From: Date: May 21 2007 7:22pm
Subject: bk commit into 5.0 tree (holyfoot:1.2490) BUG#27984
List-Archive: http://lists.mysql.com/commits/27090
X-Bug: 27984
Message-Id: <20070521172252.085E32C380B7@hfmain.localdomain>

Below is the list of changes that have just been committed into a local
5.0 repository of hf. When hf does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet@stripped, 2007-05-21 22:22:47+05:00, holyfoot@stripped +3 -0
  Bug #27984 Long Decimal Maths produces truncated results.
  decimal_round failed to perform a correct rounding 
  of a decimal number if its first nine digits were '9'.
  It just sets those digits to 0.

  mysql-test/r/type_newdecimal.result@stripped, 2007-05-21 22:22:46+05:00, holyfoot@stripped +3 -0
    Bug #27984 Long Decimal Maths produces truncated results.
    test result

  mysql-test/t/type_newdecimal.test@stripped, 2007-05-21 22:22:46+05:00, holyfoot@stripped +5 -0
    Bug #27984 Long Decimal Maths produces truncated results.
    test case

  strings/decimal.c@stripped, 2007-05-21 22:22:46+05:00, holyfoot@stripped +2 -1
    Bug #27984 Long Decimal Maths produces truncated results.
    when to == from we break the data if we do to->buf[0]=0
    So now doing this after the data is moved and only
    if we really need to set to->buf[0] to zero

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	holyfoot
# Host:	hfmain.(none)
# Root:	/home/hf/work/27984/my50-27984

--- 1.46/mysql-test/r/type_newdecimal.result	2007-05-21 22:22:51 +05:00
+++ 1.47/mysql-test/r/type_newdecimal.result	2007-05-21 22:22:51 +05:00
@@ -1465,4 +1465,7 @@ Error	1264	Out of range value adjusted f
 Error	1264	Out of range value adjusted for column 'cast(a as DECIMAL(3,2))' at row 1
 Error	1264	Out of range value adjusted for column 'cast(a as DECIMAL(3,2))' at row 1
 Error	1264	Out of range value adjusted for column 'cast(a as DECIMAL(3,2))' at row 1
+SELECT 1.000000000000 * 99.999999999998 / 100 a,1.000000000000 * (99.999999999998 / 100) b;
+a	b
+0.9999999999999800000000000000	0.9999999999999800000000000000
 End of 5.0 tests

--- 1.44/mysql-test/t/type_newdecimal.test	2007-05-21 22:22:51 +05:00
+++ 1.45/mysql-test/t/type_newdecimal.test	2007-05-21 22:22:51 +05:00
@@ -1149,4 +1149,9 @@ select cast(a as DECIMAL(3,2)), count(*)
   UNION select 12.1234
  ) t group by 1;
 
+#
+# Bug #27984 Long Decimal Maths produces truncated results 
+#
+
+SELECT 1.000000000000 * 99.999999999998 / 100 a,1.000000000000 * (99.999999999998 / 100) b;
 --echo End of 5.0 tests

--- 1.79/strings/decimal.c	2007-05-21 22:22:51 +05:00
+++ 1.80/strings/decimal.c	2007-05-21 22:22:51 +05:00
@@ -1517,9 +1517,10 @@ decimal_round(decimal_t *from, decimal_t
     dec1 *p0= buf0+intg0+max(frac1, frac0);
     dec1 *p1= buf1+intg1+max(frac1, frac0);
 
-    to->buf[0]= 0;
     while (buf0 < p0)
       *(--p1) = *(--p0);
+    if (unlikely(intg1 > intg0))
+      to->buf[0]= 0;
 
     intg0= intg1;
     buf0=to->buf;