Commit 50c8c206 authored by unknown's avatar unknown
Browse files

Fixed bug#13575: SP funcs in select with distinct/group and order by can 

produce wrong data

By default Item_sp_func::val_str() returns string from it's result_field 
internal buffer. When grouping is present Item_copy_string is used to 
store SP function result, but it doesn't additionally buffer the result.
When the next record is read, internal buffer is overwritten, due to
this Item_copy_string::val_str() will have wrong data. Thus producing
weird query result.

The Item_func_sp::val_str() now makes a copy of returned value to prevent
occasional corruption.


mysql-test/t/sp.test:
  Added test case for bug#13575: SP funcs in select with distinct/group and order by can
  produce wrong data
mysql-test/r/sp.result:
  Added test case for bug#13575: SP funcs in select with distinct/group and
      order by can produce wrong data
sql/item_func.h:
  Fixed bug#13575: SP funcs in select with distinct/group and order by can
      produce wrong data
      The Item_func_sp::val_str() now makes a copy of returned value to prevent
      occasinal corruption.
parent 58bf749f

mysql-test/r/sp.result

+16 −0
Original line number Diff line number Diff line
@@ -4786,4 +4786,20 @@ i 
0

drop table t3|

drop procedure bug16887|

create table t3 (f1 int, f2 varchar(3), primary key(f1)) engine=innodb|

insert into t3 values (1,'aaa'),(2,'bbb'),(3,'ccc')|

CREATE FUNCTION bug13575 ( p1 integer ) 

returns varchar(3) 

BEGIN 

DECLARE v1 VARCHAR(10) DEFAULT null;

SELECT f2 INTO v1 FROM t3 WHERE f1 = p1; 

RETURN v1;

END|

select distinct f1, bug13575(f1) from t3 order by f1|

f1	bug13575(f1)

1	aaa

2	bbb

3	ccc

drop function bug13575;

drop table t3|

drop table t1,t2;

mysql-test/t/sp.test

+16 −0
Original line number Diff line number Diff line
@@ -5630,6 +5630,22 @@ call bug16887()| 
drop table t3|

drop procedure bug16887|



#

# Bug#13575 SP funcs in select with distinct/group and order by can

#           produce bad data

#

create table t3 (f1 int, f2 varchar(3), primary key(f1)) engine=innodb|

insert into t3 values (1,'aaa'),(2,'bbb'),(3,'ccc')|

CREATE FUNCTION bug13575 ( p1 integer ) 

returns varchar(3) 

BEGIN 

DECLARE v1 VARCHAR(10) DEFAULT null;

SELECT f2 INTO v1 FROM t3 WHERE f1 = p1; 

RETURN v1;

END|

select distinct f1, bug13575(f1) from t3 order by f1|

drop function bug13575;

drop table t3|



#

# BUG#NNNN: New bug synopsis

sql/item_func.h

+13 −1
Original line number Diff line number Diff line
@@ -1421,9 +1421,21 @@ class Item_func_sp :public Item_func 


  String *val_str(String *str)

  {

    String buf;

    char buff[20];

    buf.set(buff, 20, str->charset());

    buf.length(0);

    if (execute(&result_field))

      return NULL;

    return result_field->val_str(str);

    /*

      result_field will set buf pointing to internal buffer

      of the resul_field. Due to this it will change any time

      when SP is executed. In order to prevent occasional

      corruption of returned value, we make here a copy.

    */

    result_field->val_str(&buf);

    str->copy(buf);

    return str;

  }



  virtual bool change_context_processor(byte *cntx)