bzr commit into mysql-5.1 branch (sergey.glukhov:3646) Bug#11765923

[Sergey Glukhov]

#At file:///home/gluh/MySQL/mysql-5.1/ based on revid:sergey.glukhov@stripped

 3646 Sergey Glukhov	2011-04-11
      Bug#11765923  58937: MANY VALGRIND ERRORS AFTER GROUPING BY RESULT OF DECIMAL COLUMN FUNCTION
      When ROUND evaluates decimal result it uses Item::decimal
      value as fraction value for the result. In some cases
      Item::decimal is greater than real result fraction value
      and uninitialised memory of result(decimal) buffer can be
      used in further calculations.
      The fix is to use minimum between 
      decimal_value->frac and Item::decimals.
     @ mysql-test/r/func_math.result
        test case
     @ mysql-test/t/func_math.test
        test case
     @ sql/item_func.cc
        The fix is to use minimum between 
        decimal_value->frac and Item::decimals.

    modified:
      mysql-test/r/func_math.result
      mysql-test/t/func_math.test
      sql/item_func.cc
=== modified file 'mysql-test/r/func_math.result'
--- a/mysql-test/r/func_math.result	2011-03-28 08:35:50 +0000
+++ b/mysql-test/r/func_math.result	2011-04-11 09:22:44 +0000
@@ -518,4 +518,18 @@ CREATE TABLE t1 SELECT CEIL(LINESTRINGFR
 DROP TABLE t1;
 CREATE TABLE t1 SELECT FLOOR(LINESTRINGFROMWKB(1) DIV NULL);
 DROP TABLE t1;
+#
+# Bug#11765923  58937: MANY VALGRIND ERRORS AFTER GROUPING BY RESULT OF DECIMAL COLUMN FUNCTION
+#
+CREATE TABLE t1(f1 DECIMAL(22,1));
+INSERT INTO t1 VALUES (0),(1);
+SELECT ROUND(f1, f1) FROM t1;
+ROUND(f1, f1)
+0.0
+1.0
+SELECT ROUND(f1, f1) FROM t1 GROUP BY 1;
+ROUND(f1, f1)
+0.0
+1.0
+DROP TABLE t1;
 End of 5.1 tests

=== modified file 'mysql-test/t/func_math.test'
--- a/mysql-test/t/func_math.test	2011-03-28 08:35:50 +0000
+++ b/mysql-test/t/func_math.test	2011-04-11 09:22:44 +0000
@@ -333,4 +333,14 @@ DROP TABLE t1;
 CREATE TABLE t1 SELECT FLOOR(LINESTRINGFROMWKB(1) DIV NULL);
 DROP TABLE t1;
 
+--echo #
+--echo # Bug#11765923  58937: MANY VALGRIND ERRORS AFTER GROUPING BY RESULT OF DECIMAL COLUMN FUNCTION
+--echo #
+
+CREATE TABLE t1(f1 DECIMAL(22,1));
+INSERT INTO t1 VALUES (0),(1);
+SELECT ROUND(f1, f1) FROM t1;
+SELECT ROUND(f1, f1) FROM t1 GROUP BY 1;
+DROP TABLE t1;
+
 --echo End of 5.1 tests

=== modified file 'sql/item_func.cc'
--- a/sql/item_func.cc	2011-03-28 13:27:44 +0000
+++ b/sql/item_func.cc	2011-04-11 09:22:44 +0000
@@ -2123,7 +2123,7 @@ my_decimal *Item_func_round::decimal_op(
                      my_decimal_round(E_DEC_FATAL_ERROR, value, (int) dec,
                                       truncate, decimal_value) > 1))) 
   {
-    decimal_value->frac= decimals;
+    decimal_value->frac= min(decimal_value->frac, decimals);
     return decimal_value;
   }
   return 0;


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