Commit 11d268ba authored by gkodinov/kgeorge@magare.gmz's avatar gkodinov/kgeorge@magare.gmz
Browse files

Merge gkodinov@bk-internal.mysql.com:/home/bk/mysql-5.0-opt 

into  magare.gmz:/home/kgeorge/mysql/autopush/B30355-5.0-opt
parents e854d43a 8c3d5135

include/mysql_com.h

+4 −0
Original line number Diff line number Diff line
@@ -393,6 +393,10 @@ typedef struct st_udf_init 
  char	  *ptr;				/* free pointer for function data */

  my_bool const_item;			/* 0 if result is independent of arguments */

} UDF_INIT;

/* 

  TODO: add a notion for determinism of the UDF. 

  See Item_udf_func::update_used_tables ()

*/



  /* Constants when using compression */

#define NET_HEADER_SIZE 4		/* standard header size */

mysql-test/r/udf.result

+27 −0
Original line number Diff line number Diff line
@@ -327,4 +327,31 @@ DROP FUNCTION check_const_len; 
DROP PROCEDURE check_const_len_sp;

DROP TRIGGER check_const_len_trigger;

DROP TABLE const_len_bug;

CREATE FUNCTION sequence RETURNS INTEGER SONAME "UDF_EXAMPLE_LIB";

CREATE TABLE t1 (a INT);

CREATE TABLE t2 (a INT PRIMARY KEY);

INSERT INTO t1 VALUES (4),(3),(2),(1);

INSERT INTO t2 SELECT * FROM t1;

SELECT sequence() AS seq, a FROM t1 ORDER BY seq ASC;

seq	a

1	4

2	3

3	2

4	1

SELECT sequence() AS seq, a FROM t1 ORDER BY seq DESC;

seq	a

4	1

3	2

2	3

1	4

SELECT * FROM t1 WHERE a = sequence();

a

SELECT * FROM t2 WHERE a = sequence();

a

1

2

3

4

DROP FUNCTION sequence;

DROP TABLE t1,t2;

End of 5.0 tests.

mysql-test/t/udf.test

+21 −0
Original line number Diff line number Diff line
@@ -362,4 +362,25 @@ DROP PROCEDURE check_const_len_sp; 
DROP TRIGGER check_const_len_trigger;

DROP TABLE const_len_bug;





#

# Bug #30355: Incorrect ordering of UDF results

#



--replace_result $UDF_EXAMPLE_LIB UDF_EXAMPLE_LIB

eval CREATE FUNCTION sequence RETURNS INTEGER SONAME "$UDF_EXAMPLE_LIB";

CREATE TABLE t1 (a INT);

CREATE TABLE t2 (a INT PRIMARY KEY);

INSERT INTO t1 VALUES (4),(3),(2),(1);

INSERT INTO t2 SELECT * FROM t1;



SELECT sequence() AS seq, a FROM t1 ORDER BY seq ASC;

SELECT sequence() AS seq, a FROM t1 ORDER BY seq DESC;



SELECT * FROM t1 WHERE a = sequence();

SELECT * FROM t2 WHERE a = sequence();



DROP FUNCTION sequence;

DROP TABLE t1,t2;



--echo End of 5.0 tests.

sql/item_func.cc

+6 −0
Original line number Diff line number Diff line
@@ -2968,6 +2968,12 @@ udf_handler::fix_fields(THD *thd, Item_result_field *func, 
    func->max_length=min(initid.max_length,MAX_BLOB_WIDTH);

    func->maybe_null=initid.maybe_null;

    const_item_cache=initid.const_item;

    /* 

      Keep used_tables_cache in sync with const_item_cache.

      See the comment in Item_udf_func::update_used tables.

    */  

    if (!const_item_cache && !used_tables_cache)

      used_tables_cache= RAND_TABLE_BIT;

    func->decimals=min(initid.decimals,NOT_FIXED_DEC);

  }

  initialized=1;

sql/item_func.h

+50 −0
Original line number Diff line number Diff line
@@ -1016,6 +1016,56 @@ class Item_udf_func :public Item_func 
    fixed= 1;

    return res;

  }

  void update_used_tables() 

  {

    /*

      TODO: Make a member in UDF_INIT and return if a UDF is deterministic or

      not.

      Currently UDF_INIT has a member (const_item) that is an in/out 

      parameter to the init() call.

      The code in udf_handler::fix_fields also duplicates the arguments 

      handling code in Item_func::fix_fields().

      

      The lack of information if a UDF is deterministic makes writing

      a correct update_used_tables() for UDFs impossible.

      One solution to this would be :

       - Add a is_deterministic member of UDF_INIT

       - (optionally) deprecate the const_item member of UDF_INIT

       - Take away the duplicate code from udf_handler::fix_fields() and

         make Item_udf_func call Item_func::fix_fields() to process its 

         arguments as for any other function.

       - Store the deterministic flag returned by <udf>_init into the 

       udf_handler. 

       - Don't implement Item_udf_func::fix_fields, implement

       Item_udf_func::fix_length_and_dec() instead (similar to non-UDF

       functions).

       - Override Item_func::update_used_tables to call 

       Item_func::update_used_tables() and add a RAND_TABLE_BIT to the 

       result of Item_func::update_used_tables() if the UDF is 

       non-deterministic.

       - (optionally) rename RAND_TABLE_BIT to NONDETERMINISTIC_BIT to

       better describe its usage.

       

      The above would require a change of the UDF API.

      Until that change is done here's how the current code works:

      We call Item_func::update_used_tables() only when we know that

      the function depends on real non-const tables and is deterministic.

      This can be done only because we know that the optimizer will

      call update_used_tables() only when there's possibly a new const

      table. So update_used_tables() can only make a Item_func more

      constant than it is currently.

      That's why we don't need to do anything if a function is guaranteed

      to return non-constant (it's non-deterministic) or is already a

      const.

    */  

    if ((used_tables_cache & ~PSEUDO_TABLE_BITS) && 

        !(used_tables_cache & RAND_TABLE_BIT))

    {

      Item_func::update_used_tables();

      if (!const_item_cache && !used_tables_cache)

        used_tables_cache= RAND_TABLE_BIT;

    }

  }

  void cleanup();

  Item_result result_type () const { return udf.result_type(); }

  table_map not_null_tables() const { return 0; }