Commit 4e7121c0 authored by unknown's avatar unknown
Browse files

Bug#16712: group_concat returns odd srting insead of intended result 

  when calculating GROUP_CONCAT all blob fields are transformed
  to varchar when making the temp table.
  However a varchar has at max 2 bytes for length. 
  This fix makes the conversion only for blobs whose max length 
  is below that limit. 
  Otherwise blob field is created by make_string_field() call.


mysql-test/r/func_gconcat.result:
  Bug#16712: group_concat returns odd srting insead of intended result
    * testsuite for the bug
mysql-test/t/func_gconcat.test:
  Bug#16712: group_concat returns odd srting insead of intended result
    * testsuite for the bug
sql/item_sum.cc:
  Bug#16712: group_concat returns odd srting insead of intended result
    * force blob->varchar conversion for small enough blobs only
sql/sql_select.cc:
  Bug#16712: group_concat returns odd srting insead of intended result
    * force blob->varchar conversion for small enough blobs only
parent a8fd83d6

mysql-test/r/func_gconcat.result

+13 −0
Original line number Diff line number Diff line
@@ -641,3 +641,16 @@ select charset(group_concat(c1 order by c2)) from t1; 
charset(group_concat(c1 order by c2))

latin1

drop table t1;

CREATE TABLE t1 (a INT(10), b LONGTEXT, PRIMARY KEY (a));

SET GROUP_CONCAT_MAX_LEN = 20000000;

INSERT INTO t1 VALUES (1,REPEAT(CONCAT('A',CAST(CHAR(0) AS BINARY),'B'), 40000));

INSERT INTO t1 SELECT a + 1, b FROM t1;

SELECT a, CHAR_LENGTH(b) FROM t1;

a	CHAR_LENGTH(b)

1	120000

2	120000

SELECT CHAR_LENGTH( GROUP_CONCAT(b) ) FROM t1;

CHAR_LENGTH( GROUP_CONCAT(b) )

240001

SET GROUP_CONCAT_MAX_LEN = 1024;

DROP TABLE t1;

mysql-test/t/func_gconcat.test

+14 −0
Original line number Diff line number Diff line
@@ -433,3 +433,17 @@ create table t1 (c1 varchar(10), c2 int); 
select charset(group_concat(c1 order by c2)) from t1;

drop table t1;



#

# Bug #16712: group_concat returns odd string instead of intended result

#

CREATE TABLE t1 (a INT(10), b LONGTEXT, PRIMARY KEY (a));



SET GROUP_CONCAT_MAX_LEN = 20000000;



INSERT INTO t1 VALUES (1,REPEAT(CONCAT('A',CAST(CHAR(0) AS BINARY),'B'), 40000));

INSERT INTO t1 SELECT a + 1, b FROM t1;



SELECT a, CHAR_LENGTH(b) FROM t1;

SELECT CHAR_LENGTH( GROUP_CONCAT(b) ) FROM t1;

SET GROUP_CONCAT_MAX_LEN = 1024;

DROP TABLE t1;

sql/item_sum.cc

+7 −1
Original line number Diff line number Diff line
@@ -377,7 +377,13 @@ Field *Item_sum::create_tmp_field(bool group, TABLE *table, 
  case INT_RESULT:

    return new Field_longlong(max_length,maybe_null,name,table,unsigned_flag);

  case STRING_RESULT:

    if (max_length/collation.collation->mbmaxlen > 255 && convert_blob_length)

    /* 

      Make sure that the blob fits into a Field_varstring which has 

      2-byte lenght. 

    */

    if (max_length/collation.collation->mbmaxlen > 255 && 

        max_length/collation.collation->mbmaxlen < UINT_MAX16 &&

        convert_blob_length)

      return new Field_varstring(convert_blob_length, maybe_null,

                                 name, table,

                                 collation.collation);

sql/sql_select.cc

+12 −2
Original line number Diff line number Diff line
@@ -8011,7 +8011,12 @@ Field* create_tmp_field_from_field(THD *thd, Field* org_field, 
{

  Field *new_field;



  if (convert_blob_length && (org_field->flags & BLOB_FLAG))

  /* 

    Make sure that the blob fits into a Field_varstring which has 

    2-byte lenght. 

  */

  if (convert_blob_length && convert_blob_length < UINT_MAX16 &&

      (org_field->flags & BLOB_FLAG))

    new_field= new Field_varstring(convert_blob_length,

                                   org_field->maybe_null(),

                                   org_field->field_name, table,
@@ -8087,8 +8092,13 @@ static Field *create_tmp_field_from_item(THD *thd, Item *item, TABLE *table, 
    if ((type= item->field_type()) == MYSQL_TYPE_DATETIME ||

        type == MYSQL_TYPE_TIME || type == MYSQL_TYPE_DATE)

      new_field= item->tmp_table_field_from_field_type(table);

    /* 

      Make sure that the blob fits into a Field_varstring which has 

      2-byte lenght. 

    */

    else if (item->max_length/item->collation.collation->mbmaxlen > 255 &&

             convert_blob_length)

             item->max_length/item->collation.collation->mbmaxlen < UINT_MAX16

             && convert_blob_length)

      new_field= new Field_varstring(convert_blob_length, maybe_null,

                                     item->name, table,

                                     item->collation.collation);