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Merge mysql.com:/home/psergey/mysql-5.0-bug8804-r12

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into  mysql.com:/home/psergey/mysql-5.1-bug8804-r12-merge


sql/item_cmpfunc.cc:
  Auto merged
sql/item_cmpfunc.h:
  Auto merged
sql/item_subselect.h:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/mysqld.cc:
  Auto merged
sql/sql_lex.h:
  Auto merged
sql/sql_select.cc:
  Auto merged
sql/sql_select.h:
  Auto merged
mysql-test/r/ndb_subquery.result:
  Manual merge
mysql-test/r/subselect.result:
  Manual merge
mysql-test/r/subselect3.result:
  Manual merge
sql/item_subselect.cc:
  Manual merge
This commit is contained in:
unknown
2007-01-24 22:28:28 +03:00
parent 4ee9e407d4 130523af45
commit 713bb7a09e
14 changed files with 1309 additions and 273 deletions
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92
sql/item_subselect.h
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@@ -94,7 +94,7 @@ public:
return null_value;
}
bool fix_fields(THD *thd, Item **ref);
virtual bool exec(bool full_scan);
virtual bool exec();
virtual void fix_length_and_dec();
table_map used_tables() const;
table_map not_null_tables() const { return 0; }
@@ -104,6 +104,7 @@ public:
Item *get_tmp_table_item(THD *thd);
void update_used_tables();
void print(String *str);
virtual bool have_guarded_conds() { return FALSE; }
bool change_engine(subselect_engine *eng)
{
old_engine= engine;
@@ -250,13 +251,21 @@ protected:
bool transformed;
public:
/* Used to trigger on/off conditions that were pushed down to subselect */
bool enable_pushed_conds;
bool *pushed_cond_guards;
bool *get_cond_guard(int i)
{
return pushed_cond_guards ? pushed_cond_guards + i : NULL;
}
void set_cond_guard_var(int i, bool v) { pushed_cond_guards[i]= v; }
bool have_guarded_conds() { return test(pushed_cond_guards); }
Item_func_not_all *upper_item; // point on NOT/NOP before ALL/SOME subquery
Item_in_subselect(Item * left_expr, st_select_lex *select_lex);
Item_in_subselect()
:Item_exists_subselect(), optimizer(0), abort_on_null(0), transformed(0),
enable_pushed_conds(TRUE), upper_item(0)
pushed_cond_guards(NULL), upper_item(0)
{}
subs_type substype() { return IN_SUBS; }
@@ -341,23 +350,22 @@ public:
SYNOPSIS
exec()
full_scan TRUE - Pushed-down predicates are disabled, the engine
must disable made based on those predicates.
FALSE - Pushed-down predicates are in effect.
DESCRIPTION
Execute the engine. The result of execution is subquery value that is
either captured by previously set up select_result-based 'sink' or
stored somewhere by the exec() method itself.
A required side effect: if full_scan==TRUE, subselect_engine->no_rows()
should return correct result.
A required side effect: If at least one pushed-down predicate is
disabled, subselect_engine->no_rows() must return correct result after
the exec() call.
RETURN
0 - OK
1 - Either an execution error, or the engine was be "changed", and
1 - Either an execution error, or the engine was "changed", and the
caller should call exec() again for the new engine.
*/
virtual int exec(bool full_scan)= 0;
virtual int exec()= 0;
virtual uint cols()= 0; /* return number of columns in select */
virtual uint8 uncacheable()= 0; /* query is uncacheable */
enum Item_result type() { return res_type; }
@@ -392,7 +400,7 @@ public:
void cleanup();
int prepare();
void fix_length_and_dec(Item_cache** row);
int exec(bool full_scan);
int exec();
uint cols();
uint8 uncacheable();
void exclude();
@@ -416,7 +424,7 @@ public:
void cleanup();
int prepare();
void fix_length_and_dec(Item_cache** row);
int exec(bool full_scan);
int exec();
uint cols();
uint8 uncacheable();
void exclude();
@@ -430,11 +438,30 @@ public:
struct st_join_table;
/*
A subquery execution engine that evaluates the subquery by doing one index
lookup in a unique index.
This engine is used to resolve subqueries in forms
outer_expr IN (SELECT tbl.unique_key FROM tbl WHERE subq_where)
or, tuple-based:
(oe1, .. oeN) IN (SELECT uniq_key_part1, ... uniq_key_partK
FROM tbl WHERE subqwhere)
i.e. the subquery is a single table SELECT without GROUP BY, aggregate
functions, etc.
*/
class subselect_uniquesubquery_engine: public subselect_engine
{
protected:
st_join_table *tab;
Item *cond;
Item *cond; /* The WHERE condition of subselect */
/*
TRUE<=> last execution produced empty set. Valid only when left
expression is NULL.
@@ -454,7 +481,7 @@ public:
void cleanup();
int prepare();
void fix_length_and_dec(Item_cache** row);
int exec(bool full_scan);
int exec();
uint cols() { return 1; }
uint8 uncacheable() { return UNCACHEABLE_DEPENDENT; }
void exclude();
@@ -472,16 +499,47 @@ class subselect_indexsubquery_engine: public subselect_uniquesubquery_engine
{
/* FALSE for 'ref', TRUE for 'ref-or-null'. */
bool check_null;
/*
The "having" clause. This clause (further reffered to as "artificial
having") was inserted by subquery transformation code. It contains
Item(s) that have a side-effect: they record whether the subquery has
produced a row with NULL certain components. We need to use it for cases
like
(oe1, oe2) IN (SELECT t.key, t.no_key FROM t1)
where we do index lookup on t.key=oe1 but need also to check if there
was a row such that t.no_key IS NULL.
NOTE: This is currently here and not in the uniquesubquery_engine. Ideally
it should have been in uniquesubquery_engine in order to allow execution of
subqueries like
(oe1, oe2) IN (SELECT primary_key, non_key_maybe_null_field FROM tbl)
We could use uniquesubquery_engine for the first component and let
Item_is_not_null_test( non_key_maybe_null_field) to handle the second.
However, subqueries like the above are currently not handled by index
lookup-based subquery engines, the engine applicability check misses
them: it doesn't switch the engine for case of artificial having and
[eq_]ref access (only for artifical having + ref_or_null or no having).
The above example subquery is handled as a full-blown SELECT with eq_ref
access to one table.
Due to this limitation, the "artificial having" currently needs to be
checked by only in indexsubquery_engine.
*/
Item *having;
public:
// constructor can assign THD because it will be called after JOIN::prepare
subselect_indexsubquery_engine(THD *thd, st_join_table *tab_arg,
Item_subselect *subs, Item *where,
bool chk_null)
Item *having_arg, bool chk_null)
:subselect_uniquesubquery_engine(thd, tab_arg, subs, where),
check_null(chk_null)
check_null(chk_null),
having(having_arg)
{}
int exec(bool full_scan);
int exec();
void print (String *str);
};