From dd7fa1d2280b45d13765577b74b2f394a6ee62dd Mon Sep 17 00:00:00 2001 From: Alexey Kopytov Date: Fri, 3 Jul 2009 11:41:19 +0400 Subject: Bug #45262: Bad effects with CREATE TABLE and DECIMAL Using DECIMAL constants with more than 65 digits in CREATE TABLE ... SELECT led to bogus errors in release builds or assertion failures in debug builds. The problem was in inconsistency in how DECIMAL constants and fields are handled internally. We allow arbitrarily long DECIMAL constants, whereas DECIMAL(M,D) columns are limited to M<=65 and D<=30. my_decimal_precision_to_length() was used in both Item and Field code and truncated precision to DECIMAL_MAX_PRECISION when calculating value length without adjusting precision and decimals. As a result, a DECIMAL constant with more than 65 digits ended up having length less than precision or decimals which led to assertion failures. Fixed by modifying my_decimal_precision_to_length() so that precision is truncated to DECIMAL_MAX_PRECISION only for Field object which is indicated by the new 'truncate' parameter. Another inconsistency fixed by this patch is how DECIMAL constants and expressions are handled for CREATE ... SELECT. create_tmp_field_from_item() (which is used for constants) was changed as a part of the bugfix for bug #24907 to handle long DECIMAL constants gracefully. Item_func::tmp_table_field() (which is used for expressions) on the other hand was still using a simplistic approach when creating a Field_new_decimal from a DECIMAL expression. mysql-test/r/type_newdecimal.result: Added a test case for bug #45262. mysql-test/t/type_newdecimal.test: Added a test case for bug #45262. sql/item.cc: Use the new 'truncate' parameter in my_decimal_precision_to_length(). sql/item_cmpfunc.cc: Use the new 'truncate' parameter in my_decimal_precision_to_length(). sql/item_func.cc: 1. Use the new 'truncate' parameter in my_decimal_precision_to_length(). 2. Do not truncate decimal precision to DECIMAL_MAX_PRECISION for additive expressions involving long DECIMAL constants. 3. Fixed an incosistency in how DECIMAL constants and expressions are handled for CREATE ... SELECT. sql/item_func.h: Use the new 'truncate' parameter in my_decimal_precision_to_length(). sql/item_sum.cc: Use the new 'truncate' parameter in my_decimal_precision_to_length(). sql/my_decimal.h: Do not truncate precision to DECIMAL_MAX_PRECISION when calculating length in my_decimal_precision_to_length() if 'truncate' parameter is FALSE. sql/sql_select.cc: 1. Use the new 'truncate' parameter in my_decimal_precision_to_length(). 2. Use a more correct logic when adjusting value's length. --- sql/my_decimal.h | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'sql/my_decimal.h') diff --git a/sql/my_decimal.h b/sql/my_decimal.h index 6a0d05921ec..ed1cffdccc5 100644 --- a/sql/my_decimal.h +++ b/sql/my_decimal.h @@ -170,6 +170,19 @@ inline uint my_decimal_length_to_precision(uint length, uint scale, (unsigned_flag || !length ? 0:1)); } +inline uint32 my_decimal_precision_to_length_no_truncation(uint precision, + uint8 scale, + bool unsigned_flag) +{ + /* + When precision is 0 it means that original length was also 0. Thus + unsigned_flag is ignored in this case. + */ + DBUG_ASSERT(precision || !scale); + return (uint32)(precision + (scale > 0 ? 1 : 0) + + (unsigned_flag || !precision ? 0 : 1)); +} + inline uint32 my_decimal_precision_to_length(uint precision, uint8 scale, bool unsigned_flag) { @@ -179,8 +192,8 @@ inline uint32 my_decimal_precision_to_length(uint precision, uint8 scale, */ DBUG_ASSERT(precision || !scale); set_if_smaller(precision, DECIMAL_MAX_PRECISION); - return (uint32)(precision + (scale>0 ? 1:0) + - (unsigned_flag || !precision ? 0:1)); + return my_decimal_precision_to_length_no_truncation(precision, scale, + unsigned_flag); } inline -- cgit v1.2.1