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MDEV-15926 MEDIUMINT returns wrong I_S attributes

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Problem:

The logic in store_column_type() with a switch on field type was
hard to follow. The part for MEDIUMINT (MYSQL_TYPE_INT24) was not correct.
It erroneously calculated the precision of MEDIUMINT UNSIGNED
as 7 instead of 8.

A similar hard-to-follow switch doing some type specific calculations
resided in adjust_max_effective_column_length(). It was also wrong for
MEDIUMINT (reported as a separate issue in MDEV-15946).

Solution:

1. Introducing a new class Information_schema_numeric_attributes
2. Adding a new virtual method Field::information_schema_numeric_attributes()
3. Splitting the logic in store_column_type() into virtual
   implementations of information_schema_numeric_attributes().
4. In order to avoid adding duplicate code for the integer data types,
   adding a new virtual method Field_int::numeric_precision(),
   which returns the number of digits.

Additional changes:

1. Adding the "const" qualifier to Field::max_display_length()

2. Moving the code from adjust_max_effective_column_length()
  directly to Field::max_display_length().
  There was no any sense to have two implementations:
  - a set of wrong virtual implementations for Field_xxx::max_display_length()
  - additional code in adjust_max_effective_column_length() fixing
    bad results of Field_xxx::max_display_length()
  This change is safe:
  - The code using Field::max_display_length()
    in field.cc, sql_show.cc, sql_type.cc is not affected.
  - The code in rpl_utility.cc is also not affected.
    See a new DBUG_ASSSERT and new comments explaining why.

  In the new reduction, Field_xxx::max_display_length() returns
  correct results for all integer types (except MEDIUMINT, see below).

  Putting implementations of numeric_precision() and max_display_length()
  near each other in field.h made the logic much clearer and thus
  helped to reveal bad results for Field_medium::max_display_length(),
  which returns 9 instead of 8 for signed MEDIUMINT fields.
  This problem will be addressed separately (MDEV-15946).

Note, this change is also useful for pluggable data types (see MDEV-4912),
as now a user defined Field_xxx has a way to control what's returned
in INFORMATION_SCHEMA.COLUMNS.NUMERIC_PRECISION and
INFORMATION_SCHEMA.COLUMNS.NUMERIC_SCALE by implementing
a desired behavior in Field_xxx::information_schema_numeric_attributes().
This commit is contained in:
Alexander Barkov
2018-04-20 18:11:27 +04:00
parent 38c799c9a5
commit 9aaf62d058
11 changed files with 224 additions and 95 deletions
Download Patch File Download Diff File Expand all files Collapse all files

