Commit d31e997d authored by unknown's avatar unknown
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A fix and a test case for Bug#12736 "Server crash during a select". 

The bug was in JOIN::join_free which was wrongly determining that
all joins have been already executed and therefore all used tables
can be closed.


mysql-test/r/subselect_innodb.result:
  - test results fixed (Bug#12736 "Server crash during a select
mysql-test/t/subselect_innodb.test:
  - a test case for Bug#12736 "Server crash during a select": test
  that ha_index_or_rnd_end and mysql_unlock_tables are called
  for all used tables in proper order.
sql/item_subselect.cc:
  - implement subselect_union_engine::is_executed
sql/item_subselect.h:
  - implement Item_subselect::is_evaluated. This function is used
  to check whether we can clean up a non-correlated join of a subquery
  when cleaning up the join of the outer query
sql/sql_lex.h:
  - declare st_select_lex::cleanup_all_joins
sql/sql_select.cc:
  - remove an argument from JOIN::join_free, it's now not used
  - reimplement JOIN::join_free to not unlock tables if there
    is a subquery that has not yet been evaluated. Make sure that the
    new implementation calls ha_index_or_rnd_end for every table in
    the join and inner joins, because all table cursors must be closed
    before mysql_unlock_tables.
sql/sql_select.h:
  - JOIN::join_free signature changed
sql/sql_union.cc:
  - implement a helper method st_select_lex::cleanup_all_joins, which
    recursively walks over a tree of joins and calls cleanup() for
    each join.
parent 20a6f152

mysql-test/r/subselect_innodb.result

+20 −0
Original line number Diff line number Diff line
@@ -152,3 +152,23 @@ EXECUTE my_stmt; 
b	count(*)

deallocate prepare my_stmt;

drop table t1,t2;

CREATE TABLE t1 (

school_name varchar(45) NOT NULL,

country varchar(45) NOT NULL,    

funds_requested float NOT NULL,

schooltype varchar(45) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=utf8;

insert into t1 values ("the school", "USA", 1200, "Human");

select count(country) as countrycount, sum(funds_requested) as smcnt,

country, (select sum(funds_requested) from t1) as total_funds

from t1

group by country;

countrycount	smcnt	country	total_funds

1	1200	USA	1200

select count(country) as countrycount, sum(funds_requested) as smcnt,

country, (select sum(funds_requested) from t1) as total_funds

from t1

group by country;

countrycount	smcnt	country	total_funds

1	1200	USA	1200

drop table t1;

mysql-test/t/subselect_innodb.test

+22 −0
Original line number Diff line number Diff line
@@ -161,3 +161,25 @@ deallocate prepare my_stmt; 
drop table t1,t2;



# End of 4.1 tests



CREATE TABLE t1 (

  school_name varchar(45) NOT NULL,

  country varchar(45) NOT NULL,    

  funds_requested float NOT NULL,

  schooltype varchar(45) NOT NULL

) ENGINE=InnoDB DEFAULT CHARSET=utf8;



insert into t1 values ("the school", "USA", 1200, "Human");



select count(country) as countrycount, sum(funds_requested) as smcnt,

       country, (select sum(funds_requested) from t1) as total_funds

from t1

group by country;



select count(country) as countrycount, sum(funds_requested) as smcnt,

       country, (select sum(funds_requested) from t1) as total_funds

from t1

group by country;



drop table t1;

sql/item_subselect.cc

+6 −0
Original line number Diff line number Diff line
@@ -1413,6 +1413,12 @@ void subselect_union_engine::cleanup() 
}





bool subselect_union_engine::is_executed() const

{

  return unit->executed;

}





void subselect_uniquesubquery_engine::cleanup()

{

  DBUG_ENTER("subselect_uniquesubquery_engine::cleanup");

sql/item_subselect.h

+16 −0
Original line number Diff line number Diff line
@@ -109,6 +109,12 @@ class Item_subselect :public Item_result_field 
    engine_changed= 1;

    return eng == 0;

  }

  /*

    True if this subquery has been already evaluated. Implemented only for

    single select and union subqueries only.

  */

  bool is_evaluated() const;



  /*

    Used by max/min subquery to initialize value presence registration

    mechanism. Engine call this method before rexecution query.
@@ -317,6 +323,7 @@ class subselect_engine: public Sql_alloc 
  virtual void print(String *str)= 0;

  virtual bool change_result(Item_subselect *si, select_subselect *result)= 0;

  virtual bool no_tables()= 0;

  virtual bool is_executed() const { return FALSE; }

};
@@ -342,6 +349,7 @@ class subselect_single_select_engine: public subselect_engine 
  void print (String *str);

  bool change_result(Item_subselect *si, select_subselect *result);

  bool no_tables();

  bool is_executed() const { return executed; }

};
@@ -363,6 +371,7 @@ class subselect_union_engine: public subselect_engine 
  void print (String *str);

  bool change_result(Item_subselect *si, select_subselect *result);

  bool no_tables();

  bool is_executed() const;

};
@@ -411,3 +420,10 @@ class subselect_indexsubquery_engine: public subselect_uniquesubquery_engine 
  int exec();

  void print (String *str);

};





inline bool Item_subselect::is_evaluated() const

{

  return engine->is_executed();

}

sql/sql_lex.h

+6 −1
Original line number Diff line number Diff line
@@ -386,12 +386,12 @@ class st_select_lex_unit: public st_select_lex_node { 
  select_result *result;

  ulong found_rows_for_union;

  bool res;

public:

  bool  prepared, // prepare phase already performed for UNION (unit)

    optimized, // optimize phase already performed for UNION (unit)

    executed, // already executed

    cleaned;



public:

  // list of fields which points to temporary table for union

  List<Item> item_list;

  /*
@@ -638,6 +638,11 @@ class st_select_lex: public st_select_lex_node 
    SELECT_LEX and all nested SELECT_LEXes and SELECT_LEX_UNITs).

  */

  bool cleanup();

  /*

    Recursively cleanup the join of this select lex and of all nested

    select lexes.

  */

  void cleanup_all_joins(bool full);

};

typedef class st_select_lex SELECT_LEX;