Implementing methods:
- Field::val_time_packed()
- Field::val_datetime_packed()
- Item_field::val_datetime_packed(THD *thd);
- Item_field::val_time_packed(THD *thd);
to give a faster access to temporal packed longlong representation of a Field,
which is used in temporal Arg_comparator's to DATE, TIME, DATETIME data types.
The same idea is used in MySQL-5.6+.
This improves performance.
Problem:
When calculatung MIN() and MAX() in a query with GROUP BY, like this:
SELECT MIN(time_expr), MAX(time_expr) FROM t1 GROUP BY i;
the code in Item_sum_min_max::update_field() erroneosly used
string format comparison, therefore '100:20:30' was considered as
smaller than '10:20:30'.
Fix:
1. Implementing low level "native" related methods in class Time:
Time::Time(const Native &native) - convert native to Time
Time::to_native(Native *to, uint decimals) - convert Time to native
The "native" binary representation for TIME is equal to
the binary data format of Field_timef, which is used to
store TIME when mysql56_temporal_format is ON (default).
2. Implementing Type_handler_time_common "native" related methods:
Type_handler_time_common::cmp_native()
Type_handler_time_common::Item_val_native_with_conversion()
Type_handler_time_common::Item_val_native_with_conversion_result()
Type_handler_time_common::Item_param_val_native()
3. Implementing missing "native representation" related methods
in Field_time and Field_timef:
Field_time::store_native()
Field_time::val_native()
Field_timef::store_native()
Field_timef::val_native()
4. Implementing missing "native" related methods in all Items
that can have the TIME data type:
Item_timefunc::val_native()
Item_name_const::val_native()
Item_time_literal::val_native()
Item_cache_time::val_native()
Item_handled_func::val_native()
5. Marking Type_handler_time_common as "native ready".
So now Item_sum_min_max::update_field() calculates
values using min_max_update_native_field(),
which uses native binary representation rather than string representation.
Before this change, only the TIMESTAMP data type used native
representation to calculate MIN() and MAX().
Benchmarks (see more details in MDEV):
This change not only fixes the wrong result, but also
makes a "SELECT .. MAX.. GROUP BY .." query faster:
# TIME(0)
CREATE TABLE t1 (id INT, time_col TIME) ENGINE=HEAP;
INSERT INTO t1 VALUES (1,'10:10:10'); -- repeat this 1m times
SELECT id, MAX(time_col) FROM t1 GROUP BY id;
MySQL80: 0.159 sec
10.3: 0.108 sec
10.4: 0.094 sec (fixed)
# TIME(6):
CREATE TABLE t1 (id INT, time_col TIME(6)) ENGINE=HEAP;
INSERT INTO t1 VALUES (1,'10:10:10.999999'); -- repeat this 1m times
SELECT id, MAX(time_col) FROM t1 GROUP BY id;
My80: 0.154
10.3: 0.135
10.4: 0.093 (fixed)
An alternative implementation (replacing the one based on repertoire).
This implementation makes Field send itself to Protocol_text using
data type specific Protocol methods rather than field->val_str()
followed by protocol_text->store_str().
As now Field sends itself in the same way to all protocol types
(e.g. Protocol_binary, Protocol_text, Protocol_local),
the method Field::send_binary() was renamed just to Field::send().
Note, this change introduces symmetry between Field and Item,
because Items also send themself using a single method Item::send(),
which is used for *all* protocol types.
Performance improvement is achieved by the fact that Protocol_text
implements these data type specific methods using store_numeric_string_aux()
rather than store_string_aux(). The conversion now happens only when
character_set_results is not ASCII compatible character sets
(e.g. UCS2, UTF16, UTF32).
In the old code (before any MDEV-23162 work, e.g. as of 10.5.4),
Protocol_text::store(Field*) used val_str() for all data types.
So the execution went through the character set conversion routines
even for numeric and temporal data types.