126
sql/field.h
View File

@ -1116,6 +1116,11 @@ public:
memcpy(ptr, val, len);
}
virtual uint decimals() const { return 0; }
virtual Information_schema_numeric_attributes
information_schema_numeric_attributes() const
{
return Information_schema_numeric_attributes();
}
/*
Caller beware: sql_type can change str.Ptr, so check
ptr() to see if it changed if you are using your own buffer
@ -1390,8 +1395,7 @@ public:
}
/* maximum possible display length */
virtual uint32 max_display_length()= 0;
virtual uint32 max_display_length() const= 0;
/**
Whether a field being created is compatible with a existing one.
@ -1726,7 +1730,7 @@ public:
CHARSET_INFO *charset(void) const { return field_charset; }
enum Derivation derivation(void) const { return field_derivation; }
bool binary() const { return field_charset == &my_charset_bin; }
uint32 max_display_length() { return field_length; }
uint32 max_display_length() const { return field_length; }
friend class Create_field;
my_decimal *val_decimal(my_decimal *);
bool val_bool() { return val_real() != 0e0; }
@ -1817,6 +1821,13 @@ public:
{
return do_field_real;
}
Information_schema_numeric_attributes
information_schema_numeric_attributes() const
{
return dec == NOT_FIXED_DEC ?
Information_schema_numeric_attributes(field_length) :
Information_schema_numeric_attributes(field_length, dec);
}
int save_in_field(Field *to) { return to->store(val_real()); }
bool memcpy_field_possible(const Field *from) const
{
@ -1833,7 +1844,7 @@ public:
bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
my_decimal *val_decimal(my_decimal *);
bool val_bool() { return val_real() != 0e0; }
uint32 max_display_length() { return field_length; }
uint32 max_display_length() const { return field_length; }
uint size_of() const { return sizeof(*this); }
Item *get_equal_const_item(THD *thd, const Context &ctx, Item *const_item);
};
@ -1852,6 +1863,12 @@ public:
const Type_handler *type_handler() const { return &type_handler_olddecimal; }
enum ha_base_keytype key_type() const
{ return zerofill ? HA_KEYTYPE_BINARY : HA_KEYTYPE_NUM; }
Information_schema_numeric_attributes
information_schema_numeric_attributes() const
{
uint tmp= dec ? 2 : 1; // The sign and the decimal point
return Information_schema_numeric_attributes(field_length - tmp, dec);
}
Copy_func *get_copy_func(const Field *from) const
{
return eq_def(from) ? get_identical_copy_func() : do_field_string;
@ -1936,7 +1953,12 @@ public:
void sort_string(uchar *buff, uint length);
bool zero_pack() const { return 0; }
void sql_type(String &str) const;
uint32 max_display_length() { return field_length; }
uint32 max_display_length() const { return field_length; }
Information_schema_numeric_attributes
information_schema_numeric_attributes() const
{
return Information_schema_numeric_attributes(precision, dec);
}
uint size_of() const { return sizeof(*this); }
uint32 pack_length() const { return (uint32) bin_size; }
uint pack_length_from_metadata(uint field_metadata);
@ -1954,6 +1976,7 @@ class Field_int :public Field_num
protected:
String *val_str_from_long(String *val_buffer, uint max_char_length,
int radix, long nr);
uint32 sign_length() const { return (flags & UNSIGNED_FLAG) ? 0 : 1; }
public:
Field_int(uchar *ptr_arg, uint32 len_arg, uchar *null_ptr_arg,
uchar null_bit_arg, enum utype unireg_check_arg,
@ -1966,6 +1989,12 @@ public:
bool val_bool() { return val_int() != 0; }
int store_time_dec(const MYSQL_TIME *ltime, uint dec);
bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
virtual uint numeric_precision() const= 0;
Information_schema_numeric_attributes
information_schema_numeric_attributes() const
{
return Information_schema_numeric_attributes(numeric_precision(), 0);
}
};
@ -1994,7 +2023,18 @@ public:
void sort_string(uchar *buff,uint length);
uint32 pack_length() const { return 1; }
void sql_type(String &str) const;
uint32 max_display_length() { return 4; }
/*
SIGNED: -128..127 digits=3 nchars=4
UNDIGNED: 0..255 digits=3 nchars=3
*/
uint numeric_precision() const
{
return MAX_TINYINT_WIDTH;
}
uint32 max_display_length() const
{
return MAX_TINYINT_WIDTH + sign_length();
}
virtual uchar *pack(uchar* to, const uchar *from, uint max_length)
{
@ -2044,7 +2084,18 @@ public:
void sort_string(uchar *buff,uint length);
uint32 pack_length() const { return 2; }
void sql_type(String &str) const;
uint32 max_display_length() { return 6; }
/*
SIGNED: -32768..32767 digits=5 nchars=6
UNDIGNED: 0..65535 digits=5 nchars=5
*/
