From faad73550c157388ffb7b1606e3f896ed7b276ac Mon Sep 17 00:00:00 2001 From: unknown Date: Wed, 31 Jan 2007 09:51:05 +0400 Subject: fix for bug #19690: ORDER BY eliminates rows from the result Depending on the queries we use different data processing methods and can lose some data in case of double (and decimal in 4.1) fields. The fix consists of two parts: 1. double comparison changed, now double a is equal to double b if (a-b) is less than 5*0.1^(1 + max(a->decimals, b->decimals)). For example, if a->decimals==1, b->decimals==2, a==b if (a-b)<0.005 2. if we use a temporary table, store double values there as is to avoid any data conversion (rounding). mysql-test/r/type_float.result: fix for bug #19690: ORDER BY eliminates rows from the result - test result mysql-test/t/type_float.test: fix for bug #19690: ORDER BY eliminates rows from the result - test case sql/field.cc: fix for bug #19690: ORDER BY eliminates rows from the result - use not_fixed flag instead of dec to check bounds. sql/field.h: fix for bug #19690: ORDER BY eliminates rows from the result - Field_Double::not_fixed flag introduced, which is set if dec == NOT_FIXED_DEC and is used in the ::store() to check bounds. - new constructor introduced (with not_fixed_arg parameter). sql/init.cc: fix for bug #19690: ORDER BY eliminates rows from the result - fill log_01[] array with 0.1 powers. sql/item_cmpfunc.cc: fix for bug #19690: ORDER BY eliminates rows from the result - compare_real_fixed() and compare_e_real_fixed() introduced, they consider double a == double b if a-b is less than 'precision', 'precision' is set to 5*0.1^(1 + max(a->decimals, b->decimals)), for example, if a->decimals==1, b->decimals==2, 'precision' is 0.005 - use the above functions if both arguments are fixed. sql/item_cmpfunc.h: fix for bug #19690: ORDER BY eliminates rows from the result - Arg_comparator::presision introduced. - Arg_comparator::compare_real_fixed(), Arg_comparator::compare_e_real_fixed() introduced. sql/mysql_priv.h: fix for bug #19690: ORDER BY eliminates rows from the result - log_01 array of 0.1 powers added. sql/mysqld.cc: fix for bug #19690: ORDER BY eliminates rows from the result - log_01 array of 0.1 powers added. sql/sql_select.cc: fix for bug #19690: ORDER BY eliminates rows from the result - if we create double field in a temporary table, set not_fixed flag (use proper constructor) to avoid data conversion in the Field_double::store(). Otherwise we can lose some data. --- sql/field.h | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'sql/field.h') diff --git a/sql/field.h b/sql/field.h index e4991ba1961..b10d950163c 100644 --- a/sql/field.h +++ b/sql/field.h @@ -616,6 +616,7 @@ public: class Field_double :public Field_num { public: + my_bool not_fixed; Field_double(char *ptr_arg, uint32 len_arg, uchar *null_ptr_arg, uchar null_bit_arg, enum utype unireg_check_arg, const char *field_name_arg, @@ -623,12 +624,20 @@ public: uint8 dec_arg,bool zero_arg,bool unsigned_arg) :Field_num(ptr_arg, len_arg, null_ptr_arg, null_bit_arg, unireg_check_arg, field_name_arg, table_arg, - dec_arg, zero_arg,unsigned_arg) + dec_arg, zero_arg, unsigned_arg), + not_fixed(dec_arg >= NOT_FIXED_DEC) {} Field_double(uint32 len_arg, bool maybe_null_arg, const char *field_name_arg, struct st_table *table_arg, uint8 dec_arg) - :Field_num((char*) 0, len_arg, maybe_null_arg ? (uchar*) "": 0, (uint) 0, - NONE, field_name_arg, table_arg,dec_arg,0,0) + :Field_num((char *) 0, len_arg, maybe_null_arg ? (uchar *) "" : 0, (uint) 0, + NONE, field_name_arg, table_arg,dec_arg, 0, 0), + not_fixed(dec_arg >= NOT_FIXED_DEC) + {} + Field_double(uint32 len_arg, bool maybe_null_arg, const char *field_name_arg, + struct st_table *table_arg, uint8 dec_arg, my_bool not_fixed_srg) + :Field_num((char *) 0, len_arg, maybe_null_arg ? (uchar *) "" : 0, (uint) 0, + NONE, field_name_arg, table_arg, dec_arg, 0, 0), + not_fixed(not_fixed_srg) {} enum_field_types type() const { return FIELD_TYPE_DOUBLE;} enum ha_base_keytype key_type() const { return HA_KEYTYPE_DOUBLE; } -- cgit v1.2.1