Benchmarking summary (see details in MDEV-23478):
The new approach stably demonstrates additional improvement comparing
to the previous implementation (the smaller time - the better):
Original - the commit before MDEV-23162
be98036f25
1m9.336s
1m9.290s
1m9.300s
MDEV-23162 - the repertoire optimization
1m6.101s
1m5.988s
1m6.264s
MDEV-23478 - this commit
1m2.150s
1m2.079s
1m2.099s
Final added to:
- All reasonable classes inhereted from Field
- All classes inhereted from Protocol
- Almost all Handler classes
- Some important Item classes
The stripped size of mariadbd is just 4K smaller, but several object files
showed notable improvements in common execution paths.
- Checked field.o and item_sum.o
Other things:
- Added 'override' to a few class functions touched by this patch.
- Removed 'virtual' from a new class functions that had/got 'override'
- Changed Protocol_discard to inherit from Protocol instad of Protocol_text
Fix prefix key comparison in partitioning. Comparions must
take into account no more than prefix_len characters.
It used to compare prefix_len*mbmaxlen bytes.
- Some of the bug fixes are backports from 10.5!
- The fix in innobase/fil/fil0fil.cc is just a backport to get less
error messages in mysqld.1.err when running with valgrind.
- Renamed HAVE_valgrind_or_MSAN to HAVE_valgrind
When using field_conv(), which is called in case of field1=field2 copy in
fill_records(), full varstring's was copied, including unitialized bytes.
This caused valgrind to compilain about usage of unitialized bytes when
using Aria static length records.
Fixed by not using memcpy when copying varstrings but instead just copy
the real bytes.
CHECK constraint is checked by check_expression() which walks its
items and gets into Item_field::check_vcol_func_processor() to check
for conformity with foreign key list.
WITHOUT OVERLAPS is checked for same conformity in
mysql_prepare_create_table().
Long uniques are already impossible with InnoDB foreign keys. See
ER_CANT_CREATE_TABLE in test case.
2 accompanying bugs fixed (test main.constraints failed):
1. check->name.str lived on SP execute mem_root while "check" obj
itself lives on SP main mem_root. On second SP execute check->name.str
had garbage data. Fixed by allocating from thd->stmt_arena->mem_root
which is SP main mem_root.
2. CHECK_CONSTRAINT_IF_NOT_EXISTS value was mixed with
VCOL_FIELD_REF. VCOL_FIELD_REF is assigned in check_expression() and
then detected as CHECK_CONSTRAINT_IF_NOT_EXISTS in
handle_if_exists_options().
Existing cases for MDEV-16932 in main.constraints cover both fixes.
For DECIMAL[(M[,D])] datatype max_sort_length was not being honoured which was leading to buffer
overflow while making the sort key. The fix to this problem would be to create sort keys for decimals
with atmost max_sort_key bytes
Important:
The minimum value of max_sort_length has been raised to 8 (previously was 4),
so fixed size datatypes like DOUBLE and BIGINIT are not truncated for
lower values of max_sort_length.
For field with type INET, during EITS collection the min and max values are store in text
representation in the statistical table.
While retrieving the value from the statistical table, the value is stored back in the original
field using binary form instead of text and this was resulting in the crash.
Introduced 2 functions in the Field structure:
1) store_to_statistical_minmax_field
2) store_from_statistical_minmax_field
When neither MSAN nor Valgrind are enabled, declare
Field::mark_unused_memory_as_defined() as an empty inline function,
instead of declaring it as a virtual function.
MDEV-22073 MSAN use-of-uninitialized-value in
collect_statistics_for_table()
Other things:
innodb.analyze_table was changed to mainly test statistic
collection. Was discussed with Marko.
- Fixed mysql_prepare_create_table() constraint duplicate checking;
- Refactored period constraint handling in mysql_prepare_alter_table():
* No need to allocate new objects;
* Keep old constraint name but exclude it from dup checking by automatic_name;
- Some minor memory leaks fixed;
- Some conceptual TODOs.