uint numeric_precision() const
{
return MAX_SMALLINT_WIDTH;
}
uint32 max_display_length() const
{
return MAX_SMALLINT_WIDTH + sign_length();
}
virtual uchar *pack(uchar* to, const uchar *from, uint max_length)
{ return pack_int16(to, from); }
@ -2079,7 +2130,21 @@ public:
void sort_string(uchar *buff,uint length);
uint32 pack_length() const { return 3; }
void sql_type(String &str) const;
uint32 max_display_length() { return 8; }
/*
MEDIUMINT has a different number of digits for signed and unsigned:
MEDIUMINT SIGNED: -8388608 .. 8388607 digits=7 char_length=8
MEDIUMINT UNSIGNED 0 .. 16777215 digits=8 char_length=8
*/
uint numeric_precision() const
{
uint ndigits= MAX_MEDIUMINT_WIDTH - 1 + MY_TEST(flags & UNSIGNED_FLAG);
return ndigits;
}
uint32 max_display_length() const
{
// Looks too long for SIGNED: See MDEV-15946
return MAX_MEDIUMINT_WIDTH + sign_length();
}
virtual uchar *pack(uchar* to, const uchar *from, uint max_length)
{
@ -2119,7 +2184,18 @@ public:
void sort_string(uchar *buff,uint length);
uint32 pack_length() const { return 4; }
void sql_type(String &str) const;
uint32 max_display_length() { return MY_INT32_NUM_DECIMAL_DIGITS; }
/*
SIGNED: -2147483648..2147483647 digits=10 nchars=11
UNSIGNED: 0..4294967295 digits=10 nchars=10
*/
uint numeric_precision() const
{
return MAX_INT_WIDTH;
}
uint32 max_display_length() const
{
return MAX_INT_WIDTH + sign_length();
}
virtual uchar *pack(uchar* to, const uchar *from,
uint max_length __attribute__((unused)))
{
@ -2169,7 +2245,15 @@ public:
void sort_string(uchar *buff,uint length);
uint32 pack_length() const { return 8; }
void sql_type(String &str) const;
uint32 max_display_length() { return 20; }
/*
SIGNED: -9223372036854775808..9223372036854775807 digits=19 nchars=20
UNSIGNED: 0..18446744073709551615 digits=20 nchars=20
*/
uint numeric_precision() const
{
return MAX_BIGINT_WIDTH - sign_length();
}
uint32 max_display_length() const { return MAX_BIGINT_WIDTH; }
virtual uchar *pack(uchar* to, const uchar *from,
uint max_length __attribute__((unused)))
{
@ -2361,7 +2445,7 @@ public:
uint32 pack_length() const { return 0; }
void sql_type(String &str) const;
uint size_of() const { return sizeof(*this); }
uint32 max_display_length() { return 4; }
uint32 max_display_length() const { return 4; }
void move_field_offset(my_ptrdiff_t ptr_diff) {}
bool can_optimize_keypart_ref(const Item_bool_func *cond,
const Item *item) const
@ -2400,7 +2484,7 @@ public:
return to->store_time_dec(&ltime, decimals());
}
bool memcpy_field_possible(const Field *from) const;
uint32 max_display_length() { return field_length; }
uint32 max_display_length() const { return field_length; }
bool str_needs_quotes() { return TRUE; }
enum Derivation derivation(void) const { return DERIVATION_NUMERIC; }
uint repertoire(void) const { return MY_REPERTOIRE_NUMERIC; }
@ -2700,7 +2784,12 @@ public:
String *val_str(String*,String *);
bool get_date(MYSQL_TIME *ltime, ulonglong fuzzydate);
bool send_binary(Protocol *protocol);
uint32 max_display_length() { return field_length; }
Information_schema_numeric_attributes
information_schema_numeric_attributes() const
{
return Information_schema_numeric_attributes();
}
uint32 max_display_length() const { return field_length; }
void sql_type(String &str) const;
};
@ -3355,7 +3444,7 @@ private:
Field_varstring::sql_type(str);
str.append(STRING_WITH_LEN(" /*!100301 COMPRESSED*/"));
}
uint32 max_display_length() { return field_length - 1; }
uint32 max_display_length() const { return field_length - 1; }
int cmp_max(const uchar *a_ptr, const uchar *b_ptr, uint max_len);
/*
@ -3635,7 +3724,7 @@ public:
uint size_of() const { return sizeof(*this); }
bool has_charset(void) const
{ return charset() == &my_charset_bin ? FALSE : TRUE; }
uint32 max_display_length();
uint32 max_display_length() const;
uint32 char_length() const;
uint is_equal(Create_field *new_field);
private:
@ -3915,7 +4004,12 @@ public:
enum ha_base_keytype key_type() const { return HA_KEYTYPE_BIT; }
uint32 key_length() const { return (uint32) (field_length + 7) / 8; }
uint32 max_data_length() const { return (field_length + 7) / 8; }
uint32 max_display_length() { return field_length; }
uint32 max_display_length() const { return field_length; }
Information_schema_numeric_attributes
information_schema_numeric_attributes() const
{
return Information_schema_numeric_attributes(field_length);
}
uint size_of() const { return sizeof(*this); }
int reset(void) {
bzero(ptr, bytes_in_rec);