Hi, I published a Postgis-raster table as a Mapserver WCS layer using gdal-1.10dev driver. I'm getting the expected result as output of my Getcoverage query but I'm concerned by the time required to extract the data. It takes about 3 minutes to extract a 4800 x 4800 pixels area. I looked at the SQL queries performed against the database during data processing and found that an extent query is always performed in order to get the current extent of my layer using the following SQL query:
select srid, nbband, st_xmin(geom) as xmin, st_xmax(geom) as xmax, st_ymin(geom) as ymin, st_ymax(geom) as ymax from (select st_srid(rast) srid, st_extent(rast::geometry) geom, max(ST_NumBands(rast)) nbband from mib_postgis.gridcoverage_ cdsm75 group by st_srid(rast)) foo; srid | nbband | xmin | xmax | ymin |* ymax * ------+--------+-------------------+-------------------+------------------+------------------ 4617 | 1 | -139.500104166667 | -52.0001041666667 | 41.5001041666667 | 60.0001041666667 (1 row) Time: 153033.599 ms I'm wondering how I could avoid this SQL to be performed on each call, since it is consuming a large amount of the request processing time and values are always the same. See my current mapfile definition: MAP ... EXTENT -139.500104166667 41.5001041666667 -52.0001041666667 60.0001041666667 SIZE 1150 1350 MAXSIZE 20000 UNITS DD ... LAYER NAME cdsm GROUP cdsm METADATA "wcs_label" "cdsm" ### required "wcs_rangeset_name" "Range 1" ### required "wcs_rangeset_label" "My Label" ### required "wcs_extent" "-139.500104166667 41.5001041666667 -52.0001041666667 60.0001041666667" "wcs_resolution" "0.000208333333333 0.000208333333333" END TYPE RASTER STATUS ON PROCESSING "NODATA=255" DATA "PG:host=hostname port=portnumber dbname='dbname' user='username' password='passwd' schema='schema' table='gridcoverage_cdsm75' mode='2'" PROJECTION "init=epsg:4617" END END ... END Is it something that should be fixed at database level. Many thanks for any valuable input. J-F *Jean-François Bourgon* Ressources naturelles Canada | Natural Resources Canada
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