binary_performance.sql

OReilly Oracle PL SQL Programming第4版源代码

/* File on web: binary_performance.sql */
DECLARE
   bd BINARY_DOUBLE;
   bd_area BINARY_DOUBLE;
   bd_sine BINARY_DOUBLE;
   nm NUMBER;
   nm_area NUMBER;
   nm_sine NUMBER;
   pi_bd BINARY_DOUBLE := 3.1415926536d;
   pi_nm NUMBER := 3.1415926536;
   bd_begin TIMESTAMP(9);
   bd_end TIMESTAMP(9);
   bd_wall_time INTERVAL DAY TO SECOND(9);
   nm_begin TIMESTAMP(9);
   nm_end TIMESTAMP(9);
   nm_wall_time INTERVAL DAY TO SECOND(9);
BEGIN
   --Compute area 5,000,000 times using binary doubles
   bd_begin := SYSTIMESTAMP;
   bd := 1d;
   LOOP
      bd_area := bd * bd * pi_bd;
      bd := bd + 1d;
      EXIT WHEN bd > 5000000;
   END LOOP;
   bd_end := SYSTIMESTAMP;

   --Compute area 5,000,000 times using NUMBERs
   nm_begin := SYSTIMESTAMP;
   nm := 1;
   LOOP
      nm_area := nm * nm * 2 * pi_nm;
      nm := nm + 1;
      EXIT WHEN nm > 5000000;
   END LOOP;
   nm_end := SYSTIMESTAMP;

   --Compute and display elapsed, wall-clock time
   bd_wall_time := bd_end - bd_begin;
   nm_wall_time := nm_end - nm_begin;
   DBMS_OUTPUT.PUT_LINE('BINARY_DOUBLE area = ' || bd_wall_time);
   DBMS_OUTPUT.PUT_LINE('NUMBER area = ' || nm_wall_time);

   --Compute sine 5,000,000 times using binary doubles
   bd_begin := SYSTIMESTAMP;
   bd := 1d;
   LOOP
      bd_sine := sin(bd);
      bd := bd + 1d;
      EXIT WHEN bd > 5000000;
   END LOOP;
   bd_end := SYSTIMESTAMP;

   --Compute sine 5,000,000 times using NUMBERs
   nm_begin := SYSTIMESTAMP;
   nm := 1;
   LOOP
      nm_sine := sin(nm);
      nm := nm + 1;
      EXIT WHEN nm > 5000000;
   END LOOP;
   nm_end := SYSTIMESTAMP;

   --Compute and display elapsed, wall-clock time for sine
   bd_wall_time := bd_end - bd_begin;
   nm_wall_time := nm_end - nm_begin;
   DBMS_OUTPUT.PUT_LINE('BINARY_DOUBLE sine = ' || bd_wall_time);
   DBMS_OUTPUT.PUT_LINE('NUMBER sine = ' || nm_wall_time);
END;