added patch from Mark Cave-Ayland that saves memory during histogram

calculations by using cursors instead of loading all the BOXs at once.

git-svn-id: http://svn.osgeo.org/postgis/trunk@231 b70326c6-7e19-0410-871a-916f4a2858ee

diff --git a/postgis_estimate.c b/postgis_estimate.c
index cead7fb67bc11addb304cae5b2e322ff948cdfcf..47c5fa3ab6401c22d3079dd59aa7a81cb126e045 100644 (file)
--- a/postgis_estimate.c
+++ b/postgis_estimate.c
@@ -302,6 +302,11 @@ Datum build_histogram2d(PG_FUNCTION_ARGS)
     int    sum_area_numb_new =0;
        int bump=0;
 
+       bool moredata;
+       void *SPIplan;
+       void *SPIportal;
+
+
     xmin = histo->xmin;
     ymin = histo->ymin;
     xmax = histo->xmax;
@@ -331,8 +336,8 @@ Datum build_histogram2d(PG_FUNCTION_ARGS)
                columnname = DatumGetCString(DirectFunctionCall1(textout,
                                                        PointerGetDatum(PG_GETARG_DATUM(2))));
 
-       //elog(NOTICE,"Start build_histogram2d with %i items already existing", sum_area_numb);
-       //elog(NOTICE,"table=\"%s\", column = \"%s\"", tablename, columnname);
+       elog(NOTICE,"Start build_histogram2d with %i items already existing", sum_area_numb);
+       elog(NOTICE,"table=\"%s\", column = \"%s\"", tablename, columnname);
 
 
                SPIcode = SPI_connect();
@@ -347,94 +352,119 @@ Datum build_histogram2d(PG_FUNCTION_ARGS)
 
                        sprintf(sql,"SELECT box(\"%s\") FROM \"%s\"",columnname,tablename);
                        //elog(NOTICE,"executing %s",sql);
+                       //SPIcode = SPI_exec(sql, 2147483640 ); // max signed int32
 
-                       SPIcode = SPI_exec(sql, 2147483640 ); // max signed int32
+                       SPIplan = SPI_prepare(sql, 0, NULL);
+                       if (SPIplan  == NULL)
+                       {
+                                       elog(ERROR,"build_histogram2d: couldnt create query plan via SPI");
+                                       PG_RETURN_NULL() ;
+                       }
 
-                       if (SPIcode  != SPI_OK_SELECT )
+                       SPIportal = SPI_cursor_open(NULL, SPIplan, NULL, NULL);
+                       if (SPIportal == NULL)
                        {
-                                       elog(ERROR,"build_histogram2d: couldnt execute sql via SPI");
+                                       elog(ERROR,"build_histogram2d: couldn't create cursor via SPI");
                                        PG_RETURN_NULL() ;
                        }
 
                        //elog(NOTICE,"processing %i records",SPI_processed);
+                       moredata = TRUE;
 
-                       tuptable = SPI_tuptable;
-                       tupdesc = SPI_tuptable->tupdesc;
-                       ntuples = SPI_processed;
+                       while (moredata==TRUE) {
 
-                       cell_area = ( (xmax-xmin)*(ymax-ymin)/(histo->boxesPerSide*histo->boxesPerSide) );
+                               SPI_cursor_fetch(SPIportal, TRUE, 50000);
 
-                       for (t=0;t<ntuples;t++)
-                       {
-                               tuple = tuptable->vals[t];
-                               datum = SPI_getbinval(tuple, tupdesc, 1, &isnull);
-                               if (!(isnull))
-                               {
-                                       box = (BOX *)DatumGetPointer(datum);
-                                       box_area = (box->high.x-box->low.x)*(box->high.y-box->low.y);
+                               tuptable = SPI_tuptable;
+                               tupdesc = SPI_tuptable->tupdesc;
+                               ntuples = SPI_processed;
 
