Fix two problems in table elimination code:
- Before marking a "value" as bound, check if it is already bound. Marking the
same value as bound twice could confuse a module that depends on this value,
because Dep_module_XXX use counters to know when they become bound.
- When checking whether field is part of a key, ignore "extended keys" property.
- Make eliminate_tables_for_list() take into account that it is not possible
to eliminate a table if it is used in the upper-side ON expressions. Example:
xxx JOIN (t1 LEFT JOIN t2 ON cond ) ON func(t2.columns)
Here it would eliminate t2 which is not possible because of use of t2.columns.
of the 5.3 code line after a merge with 5.2 on 2010-10-28
in order not to allow the cost to access a joined table to be equal
to 0 ever.
Expanded data sets for many test cases to get the same execution plans
as before.
- Fix for MySQL BUG#52357 added NESTED_JOIN::is_fully_covered() which would
not take into account that MariaDB's table elimination could eliminate tables
from join plan (and so, from join nest).
Fixed the check in the function to compare post-table-elimination numbers.
Save no-records constant tables in JOIN::const_table_map before we invoke
eliminate_tables(). Failure to do so caused crash when the same table was
marked as constant two times
mysql-test/r/table_elim.result:
LPBUG#524025 Running RQG outer_join test leads to crash
- Testcase
mysql-test/t/table_elim.test:
LPBUG#524025 Running RQG outer_join test leads to crash
- Testcase
sql/sql_select.cc:
LPBUG#524025 Running RQG outer_join test leads to crash
Save no-records constant tables in JOIN::const_table_map before we invoke eliminate_tables(). Failure to do so caused crash when the same table was marked as constant two times.
- When analying multiple equalities, take into account that they
may not have a single table field that belongs to one of the tables
that we're trying to eliminate (and they are not useful for table
elimination in that case)
mysql-test/r/table_elim.result:
LPBUG#523593: Running RQG optimizer_no_subquery crashes MariaDB
- Testcase
mysql-test/t/table_elim.test:
LPBUG#523593: Running RQG optimizer_no_subquery crashes MariaDB
- Testcase
include/my_global.h:
MWL#17: Table elimination: fixes for windows
- Add ALIGN_MAX_UNIT (assume malloc returns data aligned to this much)
mysql-test/r/table_elim.result:
MWL#17: Table elimination: fixes for windows
- Use only lower-case as EXPLAIN [EXTENDED] changes case of table names
on windows
mysql-test/t/table_elim.test:
MWL#17: Table elimination: fixes for windows
- Use only lower-case as EXPLAIN [EXTENDED] changes case of table names
on windows
sql/opt_table_elimination.cc:
MWL#17: Table elimination: fixes for windows
- Add extra alignment-padding-space for stack-allocated buffers.
- Fix a trivial problem when OR-merging two multi-equalities
- Amend testsuite to provide full gcov coverage
mysql-test/r/table_elim.result:
MWL#17: Table elimination:
- Amend testsuite to provide full gcov coverage
mysql-test/t/table_elim.test:
MWL#17: Table elimination:
- Amend testsuite to provide full gcov coverage
- More testcases
- Set correct dependencies for non-bound multi-equalities.
mysql-test/r/table_elim.result:
MWL#17: Table elimination
- More testcases
mysql-test/t/table_elim.test:
MWL#17: Table elimination
- More testcases
sql/opt_table_elimination.cc:
MWL#17: Table elimination
- Set correct dependencies for non-bound multi-equalities.
- More testcases
- Let add_ft_key() set keyuse->usable
mysql-test/r/table_elim.result:
MWL#17: Table elimination
- More testcases
mysql-test/t/table_elim.test:
MWL#17: Table elimination
- More testcases
sql/sql_select.cc:
MWL#17: Table elimination
- Let add_ft_key() set keyuse->usable
- Make elimination work with aggregate functions. The problem was that aggregate functions
reported all table bits in used_tables(), and that prevented table elimination. Fixed by
making aggregate functions return more correct value from used_tables().
mysql-test/r/ps_11bugs.result:
MWL#17: Table elimination
- Update test results. The difference is because of Item_ref change: outer references to constants
are now recognized as constants, too.
mysql-test/r/subselect.result:
- Update test results. The difference is because of Item_ref change: outer references to constants
are now recognized as constants, too.
mysql-test/r/table_elim.result:
MWL#17: Table elimination
- Check that elimination works in presense of aggreagate functions
mysql-test/t/table_elim.test:
MWL#17: Table elimination
- Check that elimination works in presense of aggreagate functions
sql/item.h:
MWL#17: Table elimination
- Add Item_ref::const_item() which calls (*ref)->const_item(). Before this diff Item_ref used the
default implementation of const_item(){ return used_tables()==0; }. This is no longer true, as
COUNT(*) now has used_tables()==0 but const_item()==FALSE.
sql/item_sum.cc:
MWL#17: Table elimination
- Make Item_sum() and it descendants not to return all bits in used_tables(). This is needed
because otherwise table elimination can't work in presense of aggregate functions
- COUNT(*) now has used_tables()==0 and const_item()==FALSE. Had to change
Item_ref::const_item() to account for this.
sql/item_sum.h:
MWL#17: Table elimination
- Add comments
- First code. Elimination works for simple cases, passes the testsuite.
- Known issues:
= No elimination is done for aggregate functions.
= EXPLAIN EXTENDED shows eliminated tables (I think it better not)
= No benchmark yet
= The code needs some polishing.
mysql-test/r/table_elim.result:
MWL#17: Table elimination
- Testcases
mysql-test/t/table_elim.test:
MWL#17: Table elimination
- Testcases
sql/sql_select.cc:
MWL#17: Table elimination
sql/sql_select.h:
MWL#17: Table elimination
- Added JOIN_TAB::eliminated (is JOIN_TAB the best place to store this flag?)
sql/table.h:
MWL#17: Table elimination
- ADded NESTED_JOIN::n_tables. We need to have the number of real tables remaining in an outer join nest.
