3, one with Debian 6 and PHP 5.2. The same effect for all of them. When applying the project() call to the shape bounds, the script is ~200 times slower with MS 6 than with MS 5.6

[armin]

I did a few more testing. The problem seems to be related to reprojection of point bounds where minx=maxx and miny=maxy. If I replace the line

  $bounds->project($inProjObj, $outProjObj); 

with

  $oRect = ms_newRectObj();
  $oRect->setExtent($bounds->minx, $bounds->miny, $bounds->minx + 0.01, $bounds->miny + 0.01); 
  $oRect->project($inProjObj, $outProjObj);

then the speed is the same for MS 6 and 5.6.

[aboudreault]

Thanks armin for this interesting ticket. It is certainly something I need to check before 6.2.