Bug#11750518 41090: ORDER BY TRUNCATES GROUP_CONCAT RESULT

When temporary tables is used for result sorting
result field for gconcat function is created using
group_concat_max_len size. It leads to result truncation
when character_set_results is multi-byte character set due
to insufficient tmp table field size.
The fix is to increase temporary table field size for
gconcat. Method make_string_field() is overloaded
for Item_func_group_concat class and uses
max_characters * collation.collation->mbmaxlen size for
result field. max_characters is maximum number of characters
what can fit into max_length size.


mysql-test/r/ctype_utf16.result:
  test result
mysql-test/r/ctype_utf32.result:
  test result
mysql-test/r/ctype_utf8.result:
  test result
mysql-test/t/ctype_utf16.test:
  test case
mysql-test/t/ctype_utf32.test:
  test case
mysql-test/t/ctype_utf8.test:
  test case
sql/item.h:
  make Item::make_string_field() virtual
sql/item_sum.cc:
  added Item_func_group_concat::make_string_field(TABLE *table) method
  which uses max_characters * collation.collation->mbmaxlen size for
  result item. max_characters is maximum number of characters what can
  fit into max_length size.
sql/item_sum.h:
  added Item_func_group_concat::make_string_field(TABLE *table) method

6 files changed, 82 insertions, 1 deletions

diff --git a/mysql-test/r/ctype_utf16.result b/mysql-test/r/ctype_utf16.result
index dfffd8142de..42897ca580f 100644
--- a/mysql-test/r/ctype_utf16.result
+++ b/mysql-test/r/ctype_utf16.result
@@ -1126,5 +1126,19 @@ NULL
 Warnings:
 Warning	1301	Result of repeat() was larger than max_allowed_packet (1048576) - truncated
 #
+# Bug#11750518 41090: ORDER BY TRUNCATES GROUP_CONCAT RESULT
+#
+SET NAMES utf8, @@character_set_connection=utf16;
+SELECT id, CHAR_LENGTH(GROUP_CONCAT(body)) AS l
+FROM (SELECT 'a' AS id, REPEAT('foo bar', 100) AS body
+UNION ALL
+SELECT 'a' AS id, REPEAT('bla bla', 100) AS body) t1
+GROUP BY id
+ORDER BY l DESC;
+id	l
+a	512
+Warnings:
+Warning	1260	Row 1 was cut by GROUP_CONCAT()
+#
 # End of 5.5 tests
 #
diff --git a/mysql-test/r/ctype_utf32.result b/mysql-test/r/ctype_utf32.result
index d749383d249..2433f2426a4 100644
--- a/mysql-test/r/ctype_utf32.result
+++ b/mysql-test/r/ctype_utf32.result
@@ -1167,5 +1167,19 @@ CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END
 b
 DROP TABLE t1;
 #
+# Bug#11750518 41090: ORDER BY TRUNCATES GROUP_CONCAT RESULT
+#
+SET NAMES utf8, @@character_set_connection=utf32;
+SELECT id, CHAR_LENGTH(GROUP_CONCAT(body)) AS l
+FROM (SELECT 'a' AS id, REPEAT('foo bar', 100) AS body
+UNION ALL
+SELECT 'a' AS id, REPEAT('bla bla', 100) AS body) t1
+GROUP BY id
+ORDER BY l DESC;
+id	l
+a	256
+Warnings:
+Warning	1260	Row 1 was cut by GROUP_CONCAT()
+#
 # End of 5.5 tests
 #
diff --git a/mysql-test/r/ctype_utf8.result b/mysql-test/r/ctype_utf8.result
index cfbf6cee3a2..8237f174514 100644
--- a/mysql-test/r/ctype_utf8.result
+++ b/mysql-test/r/ctype_utf8.result
@@ -2788,7 +2788,7 @@ create table t1 as select group_concat(1,2,3) as c1;
 show create table t1;
 Table	Create Table
 t1	CREATE TABLE `t1` (
-  `c1` varchar(342) CHARACTER SET utf8 DEFAULT NULL
+  `c1` text CHARACTER SET utf8
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
 create table t1 as select 1 as c1 union select 'a';
@@ -5010,5 +5010,19 @@ id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 Warnings:
 Note	1003	select 'abcdÁÂÃÄÅ' AS `abcdÁÂÃÄÅ`,_latin1'abcd\xC3\x81\xC3\x82\xC3\x83\xC3\x84\xC3\x85' AS `abcdÁÂÃÄÅ`,_utf8'abcd\xC3\x81\xC3\x82\xC3\x83\xC3\x84\xC3\x85' AS `abcdÁÂÃÄÅ`
 #
+# Bug#11750518 41090: ORDER BY TRUNCATES GROUP_CONCAT RESULT
+#
+SET NAMES utf8;
+SELECT id, CHAR_LENGTH(GROUP_CONCAT(body)) AS l
+FROM (SELECT 'a' AS id, REPEAT('foo bar', 100) AS body
+UNION ALL
+SELECT 'a' AS id, REPEAT('bla bla', 100) AS body) t1
+GROUP BY id
+ORDER BY l DESC;
+id	l
+a	1024
+Warnings:
+Warning	1260	Row 2 was cut by GROUP_CONCAT()
+#
 # End of 5.5 tests
 #
diff --git a/mysql-test/t/ctype_utf16.test b/mysql-test/t/ctype_utf16.test
index 4ac47a4ac53..ca6802d96dc 100644
--- a/mysql-test/t/ctype_utf16.test
+++ b/mysql-test/t/ctype_utf16.test
@@ -762,6 +762,20 @@ DROP TABLE t1;
 