-                                       sum_area_new += box_area;
-                                       sum_area_numb_new ++;
+                               if (ntuples > 0) {
 
-                                       if (box_area > cell_area )
-                                               box_area = cell_area;
-                                       if (box_area<0)
-                                           box_area =0;  // for precision!
+                                       cell_area = ( (xmax-xmin)*(ymax-ymin)/(histo->boxesPerSide*histo->boxesPerSide) );
 
-                                       //check to see which boxes this intersects
-                                       x_idx_min = (box->low.x-xmin)/(xmax-xmin)*histo->boxesPerSide;
-                                       if (x_idx_min <0)
-                                               x_idx_min = 0;
-                                       if (x_idx_min >= histo->boxesPerSide)
-                                               x_idx_min = histo->boxesPerSide-1;
-                                       y_idx_min = (box->low.y-ymin)/(ymax-ymin)*histo->boxesPerSide;
-                                       if (y_idx_min <0)
-                                               y_idx_min = 0;
-                                       if (y_idx_min >= histo->boxesPerSide)
-                                               y_idx_min = histo->boxesPerSide-1;
-
-                                       x_idx_max = (box->high.x-xmin)/(xmax-xmin)*histo->boxesPerSide;
-                                       if (x_idx_max <0)
-                                               x_idx_max = 0;
-                                       if (x_idx_max >= histo->boxesPerSide)
-                                               x_idx_max = histo->boxesPerSide-1;
-                                       y_idx_max = (box->high.y-ymin)/(ymax-ymin)*histo->boxesPerSide ;
-                                       if (y_idx_max <0)
-                                               y_idx_max = 0;
-                                       if (y_idx_max >= histo->boxesPerSide)
-                                               y_idx_max = histo->boxesPerSide-1;
-
-                                       //the {x,y}_idx_{min,max} define the grid squares that the box intersects
-                                       // if the area of the intersect between the box and the grid square > 5% of
-
-       //elog(NOTICE,"box is : (%.15g,%.15g to %.15g,%.15g)",box->low.x,box->low.y, box->high.x, box->high.y);
-//elog(NOTICE,"        search is in x: %i to %i   y: %i to %i",x_idx_min, x_idx_max, y_idx_min,y_idx_max);
-                                       for (y= y_idx_min; y<=y_idx_max;y++)
+                                       for (t=0;t<ntuples;t++)
                                        {
-                                               for (x=x_idx_min;x<= x_idx_max;x++)
+                                               tuple = tuptable->vals[t];
+                                               datum = SPI_getbinval(tuple, tupdesc, 1, &isnull);
+                                               if (!(isnull))
                                                {
-                                                               intersect_x = min(box->high.x, xmin+ (x+1) * (xmax-xmin)/histo->boxesPerSide ) -
-                                                                                       max(box->low.x, xmin+ x*(xmax-xmin)/histo->boxesPerSide ) ;
-                                                               intersect_y = min(box->high.y, ymin+ (y+1) * (ymax-ymin)/histo->boxesPerSide ) -
-                                                                                       max(box->low.y, ymin+ y*(ymax-ymin)/histo->boxesPerSide ) ;
-
-                                                                       // for a point, intersect_x=0, intersect_y=0, box_area =0
-//elog(NOTICE,"x=%i,y=%i, intersect_x= %.15g, intersect_y = %.15g",x,y,intersect_x,intersect_y);
-                                                               if ( (intersect_x>=0) && (intersect_y>=0) )
+                                                       box = (BOX *)DatumGetPointer(datum);
+                                                       box_area = (box->high.x-box->low.x)*(box->high.y-box->low.y);
+
+                                                       sum_area_new += box_area;
+                                                       sum_area_numb_new ++;
+
+                                                       if (box_area > cell_area )
+                                                               box_area = cell_area;
+                                                       if (box_area<0)
+                                                               box_area =0;  // for precision!
+
+                                                       //check to see which boxes this intersects
+                                                       x_idx_min = (box->low.x-xmin)/(xmax-xmin)*histo->boxesPerSide;
+                                                       if (x_idx_min <0)
+                                                               x_idx_min = 0;
+                                                       if (x_idx_min >= histo->boxesPerSide)
+                                                               x_idx_min = histo->boxesPerSide-1;
+                                                       y_idx_min = (box->low.y-ymin)/(ymax-ymin)*histo->boxesPerSide;
