From ab4f1947f3a2a135e7bb01bf06010c54ab5118f8 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 9 Jun 2007 15:52:38 +0000
Subject: [PATCH] Allow numeric_fac() to be interrupted, since it can take
 quite a while for large inputs.  Also cause it to error out immediately if
 the result will overflow, instead of grinding through a lot of calculation
 first. Per gripe from Jim Nasby.

---
 src/backend/utils/adt/numeric.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/backend/utils/adt/numeric.c b/src/backend/utils/adt/numeric.c
index 35b0221b85d..71a2e491868 100644
--- a/src/backend/utils/adt/numeric.c
+++ b/src/backend/utils/adt/numeric.c
@@ -14,7 +14,7 @@
  * Copyright (c) 1998-2006, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.96 2006/10/04 00:29:59 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/numeric.c,v 1.96.2.1 2007/06/09 15:52:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -28,6 +28,7 @@
 
 #include "catalog/pg_type.h"
 #include "libpq/pqformat.h"
+#include "miscadmin.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
 #include "utils/int8.h"
@@ -1416,6 +1417,11 @@ numeric_fac(PG_FUNCTION_ARGS)
 		res = make_result(&const_one);
 		PG_RETURN_NUMERIC(res);
 	}
+	/* Fail immediately if the result would overflow */
+	if (num > 32177)
+		ereport(ERROR,
+				(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
+				 errmsg("value overflows numeric format")));
 
 	init_var(&fact);
 	init_var(&result);
@@ -1424,6 +1430,9 @@ numeric_fac(PG_FUNCTION_ARGS)
 
 	for (num = num - 1; num > 1; num--)
 	{
+		/* this loop can take awhile, so allow it to be interrupted */
+		CHECK_FOR_INTERRUPTS();
+
 		int8_to_numericvar(num, &fact);
 
 		mul_var(&result, &fact, &result, 0);