The "random" regression test uses a function called oidrand(), which

takes two parameters, an OID x and an integer y, and returns "true" with
probability 1/y (the OID argument is ignored). This can be useful -- for
example, it can be used to select a random sampling of the rows in a
table (which is what the "random" regression test uses it for).

This patch removes that function, because it was old and messy. The old
function had the following problems:

- it was undocumented

- it was poorly named

- it was designed to workaround an optimizer bug that no longer exists
(the OID argument is to ensure that the optimizer won't optimize away
calls to the function; AFAIK marking the function as 'volatile' suffices
nowadays)

- it used a different random-number generation technique than the other
PSRNG-related functions in the backend do (it called random() like they
do, but it had its own logic for setting a set and deciding when to
reseed the RNG).

Ok, this patch removes oidrand(), oidsrand(), and userfntest(), and
improves the SGML docs a little bit (un-commenting the setseed()
documentation).

Neil Conway

1 files changed, 1 insertions, 70 deletions

diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c
index 6b105fdef4d..1f85e4f4992 100644
--- a/src/backend/utils/adt/misc.c
+++ b/src/backend/utils/adt/misc.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/misc.c,v 1.27 2002/09/04 20:31:28 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/misc.c,v 1.28 2003/02/13 05:24:02 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -44,75 +44,6 @@ nonnullvalue(PG_FUNCTION_ARGS)
 }
 
 /*
- * oidrand (oid o, int4 X)-
- *	  Takes in an oid and a int4 X, and will return 'true' about 1/X of
- *	  the time.  If X == 0, this will always return true.
- *	  Useful for doing random sampling or subsetting.
- *
- * Example use:
- *	   select * from TEMP where oidrand(TEMP.oid, 10)
- * will return about 1/10 of the tuples in TEMP
- *
- * NOTE: the OID input is not used at all.	It is there just because of
- * an old optimizer bug: a qual expression containing no variables was
- * mistakenly assumed to be a constant.  Pretending to access the row's OID
- * prevented the optimizer from treating the oidrand() result as constant.
- */
-
-static bool random_initialized = false;
-
-Datum
-oidrand(PG_FUNCTION_ARGS)
-{
-#ifdef NOT_USED
-	Oid			o = PG_GETARG_OID(0);
-#endif
-	int32		X = PG_GETARG_INT32(1);
-	bool		result;
-
-	if (X == 0)
-		PG_RETURN_BOOL(true);
-
-	/*
-	 * We do this because the cancel key is actually a random, so we don't
-	 * want them to be able to request random numbers using our postmaster
-	 * seeded value.
-	 */
-	if (!random_initialized)
-	{
-		srandom((unsigned int) time(NULL));
-		random_initialized = true;
-	}
-
-	result = (random() % X == 0);
-	PG_RETURN_BOOL(result);
-}
-
-/*
-   oidsrand(int32 X) -
-	  seeds the random number generator
-	  always returns true
-*/
-Datum
-oidsrand(PG_FUNCTION_ARGS)
-{
-	int32		X = PG_GETARG_INT32(0);
-
-	srandom((unsigned int) X);
-	random_initialized = true;
-	PG_RETURN_BOOL(true);
-}
-
-
-Datum
-userfntest(PG_FUNCTION_ARGS)
-{
-	int32		i = PG_GETARG_INT32(0);
-
-	PG_RETURN_INT32(i);
-}
-
-/*
  * current_database()
  *	Expose the current database to the user
  */