Decimals with float, double and decimal now works the following way:
- DECIMAL_NOT_SPECIFIED is used when declaring DECIMALS without a firm number
of decimals. It's only used in asserts and my_decimal_int_part.
- FLOATING_POINT_DECIMALS (31) is used to mark that a FLOAT or DOUBLE
was defined without decimals. This is regarded as a floating point value.
- Max decimals allowed for FLOAT and DOUBLE is FLOATING_POINT_DECIMALS-1
- Clients assumes that float and double with decimals >= NOT_FIXED_DEC are
floating point values (no decimals)
- In the .frm decimals=FLOATING_POINT_DECIMALS are used to define
floating point for float and double (31, like before)
To ensure compatibility with old clients we do:
- When storing float and double, we change NOT_FIXED_DEC to
FLOATING_POINT_DECIMALS.
- When creating fields from .frm we change for float and double
FLOATING_POINT_DEC to NOT_FIXED_DEC
- When sending definition for a float/decimal field without decimals
to the client as part of a result set we convert NOT_FIXED_DEC to
FLOATING_POINT_DECIMALS.
- variance() and std() has changed to limit the decimals to
FLOATING_POINT_DECIMALS -1 to not get the double converted floating point.
(This was to preserve compatiblity)
- FLOAT and DOUBLE still have 30 as max number of decimals.
Bugs fixed:
variance() printed more decimals than we support for double values.
New behaviour:
- Strings now have 38 decimals instead of 30 when converted to decimal
- CREATE ... SELECT with a decimal with > 30 decimals will create a column
with a smaller range than before as we are trying to preserve the number of
decimals.
Other changes
- We are now using the obsolete bit FIELDFLAG_LEFT_FULLSCREEN to specify
decimals > 31
- NOT_FIXED_DEC is now declared in one place
- For clients, NOT_FIXED_DEC is always 31 (to ensure compatibility).
On the server NOT_FIXED_DEC is DECIMAL_NOT_SPECIFIED (39)
- AUTO_SEC_PART_DIGITS is taken from DECIMAL_NOT_SPECIFIED
- DOUBLE conversion functions are now using DECIMAL_NOT_SPECIFIED instead of
NOT_FIXED_DEC
Also fixes:
MDEV-9391 InnoDB does not produce warnings when doing WHERE int_column=varchar_column
MDEV-9337 ALTER from DECIMAL and INT to DATETIME returns a wrong result
MDEV-9340 Copying from INT/DOUBLE to ENUM is inconsistent
MDEV-9392 Copying from DECIMAL to YEAR is not consistent about warnings
NOT NULL constraint must be checked *after* the BEFORE triggers.
That is for INSERT and UPDATE statements even NOT NULL fields
must be able to store a NULL temporarily at least while
BEFORE INSERT/UPDATE triggers are running.
The following left in semi-improved state to keep patch size reasonable:
- Field operator new: left thd_alloc(current_thd)
- Sql_alloc operator new: left thd_alloc(thd_get_current_thd())
- Item_args constructors: left thd_alloc(thd)
- Item_func_interval::fix_length_and_dec(): no THD arg, have to call current_thd
- Item_func_dyncol_exists::val_int(): same
- Item_dyncol_get::val_str(): same
- Item_dyncol_get::val_int(): same
- Item_dyncol_get::val_real(): same
- Item_dyncol_get::val_decimal(): same
- Item_singlerow_subselect::fix_length_and_dec(): same
changes in query execution plans.
Fixed by introducing table->rpl_write_set which holds which columns should
be stored in the binary log.
Other things:
- Removed some not needed references to read_set and write_set to make
code really changing read_set and write_set easier to read
(in opt_range.cc)
- Added error handling of failed unpack_current_row()
- Added missing call to mark_columns_needed_for_insert() for DELAYED INSERT
- Removed not used functions in_read_set() and in_write_set()
- In rpl_record.cc, removed not used variable error
Issue:
-----
When a varchar column is used to fill the record in an
internal temporary table, the length of the string stored
in the column is not taken into account. Instead the
default length of packed data is used to copy with memmove.
This will cause valgrind issues since some bytes are
uninitialized.
SOLUTION:
---------
The solution is to take into account the length of the
string stored in the column while filling the record.
This fix is a backport of BUG#13389854.
from Item_bool_func::get_mm_leaf() into Field_xxx::can_optimize_range().
This reduces the total amount of virtual calls. Also, it's a prerequisite
change for the pluggable data types.
