- 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.
We can call setup_partition_border_check() from
JOIN::make_aggr_tables_info(), provided that call is made after
appropriate set_items_ref_array() call.
Added class Window_funcs_computation, with setup() method to setup
execution, and exec() to run window function computation.
setup() is currently trivial. In the future, it is expected to optimize
the number of sorting operations and passes that are done over the temp.
table.
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.
filesort and init_read_record() for the same table.
This will simplify code for WINDOW FUNCTIONS (MDEV-6115)
- Filesort_info renamed to SORT_INFO and moved to filesort.h
- filesort now returns SORT_INFO
- init_read_record() now takes a SORT_INFO parameter.
- unique declaration is moved to uniques.h
- subselect caching of buffers is now more explicit than before
- filesort_buffer is now reusable even if rec_length has changed.
- filsort_free_buffers() and free_io_cache() calls are removed
- Remove one malloc() when using get_addon_fields()
Other things:
- Added --debug-assert-on-not-freed-memory option to make it easier to
debug some not-freed-memory issues.
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.
- "Early NULLs filtering" optimization used to "peel off" Item_ref and
Item_direct_ref wrappers from an outside column reference before
adding "outer_table_col IS NOT NULL" into JOIN::outer_ref_cond.
- When this happened in a subquery that was evaluated in a post-GROUP-BY
context, attempt to evaluate JOIN::outer_ref_cond would fetch an
incorrect value of outer_table_col.
of mdev-8789.
Fixed a bug in TABLE_LIST::print.
Fixed another bug for the case when the definition of a
WITH table contained column list while the join in the main
query used two instances of this table.
"Re-factor the code for post-join operations".
The patch mainly contains the code ported from mysql-5.6 and
created for two essential architectural changes:
1. WL#5558: Resolve ORDER BY execution method at the optimization stage
2. WL#6071: Inline tmp tables into the nested loops algorithm
The first task was implemented for mysql-5.6 by Ole John Aske.
It allows to make all decisions on ORDER BY operation at the optimization
stage.
The second task implemented for mysql-5.6 by Evgeny Potemkin adds JOIN_TAB
nodes for post-join operations that require temporary tables. It allows
to execute these operations within the nested loops algorithm that used to
be used before this task only for join queries. Besides these task moves
all planning on the execution of these operations from the execution phase
to the optimization phase.
Some other re-factoring changes of mysql-5.6 were pulled in, mainly because
it was easier to pull them in than roll them back. In particular all
changes concerning Ref_ptr_array were incorporated.
The port required some changes in the MariaDB code that concerned the
functionality of EXPLAIN and ANALYZE. This was done mainly by Sergey
Petrunia.
The select mentioned in the bug attempted to create a temporary table
using the maria storage engine. The table needs to have primary keys such that
duplicates can be removed. Unfortunately this use case has a longer
than allowed key and the tmp table got created without a temporary key.
We must not allow materialization for the subquery if the total key
length and key parts is greater than what the storage engine supports.
When one evaluates row-based comparison like (X, Y) = (A,B), one should
first call bring_value() for the Item that returns row value. If you
don't do that and just attempt to read values of X and Y, you get stale
values.
Semi-join/Materialization can take a row-based comparison apart and
make ref access from it. In that case, we need to call bring_value()
to get the index lookup components.
Creating a CONNECT object on client connect and pass this to the working thread which creates the THD.
Split LOCK_thread_count to different mutexes
Added LOCK_thread_start to syncronize threads
Moved most usage of LOCK_thread_count to dedicated functions
Use next_thread_id() instead of thread_id++
Other things:
- Thread id now starts from 1 instead of 2
- Added cast for thread_id as thread id is now of type my_thread_id
- Made THD->host const (To ensure it's not changed)
- Removed some DBUG_PRINT() about entering/exiting mutex as these was already logged by mutex code
- Fixed that aborted_connects and connection_errors_internal are counted in all cases
- Don't take locks for current_linfo when we set it (not needed as it was 0 before)