 SELECT space(date_add(101, INTERVAL CHAR('1' USING utf16) hour_second)); 
 
+
+--echo #
+--echo # Bug#11750518 41090: ORDER BY TRUNCATES GROUP_CONCAT RESULT
+--echo #
+
+SET NAMES utf8, @@character_set_connection=utf16;
+SELECT id, CHAR_LENGTH(GROUP_CONCAT(body)) AS l
+FROM (SELECT 'a' AS id, REPEAT('foo bar', 100) AS body
+UNION ALL
+SELECT 'a' AS id, REPEAT('bla bla', 100) AS body) t1
+GROUP BY id
+ORDER BY l DESC;
+
+
 #
 ## TODO: add tests for all engines
 #
diff --git a/mysql-test/t/ctype_utf32.test b/mysql-test/t/ctype_utf32.test
index 10d365572bf..c36e623541a 100644
--- a/mysql-test/t/ctype_utf32.test
+++ b/mysql-test/t/ctype_utf32.test
@@ -841,5 +841,18 @@ SELECT CASE s1 WHEN 'a' THEN 'b' ELSE 'c' END FROM t1;
 DROP TABLE t1;
 
 --echo #
+--echo # Bug#11750518 41090: ORDER BY TRUNCATES GROUP_CONCAT RESULT
+--echo #
+
+SET NAMES utf8, @@character_set_connection=utf32;
+SELECT id, CHAR_LENGTH(GROUP_CONCAT(body)) AS l
+FROM (SELECT 'a' AS id, REPEAT('foo bar', 100) AS body
+UNION ALL
+SELECT 'a' AS id, REPEAT('bla bla', 100) AS body) t1
+GROUP BY id
+ORDER BY l DESC;
+
+
+--echo #
 --echo # End of 5.5 tests
 --echo #
diff --git a/mysql-test/t/ctype_utf8.test b/mysql-test/t/ctype_utf8.test
index a519a417192..8254f99249f 100644
--- a/mysql-test/t/ctype_utf8.test
+++ b/mysql-test/t/ctype_utf8.test
@@ -1562,5 +1562,17 @@ SET NAMES utf8;
 EXPLAIN EXTENDED SELECT 'abcdÁÂÃÄÅ', _latin1'abcdÁÂÃÄÅ', _utf8'abcdÁÂÃÄÅ';
 
 --echo #
+--echo # Bug#11750518 41090: ORDER BY TRUNCATES GROUP_CONCAT RESULT
+--echo #
+
+SET NAMES utf8;
+SELECT id, CHAR_LENGTH(GROUP_CONCAT(body)) AS l
+FROM (SELECT 'a' AS id, REPEAT('foo bar', 100) AS body
+UNION ALL
+SELECT 'a' AS id, REPEAT('bla bla', 100) AS body) t1
+GROUP BY id
+ORDER BY l DESC;
+
+--echo #
 --echo # End of 5.5 tests
 --echo #