bk commit into 5.0 tree (ramil:1.2466) BUG#24558

[ramil]

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5.0 repository of ram. When ram does a push these changes will
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ChangeSet@stripped, 2007-03-15 12:06:06+04:00, ramil@stripped +3 -0
  Fix for bug #24558: Increasing decimal column length causes data loss
  
  Altering to a decimal field we get double value then store it 
  that may cause data loss. 
  Fix: use store_decimal() instead.
  

  mysql-test/r/type_newdecimal.result@stripped, 2007-03-15 12:06:05+04:00, ramil@stripped +8
-0
    Fix for bug #24558: Increasing decimal column length causes data loss
      - test result.

  mysql-test/t/type_newdecimal.test@stripped, 2007-03-15 12:06:05+04:00, ramil@stripped +11
-0
    Fix for bug #24558: Increasing decimal column length causes data loss
      - test case.

  sql/field_conv.cc@stripped, 2007-03-15 12:06:05+04:00, ramil@stripped +9 -0
    Fix for bug #24558: Increasing decimal column length causes data loss
      - if target field's result type is DECIMAL_RESULT
        use store_decimal(val_decimal()) in order not to loss data.

# 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:	ramil
# Host:	ramil.myoffice.izhnet.ru
# Root:	/home/ram/work/b24558/b24558.5.0

--- 1.61/sql/field_conv.cc	2007-03-15 12:06:11 +04:00
+++ 1.62/sql/field_conv.cc	2007-03-15 12:06:11 +04:00
@@ -337,6 +337,13 @@ static void do_field_real(Copy_field *co
 }
 
 
+static void do_field_decimal(Copy_field *copy)
+{
+  my_decimal value;
+  copy->to_field->store_decimal(copy->from_field->val_decimal(&value));
+}
+
+
 /*
   string copy for single byte characters set when to string is shorter than
   from string
@@ -581,6 +588,8 @@ void (*Copy_field::get_copy_func(Field *
     if (to->real_type() == FIELD_TYPE_BIT ||
         from->real_type() == FIELD_TYPE_BIT)
       return do_field_int;
+    if (to->result_type() == DECIMAL_RESULT)
+      return do_field_decimal;
     // Check if identical fields
     if (from->result_type() == STRING_RESULT)
     {

--- 1.43/mysql-test/r/type_newdecimal.result	2007-03-15 12:06:11 +04:00
+++ 1.44/mysql-test/r/type_newdecimal.result	2007-03-15 12:06:11 +04:00
@@ -1423,3 +1423,11 @@ cast(19999999999999999999 as unsigned)
 18446744073709551615
 Warnings:
 Error	1292	Truncated incorrect DECIMAL value: ''
+create table t1(a decimal(18));
+insert into t1 values(123456789012345678);
+alter table t1 modify column a decimal(19);
+select * from t1;
+a
+123456789012345678
+drop table t1;
+End of 5.0 tests

--- 1.42/mysql-test/t/type_newdecimal.test	2007-03-15 12:06:11 +04:00
+++ 1.43/mysql-test/t/type_newdecimal.test	2007-03-15 12:06:11 +04:00
@@ -1120,3 +1120,14 @@ drop table t1;
 #
 select cast(19999999999999999999 as unsigned);
 
+#
+# Bug #24558: Increasing decimal column length causes data loss
+#
+
+create table t1(a decimal(18));
+insert into t1 values(123456789012345678);
+alter table t1 modify column a decimal(19);
+select * from t1;
+drop table t1;
+
+--echo End of 5.0 tests