WL#2474 "Multi Range Read: Change the default MRR implementation to implement new MRR interface"
WL#2475 "Batched range read functions for MyISAM/InnoDb"
"Index condition pushdown for MyISAM/InnoDB"
Igor's fix from sp1r-igor@olga.mysql.com-20080330055902-07614:
There could be observed the following problems:
1. EXPLAIN did not mention pushdown conditions from on expressions in the
'extra' column. As a result if a query had no where conditions pushed
down to a table, but had on conditions pushed to this table the 'extra'
column in the EXPLAIN for the table missed 'using where'.
2. Conditions for ref access were not eliminated from on expressions
though such conditions were eliminated from the where condition.
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.
