Update random() usage so ranges are inclusive/exclusive as required.

bmomjian · bmomjian · commit 59bb147353ba · 2006-02-03T12:45:47.000Z
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.90 2005/11/22 18:17:08 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.91 2006/02/03 12:45:47 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -927,18 +927,11 @@ acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
 	return numrows;
 }
 
-/* Select a random value R uniformly distributed in 0 < R < 1 */
+/* Select a random value R uniformly distributed in (0 - 1) */
 static double
 random_fract(void)
 {
-	long		z;
-
-	/* random() can produce endpoint values, try again if so */
-	do
-	{
-		z = random();
-	} while (z <= 0 || z >= MAX_RANDOM_VALUE);
-	return (double) z / (double) MAX_RANDOM_VALUE;
+	return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);
 }
 
 /*
diff --git a/src/backend/storage/lmgr/s_lock.c b/src/backend/storage/lmgr/s_lock.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/lmgr/s_lock.c,v 1.41 2005/11/22 18:17:21 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/lmgr/s_lock.c,v 1.42 2006/02/03 12:45:47 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -120,7 +120,7 @@ s_lock(volatile slock_t *lock, const char *file, int line)
 
 			/* increase delay by a random fraction between 1X and 2X */
 			cur_delay += (int) (cur_delay *
-				  (((double) random()) / ((double) MAX_RANDOM_VALUE)) + 0.5);
+				  ((double) random() / (double) MAX_RANDOM_VALUE) + 0.5);
 			/* wrap back to minimum delay when max is exceeded */
 			if (cur_delay > MAX_DELAY_MSEC)
 				cur_delay = MIN_DELAY_MSEC;
diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.119 2005/12/02 02:49:11 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/float.c,v 1.120 2006/02/03 12:45:47 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1833,8 +1833,8 @@ drandom(PG_FUNCTION_ARGS)
 {
 	float8		result;
 
-	/* result 0.0-1.0 */
-	result = ((double) random()) / ((double) MAX_RANDOM_VALUE);
+	/* result [0.0 - 1.0) */
+	result = (double) random() / ((double) MAX_RANDOM_VALUE + 1);
 
 	PG_RETURN_FLOAT8(result);
 }
diff --git a/src/include/optimizer/geqo_random.h b/src/include/optimizer/geqo_random.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/geqo_random.h,v 1.16 2004/12/31 22:03:36 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/geqo_random.h,v 1.17 2006/02/03 12:45:47 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -28,7 +28,7 @@
 
 /* geqo_rand returns a random float value between 0 and 1 inclusive */
 
-#define geqo_rand() (((double) random()) / ((double) MAX_RANDOM_VALUE))
+#define geqo_rand() ((double) random() / (double) MAX_RANDOM_VALUE)
 
 /* geqo_randint returns integer value between lower and upper inclusive */
 

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.90 2005/11/22 18:17:08 momjian Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.91 2006/02/03 12:45:47 momjian Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -927,18 +927,11 @@ acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,`
`927`	`927`	`return numrows;`
`928`	`928`	`}`
`929`	`929`
`930`		`-/* Select a random value R uniformly distributed in 0 < R < 1 */`
	`930`	`+/* Select a random value R uniformly distributed in (0 - 1) */`
`931`	`931`	`static double`
`932`	`932`	`random_fract(void)`
`933`	`933`	`{`
`934`		`- long z;`
`935`		`-`
`936`		`- /* random() can produce endpoint values, try again if so */`
`937`		`- do`
`938`		`- {`
`939`		`- z = random();`
`940`		`- } while (z <= 0 \|\| z >= MAX_RANDOM_VALUE);`
`941`		`- return (double) z / (double) MAX_RANDOM_VALUE;`
	`934`	`+ return ((double) random() + 1) / ((double) MAX_RANDOM_VALUE + 2);`
`942`	`935`	`}`
`943`	`936`
`944`	`937`	`/*`
Original file line number	Diff line number	Diff line change
`@@ -9,7 +9,7 @@`
`9`	`9`	`*`
`10`	`10`	`*`
`11`	`11`	`* IDENTIFICATION`
`12`		`- * $PostgreSQL: pgsql/src/backend/storage/lmgr/s_lock.c,v 1.41 2005/11/22 18:17:21 momjian Exp $`
	`12`	`+ * $PostgreSQL: pgsql/src/backend/storage/lmgr/s_lock.c,v 1.42 2006/02/03 12:45:47 momjian Exp $`
`13`	`13`	`*`
`14`	`14`	`*-------------------------------------------------------------------------`
`15`	`15`	`*/`
`@@ -120,7 +120,7 @@ s_lock(volatile slock_t lock, const char file, int line)`
`120`	`120`
`121`	`121`	`/* increase delay by a random fraction between 1X and 2X */`
`122`	`122`	`cur_delay += (int) (cur_delay *`
`123`		`- (((double) random()) / ((double) MAX_RANDOM_VALUE)) + 0.5);`
	`123`	`+ ((double) random() / (double) MAX_RANDOM_VALUE) + 0.5);`
`124`	`124`	`/* wrap back to minimum delay when max is exceeded */`
`125`	`125`	`if (cur_delay > MAX_DELAY_MSEC)`
`126`	`126`	`cur_delay = MIN_DELAY_MSEC;`
Original file line number	Diff line number	Diff line change
`@@ -6,7 +6,7 @@`
`6`	`6`	`* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group`
`7`	`7`	`* Portions Copyright (c) 1994, Regents of the University of California`
`8`	`8`	`*`
`9`		`- * $PostgreSQL: pgsql/src/include/optimizer/geqo_random.h,v 1.16 2004/12/31 22:03:36 pgsql Exp $`
	`9`	`+ * $PostgreSQL: pgsql/src/include/optimizer/geqo_random.h,v 1.17 2006/02/03 12:45:47 momjian Exp $`
`10`	`10`	`*`
`11`	`11`	`*-------------------------------------------------------------------------`
`12`	`12`	`*/`
`@@ -28,7 +28,7 @@`
`28`	`28`
`29`	`29`	`/* geqo_rand returns a random float value between 0 and 1 inclusive */`
`30`	`30`
`31`		`-#define geqo_rand() (((double) random()) / ((double) MAX_RANDOM_VALUE))`
	`31`	`+#define geqo_rand() ((double) random() / (double) MAX_RANDOM_VALUE)`
`32`	`32`
`33`	`33`	`/* geqo_randint returns integer value between lower and upper inclusive */`
`34`	`34`