Problem:
Queries like this showed performance degratation in 10.4 over 10.3:
SELECT temporal_literal FROM t1;
SELECT temporal_literal + 1 FROM t1;
SELECT COUNT(*) FROM t1 WHERE temporal_column = temporal_literal;
SELECT COUNT(*) FROM t1 WHERE temporal_column = string_literal;
Fix:
Replacing the universal member "MYSQL_TIME cached_time" in
Item_temporal_literal to data type specific containers:
- Date in Item_date_literal
- Time in Item_time_literal
- Datetime in Item_datetime_literal
This restores the performance, and make it even better in some cases.
See benchmark results in MDEV.
Also, this change makes futher separations of Date, Time, Datetime
from each other, which will make it possible not to derive them from
a too heavy (40 bytes) MYSQL_TIME, and replace them to smaller data
type specific containers.
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)
- Adding optional qualifiers to data types:
CREATE TABLE t1 (a schema.DATE);
Qualifiers now work only for three pre-defined schemas:
mariadb_schema
oracle_schema
maxdb_schema
These schemas are virtual (hard-coded) for now, but may turn into real
databases on disk in the future.
- mariadb_schema.TYPE now always resolves to a true MariaDB data
type TYPE without sql_mode specific translations.
- oracle_schema.DATE translates to MariaDB DATETIME.
- maxdb_schema.TIMESTAMP translates to MariaDB DATETIME.
- Fixing SHOW CREATE TABLE to use a qualifier for a data type TYPE
if the current sql_mode translates TYPE to something else.
The above changes fix the reported problem, so this script:
SET sql_mode=ORACLE;
CREATE TABLE t2 AS SELECT mariadb_date_column FROM t1;
is now replicated as:
SET sql_mode=ORACLE;
CREATE TABLE t2 (mariadb_date_column mariadb_schema.DATE);
and the slave can unambiguously treat DATE as the true MariaDB DATE
without ORACLE specific translation to DATETIME.
Similar,
SET sql_mode=MAXDB;
CREATE TABLE t2 AS SELECT mariadb_timestamp_column FROM t1;
is now replicated as:
SET sql_mode=MAXDB;
CREATE TABLE t2 (mariadb_timestamp_column mariadb_schema.TIMESTAMP);
so the slave treats TIMESTAMP as the true MariaDB TIMESTAMP
without MAXDB specific translation to DATETIME.
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.
When processing a condition like:
WHERE timestamp_column='2010-00-01 00:00:00'
don't replace the constant to Item_datetime_literal if the constant
it has zeros (in the month or in the day).
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.
Respect system fields in NO_ZERO_DATE mode.
This is the subject for refactoring in MDEV-19597
Conflict resolution from 7d5223310789f967106d86ce193ef31b315ecff0
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.
Same array instance in two Item_func_in instances. First Item_func_in
instance is freed on table close. Second one is freed on
cleanup_after_query().
get_copy() depends on copy ctor for copying an item and hence does
shallow copy for default copy ctor. Use build_clone() for deep copy of
Item_func_in.
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.
The fix consists of three commits backported from 10.3:
1) Cleanup isnan() portability checks
(cherry picked from commit 7ffd7fe962)
2) Cleanup isinf() portability checks
Original problem reported by Wlad: re-compilation of 10.3 on top of 10.2
build would cache undefined HAVE_ISINF from 10.2, whereas it is expected
to be 1 in 10.3.
std::isinf() seem to be available on all supported platforms.
(cherry picked from commit bc469a0bdf)
3) Use std::isfinite in C++ code
This is addition to parent revision fixing build failures.
(cherry picked from commit 54999f4e75)
MDEV-20589: Server still crashes in Field::set_warning_truncated_wrong_value
- Use dbug_tmp_use_all_columns() to mark that all fields can be used
- Remove field->is_stat_field (not needed)
- Remove extra arguments to Field::clone() that should not be there
- Safety fix for Field::set_warning_truncated_wrong_value() to not crash
if table is zero in production builds (We have got crashes several times
here so better to be safe than sorry).
- Threat wrong character string warnings identical to other field
conversion warnings. This removes some warnings we before got from
internal conversion errors. There is no good reason why a user would
get an error in case of 'key_field='wrong-utf8-string' but not for
'field=wrong-utf8-string'. The old code could also easily give
thousands of no-sence warnings for one single statement.
The flag is_stat_field is not set for the min_value and max_value of field items
inside table share. This is a must requirement as we don't want to throw
warnings of truncation when we read values from the statistics table to the column
statistics of table share fields.
