- When window functions are present, JOIN::simple_order should be set
to FALSE. (Otherwise, the optimizer may attempt to do a "pre-sorting"
on the first join_tab. Which can work in some cases, but generally
isn't)
- filesort tries to only read table fields that it requires. Window
function requires its temp.table field. In order to pass this info
to filesort, added an implementation of Item_window_func::
register_field_in_read_map.
" The sort order for the sub-sequence of window functions starting
from the element marked by SORTORDER_CHANGE_FLAG up to the next
element marked by SORTORDER_CHANGE_FLAG must be taken from the
last element of the sub-sequence (not from the first one)."
- Moving the new my_charlen()-based code handling multi-byte characters
from READ_INFO::field_field() to a new method READ_INFO::read_mbtail()
- Reusing read_mbtail() in READ_INFO::read_value(), instead of the old
my_mbcharlen()-based code which did not catch broken byte sequences
- Rename Window_funcs_computation to Window_funcs_computation_step
- Introduce Window_func_sort which invokes filesort and then
invokes computation of all window functions that use this ordering.
- Expose Window functions' sort operations in EXPLAIN|ANALYZE FORMAT=JSON
that the call-back comparison function returns a positive
number when arg1 < arg2, and a negative number when arg1 > arg2.
This is not in line with other implementation of sorting
algorithm.
Changed bubble_sort: now a negative result from the comparison
function means that arg1 < arg2, and positive result means
that arg1 > arg2.
Changed accordingly all call-back functions that are used as
parameters in the call of bubble_sort.
Added a test case to check the proper sorting of window functions.
- Removing the "diff_if_only_endspace_difference" argument from
MY_COLLATION_HANDLER::strnncollsp(), my_strnncollsp_simple(),
as well as in the function template MY_FUNCTION_NAME(strnncollsp)
in strcoll.ic
- Removing the "diff_if_only_space_different" from ha_compare_text(),
hp_rec_key_cmp().
- Adding a new function my_strnncollsp_padspace_bin() and reusing
it instead of duplicate code pieces in my_strnncollsp_8bit_bin(),
my_strnncollsp_latin1_de(), my_strnncollsp_tis620(),
my_strnncollsp_utf8_cs().
- Adding more tests for better coverage of the trailing space handling.
- Removing the unused definition of HA_END_SPACE_ARE_EQUAL
- Hook window function computation into the right location.
- Add a testcase which shows that HAVING is now checked before
the window function computation step.
Item_func_or_sum.
Implemented method update_used_tables for class Item_findow_func.
Added the flag Item::with_window_func.
Made sure that window functions could be used only in SELECT list
and ORDER BY clause.
Added test cases that checked different illegal placements of
window functions.
1. Fixing Field_time::get_equal_const_item() to pass TIME_FUZZY_DATES
and TIME_INVALID_DATES to get_time_with_conversion().
This is needed to make the recursively called Item::get_date() return
non-NULL values on garbage input. This makes Field_time::get_equal_const_item()
work consistently with how Item::val_time_packed() works.
2. Fixing Item::get_date() to return TIME'00:00:00' rather than
DATE'0000-00-00' on empty or garbage input when:
- TIME_FUZZY_DATES is enabled
- The caller requested a TIME value (by passing TIME_TIME_ONLY).
This is needed to avoid conversion of DATE'0000-00-00' to TIME
in get_time_with_conversion(), which would erroneously try to subtract
CURRENT_DATE from DATE'0000-00-00' and return TIME'-838:59:59' rather than
the desired zero value TIME'00:00:00'.
#1 and #2 fix these type of scripts to return one row with both
MyISAM and InnoDB, with and without an index on t1.b:
CREATE TABLE t1 (a ENUM('a'), b TIME, c INT, KEY(b));
INSERT INTO t1 VALUES ('','00:00:00',0);
SELECT * FROM t1 WHERE b='';
SELECT * FROM t1 WHERE a=b;
SELECT * FROM t1 IGNORE INDEX(b) WHERE b='';
SELECT * FROM t1 IGNORE INDEX(b) WHERE a=b;
Additionally, #1 and #2 fix the originally reported in MDEV-9604 crash
in Item::save_in_field(), because now execution goes through a different
path, so save_in_field() is called for a Item_time_literal instance
(which is non-NULL) rather than a Item_cache_str instance (which could
return NULL without setting null_value).
3. Fixing Field_temporal::get_equal_const_item_datetime() to enable
equal field propagation for DATETIME and TIMESTAMP in case of
comparison (e.g. when ANY_SUBST), for symmetry with
Field_newdate::get_equal_const_item(). This fixes a number of problems
with empty set returned on comparison to empty/garbage input.
Now all SELECT queries in this script return one row for MyISAM and InnoDB,
with and without an index on t1.b:
CREATE TABLE t1 (a ENUM('a'), b DATETIME, c INT, KEY(b));
INSERT INTO t1 VALUES ('','0000-00-00 00:00:00',0);
SELECT * FROM t1 WHERE b='';
SELECT * FROM t1 WHERE a=b;
SELECT * FROM t1 IGNORE INDEX(b) WHERE b='';
SELECT * FROM t1 IGNORE INDEX(b) WHERE a=b;
Added 5 minute timeout before automaticlally removing threads from thread
cache.
This solves a problem with jemalloc, which is slow with a small
thread cache and also makes thread_cache big enough that most users
doesn't have to touch it
LOG-SLOW-SLAVE-STATEMENTS NOT DISPLAYED.
These parameters were moved from the command line options to
the system variables section. Treatment of the
opt_log_slow_slave_statements changed to let the
dynamic change of the variable.
with window functions. Added the test case for it.
Also allowed to use aliases for set functions in partition and order lists
that are specified in window functions.