Some .c and .cc files are compiled as part of Mariabackup.
Enabling -Wconversion for InnoDB would also enable it for
Mariabackup. The .h files are being included during
InnoDB or Mariabackup compilation.
Notably, GCC 5 (but not GCC 4 or 6 or later versions)
would report -Wconversion for x|=y when the type is
unsigned char. So, we will either write x=(uchar)(x|y)
or disable the -Wconversion warning for GCC 5.
bitmap_set_bit(), bitmap_flip_bit(), bitmap_clear_bit(), bitmap_is_set():
Always implement as inline functions.
This task deals with packing the sort key inside the sort buffer, which would
lead to efficient usage of the memory allocated for the sort buffer.
The changes brought by this feature are
1) Sort buffers would have sort keys of variable length
2) The format for sort keys inside the sort buffer would look like
|<sort_length><null_byte><key_part1><null_byte><key_part2>.......|
sort_length is the extra bytes that are required to store the variable
length of a sort key.
3) When packing of sort key is done we store the ORIGINAL VALUES inside
the sort buffer and not the STRXFRM form (mem-comparable sort keys).
4) Special comparison function packed_keys_comparison() is introduced
to compare 2 sort keys.
This patch also contains contributions from Sergei Petrunia.
compare_keys_but_name(): do not use KEY_PART_INFO::field for
Field::is_equal(). Following the logic of that code we need to
compare fields of a table. But KEY_PART_INFO::field sometimes
(when key part is shorter than table field) is a different field.
In that case Field::is_equal() returns incorrect result and
problems occur.
KEY_PART_INFO::field may become some strange field in
open_frm_error open_table_from_share(). I think this is an
incorrect logic, some tecnhical debt. I'm not fixing it right now,
because I don't have time. But I'm making Field::field_length
a const class member. Then, the only fishy code which changed that
field requires now a const_cast<>. I'm bringing attention to that
code with it. This change should not affect logic of the
program in any way.
This task deals with packing the non-sorted fields (or addon fields).
This would lead to efficient usage of the memory allocated for the sort buffer.
The changes brought by this feature are
1) Sort buffers would have records of variable length
2) Each record in the sort buffer would be stored like
<sort_key1><sort_key2>....<addon_length><null_bytes><field1><field2>....
addon_length is the extra bytes that are required to store the variable
length of addon field across different records.
3) Changes in rr_unpack_from_buffer and rr_from_tempfile to take into account
the variable length of records.
Ported WL#1509 Pack values of non-sorted fields in the sort buffer from
MySQL by Tor Didriksen
Old temporal data types (created with a pre-10.0 version of MariaDB)
are now displayed with a /* mariadb-5.3 */ comment in:
- SHOW CREATE TABLE
- DESCRIBE
- INFORMATION_SCHEMA.COLUMNS.COLUMN_TYPE
For example:
CREATE TABLE `t1` (
`t0` datetime /* mariadb-5.3 */ DEFAULT NULL,
`t6` datetime(6) /* mariadb-5.3 */ DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
Note, new temporal data types are displayed without a format comment.
- Making classes Field_time, Field_datetime, Field_timestamp abstract
- Adding instantiable Field_time0, Field_datetime0, Field_timestamp0 classes
- Removing redundant cast in field_conv.cc, item_timefunc.cc, sp.cc in calls for set_time() and get_timestamp()
- Replacing store_TIME() to store_timestamp() in log.cc and removing redundant cast
In order to:
- unify sql_yacc.yy and sql_yacc_ora.yy easier
- move more functionality from the parser to Type_handler
(so plugins can override the behavior)
this patch:
- removes rules sp_param_field_type_string and sp_param_field_type
from sql_yacc_ora.yy
- adds a new virtial method Type_handler::Column_definition_set_attributes()
