diff options
Diffstat (limited to 'src/backend/utils/adt/misc.c')
| -rw-r--r-- | src/backend/utils/adt/misc.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/src/backend/utils/adt/misc.c b/src/backend/utils/adt/misc.c index 7e3b8b167b9..7711cf7cddb 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 1.19 2000/06/05 07:28:52 tgl Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/adt/misc.c,v 1.20 2000/08/07 00:51:14 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -45,15 +45,18 @@ 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. + * 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. - * if X == 0, this will always return true; * * 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; @@ -61,7 +64,6 @@ static bool random_initialized = false; Datum oidrand(PG_FUNCTION_ARGS) { - /* XXX seems like we ought to be using the oid for something? */ #ifdef NOT_USED Oid o = PG_GETARG_OID(0); #endif @@ -96,7 +98,7 @@ oidsrand(PG_FUNCTION_ARGS) { int32 X = PG_GETARG_INT32(0); - srand(X); + srandom((unsigned int) X); random_initialized = true; PG_RETURN_BOOL(true); } |