Make selectivity routines cope gracefully with NaNs, infinities, and

NUMERIC values that are out of the range of 'double'.  Per trouble
report from Mike Quinn.

src/backend/utils/adt/numeric.c

@@ -5,7 +5,7 @@
  *
  *	1998 Jan Wieck
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/adt/numeric.c,v 1.44 2001/10/03 05:29:24 thomas Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/numeric.c,v 1.45 2001/10/13 23:32:33 tgl Exp $
  *
  * ----------
  */
@@ -1663,6 +1663,35 @@ numeric_float8(PG_FUNCTION_ARGS)
 }
 
 
+/* Convert numeric to float8; if out of range, return +/- HUGE_VAL */
+Datum
+numeric_float8_no_overflow(PG_FUNCTION_ARGS)
+{
+	Numeric		num = PG_GETARG_NUMERIC(0);
+	char	   *tmp;
+	double		val;
+	char	   *endptr;
+
+	if (NUMERIC_IS_NAN(num))
+		PG_RETURN_FLOAT8(NAN);
+
+	tmp = DatumGetCString(DirectFunctionCall1(numeric_out,
+											  NumericGetDatum(num)));
+
+	/* unlike float8in, we ignore ERANGE from strtod */
+	val = strtod(tmp, &endptr);
+	if (*endptr != '\0')
+	{
+		/* shouldn't happen ... */
+		elog(ERROR, "Bad float8 input format '%s'", tmp);
+	}
+
+	pfree(tmp);
+
+	PG_RETURN_FLOAT8(val);
+}
+
+
 Datum
 float4_numeric(PG_FUNCTION_ARGS)
 {

src/backend/utils/adt/selfuncs.c

@@ -15,7 +15,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.98 2001/10/03 18:25:59 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/selfuncs.c,v 1.99 2001/10/13 23:32:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -581,7 +581,18 @@ scalarineqsel(Query *root, Oid operator, bool isgt,
 						else if (val >= high)
 							binfrac = 1.0;
 						else
+						{
 							binfrac = (val - low) / (high - low);
+							/*
+							 * Watch out for the possibility that we got a NaN
+							 * or Infinity from the division.  This can happen
+							 * despite the previous checks, if for example
+							 * "low" is -Infinity.
+							 */
+							if (isnan(binfrac) ||
+								binfrac < 0.0 || binfrac > 1.0)
+								binfrac = 0.5;
+						}
 					}
 					else
 					{
@@ -1665,8 +1676,8 @@ icnlikejoinsel(PG_FUNCTION_ARGS)
  * subroutines in pg_type.
  *
  * All numeric datatypes are simply converted to their equivalent
- * "double" values.  XXX what about NUMERIC values that are outside
- * the range of "double"?
+ * "double" values.  (NUMERIC values that are outside the range of "double"
+ * are clamped to +/- HUGE_VAL.)
  *
  * String datatypes are converted by convert_string_to_scalar(),
  * which is explained below.  The reason why this routine deals with
@@ -1677,8 +1688,9 @@ icnlikejoinsel(PG_FUNCTION_ARGS)
  *
  * The several datatypes representing absolute times are all converted
  * to Timestamp, which is actually a double, and then we just use that
- * double value.  Note this will give bad results for the various "special"
- * values of Timestamp --- what can we do with those?
+ * double value.  Note this will give correct results even for the "special"
+ * values of Timestamp, since those are chosen to compare correctly;
+ * see timestamp_cmp.
  *
  * The several datatypes representing relative times (intervals) are all
  * converted to measurements expressed in seconds.
@@ -1793,8 +1805,10 @@ convert_numeric_to_scalar(Datum value, Oid typid)
 		case FLOAT8OID:
 			return (double) DatumGetFloat8(value);
 		case NUMERICOID:
-			return (double) DatumGetFloat8(DirectFunctionCall1(numeric_float8,
-															   value));
+			/* Note: out-of-range values will be clamped to +-HUGE_VAL */
+			return (double)
+				DatumGetFloat8(DirectFunctionCall1(numeric_float8_no_overflow,
+												   value));
 		case OIDOID:
 		case REGPROCOID:
 			/* we can treat OIDs as integers... */

src/include/utils/builtins.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: builtins.h,v 1.167 2001/10/13 16:34:08 tgl Exp $
+ * $Id: builtins.h,v 1.168 2001/10/13 23:32:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -553,6 +553,7 @@ extern Datum int2_numeric(PG_FUNCTION_ARGS);
 extern Datum numeric_int2(PG_FUNCTION_ARGS);
 extern Datum float8_numeric(PG_FUNCTION_ARGS);
 extern Datum numeric_float8(PG_FUNCTION_ARGS);
+extern Datum numeric_float8_no_overflow(PG_FUNCTION_ARGS);
 extern Datum float4_numeric(PG_FUNCTION_ARGS);
 extern Datum numeric_float4(PG_FUNCTION_ARGS);
 extern Datum numeric_accum(PG_FUNCTION_ARGS);