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MWL#17: Table elimination

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mysql-test/r/table_elim.result:
  MWL#17: Table elimination
  - More tests
mysql-test/t/table_elim.test:
  MWL#17: Table elimination
  - More tests
sql/opt_table_elimination.cc:
  MWL#17: Table elimination
  - Code cleanup
sql/sql_select.cc:
  MWL#17: Table elimination
  - Code cleanup
sql/sql_select.h:
  MWL#17: Table elimination
  - Code cleanup
sql/table.h:
  MWL#17: Table elimination
  - Code cleanup
This commit is contained in:
Sergey Petrunya
2009-06-29 17:51:15 +04:00
parent d764108a2c
commit 9fa1bce436
6 changed files with 277 additions and 218 deletions
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20
sql/sql_select.h
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@ -57,14 +57,14 @@ typedef struct keyuse_t {
*/
bool *cond_guard;
/*
TRUE <=> This keyuse can be used to construct key access.
FALSE <=> Otherwise. Currently unusable KEYUSEs represent equalities
1 <=> This keyuse can be used to construct key access.
0 <=> Otherwise. Currently unusable KEYUSEs represent equalities
where one table column refers to another one, like this:
t.keyXpartA=func(t.keyXpartB)
This equality cannot be used for index access but is useful
for table elimination.
*/
bool usable;
int usable;
} KEYUSE;
class store_key;
@ -299,7 +299,12 @@ public:
fetching data from a cursor
*/
bool resume_nested_loop;
table_map const_table_map,found_const_table_map;
table_map const_table_map;
/*
Constant tables for which we have found a row (as opposed to those for
which we didn't).
*/
table_map found_const_table_map;
/* Tables removed by table elimination. Set to 0 before the elimination. */
table_map eliminated_tables;
@ -548,6 +553,10 @@ public:
return (unit == &thd->lex->unit && (unit->fake_select_lex == 0 ||
select_lex == unit->fake_select_lex));
}
inline table_map all_tables_map()
{
return (table_map(1) << tables) - 1;
}
private:
bool make_simple_join(JOIN *join, TABLE *tmp_table);
};
@ -755,6 +764,5 @@ inline bool optimizer_flag(THD *thd, uint flag)
return (thd->variables.optimizer_switch & flag);
}
void eliminate_tables(JOIN *join, uint *const_tbl_count,
table_map *const_tables);
void eliminate_tables(JOIN *join);