+                                                       if (y_idx_min <0)
+                                                               y_idx_min = 0;
+                                                       if (y_idx_min >= histo->boxesPerSide)
+                                                               y_idx_min = histo->boxesPerSide-1;
+
+                                                       x_idx_max = (box->high.x-xmin)/(xmax-xmin)*histo->boxesPerSide;
+                                                       if (x_idx_max <0)
+                                                               x_idx_max = 0;
+                                                       if (x_idx_max >= histo->boxesPerSide)
+                                                               x_idx_max = histo->boxesPerSide-1;
+                                                       y_idx_max = (box->high.y-ymin)/(ymax-ymin)*histo->boxesPerSide ;
+                                                       if (y_idx_max <0)
+                                                               y_idx_max = 0;
+                                                       if (y_idx_max >= histo->boxesPerSide)
+                                                               y_idx_max = histo->boxesPerSide-1;
+
+                                                       //the {x,y}_idx_{min,max} define the grid squares that the box intersects
+                                                       // if the area of the intersect between the box and the grid square > 5% of
+
+                       //elog(NOTICE,"box is : (%.15g,%.15g to %.15g,%.15g)",box->low.x,box->low.y, box->high.x, box->high.y);
+               //elog(NOTICE,"        search is in x: %i to %i   y: %i to %i",x_idx_min, x_idx_max, y_idx_min,y_idx_max);
+                                                       for (y= y_idx_min; y<=y_idx_max;y++)
+                                                       {
+                                                               for (x=x_idx_min;x<= x_idx_max;x++)
                                                                {
-                                                                       area_intersect = intersect_x*intersect_y;
-                                                                       if (area_intersect >= box_area*0.05)
-                                                                       {
-//elog(NOTICE,"bump");
-                                                                               bump++;
-                                                                               result->value[x+y*histo->boxesPerSide]++;
-                                                                       }
+                                                                               intersect_x = min(box->high.x, xmin+ (x+1) * (xmax-xmin)/histo->boxesPerSide ) -
+                                                                                                       max(box->low.x, xmin+ x*(xmax-xmin)/histo->boxesPerSide ) ;
+                                                                               intersect_y = min(box->high.y, ymin+ (y+1) * (ymax-ymin)/histo->boxesPerSide ) -
+                                                                                                       max(box->low.y, ymin+ y*(ymax-ymin)/histo->boxesPerSide ) ;
+
+                                                                                       // for a point, intersect_x=0, intersect_y=0, box_area =0
+               //elog(NOTICE,"x=%i,y=%i, intersect_x= %.15g, intersect_y = %.15g",x,y,intersect_x,intersect_y);
+                                                                               if ( (intersect_x>=0) && (intersect_y>=0) )
+                                                                               {
+                                                                                       area_intersect = intersect_x*intersect_y;
+                                                                                       if (area_intersect >= box_area*0.05)
+                                                                                       {
+               //elog(NOTICE,"bump");
+                                                                                               bump++;
+                                                                                               result->value[x+y*histo->boxesPerSide]++;
+                                                                                       }
+                                                                               }
                                                                }
-                                               }
-                                       }
+                                                       } // End of y
 
-                               }
-                       }
+                                               } // End isnull
+
+                                       } // End of for loop
+
+                               } else {
+                                               moredata = FALSE;
+                               } // End of if ntuples > 0
+
+                       } // End of while loop
+
+
+               // Close the cursor
+               SPI_cursor_close(SPIportal);
 
            SPIcode =SPI_finish();
            if (SPIcode  != SPI_OK_FINISH )