From: Date: May 14 2007 3:43pm Subject: bk commit into 5.0 tree (mhansson:1.2443) BUG#23856 List-Archive: http://lists.mysql.com/commits/26616 X-Bug: 23856 Message-Id: <20070514134324.3C39C36052@linux-st28.site> Below is the list of changes that have just been committed into a local 5.0 repository of martin. When martin does a push these changes will be propagated to the main repository and, within 24 hours after the push, to the public repository. For information on how to access the public repository see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html ChangeSet@stripped, 2007-05-14 16:43:16+03:00, mhansson@stripped +5 -0 Bug #23856:GROUP_CONCAT and ORDER BY: junk from previous rows for query on I_S Problem: When group_concat() is given an ORDER BY or DISTINCT option, it uses a TREE structure to sort/remove duplicates. The current implementation incorrectly tries to store BLOB's inside the TREE structure for sorting, because at present BLOB Fields always keep a pointer to the actual data and not the data itself. In particular Item_func_group_concat::setup calls create_tmp_table with save_sum_fields == TRUE. According to a (removed) comment this should lead to blobs being stored inside the TREE, which is wrong. This flag's only effect wrt GROUP_BY is that the blob is stored using do_save_blob rather than do_conv_blob. There seems to be no difference between them. A to do comment is left above Field_copy::set for future work. ( version >= 5.1 ) Solution: Always use VARCHAR for the placeholder field. This leads to results being truncated when they exceed the maximum VARCHAR length (65535 bytes). In such cases we print a warning. See also Bug#28273: GROUP_CONCAT and ORDER BY: No warning when result gets truncated. mysql-test/r/func_gconcat.result@stripped, 2007-05-14 16:43:12+03:00, mhansson@stripped +32 -0 Bug #23856: correct result. mysql-test/t/func_gconcat.test@stripped, 2007-05-14 16:43:12+03:00, mhansson@stripped +24 -0 Bug #23856: test case. sql/field.h@stripped, 2007-05-14 16:43:13+03:00, mhansson@stripped +5 -0 Bug #23856: Introduced new constant field in Field_varstring for the maximum VARCHAR size. sql/item_sum.cc@stripped, 2007-05-14 16:43:13+03:00, mhansson@stripped +10 -4 Bug #23856: - changed UINT_MAX16 to Field_varstring::MAX_SIZE - The fix for the bug and motivation. - Removed comment containing the erroneous assumption that caused the bug. sql/sql_select.cc@stripped, 2007-05-14 16:43:13+03:00, mhansson@stripped +42 -41 Bug#23856: - Clarified and doxygenated comment regarding convert_blob_length (2 places) - Used Field_varstring::MAX_SIZE rather that UINT_MAX16. (2 places) # This is a BitKeeper patch. What follows are the unified diffs for the # set of deltas contained in the patch. The rest of the patch, the part # that BitKeeper cares about, is below these diffs. # User: mhansson # Host: linux-st28.site # Root: /home/martin/mysql/src/5.0o-bug23856 --- 1.200/sql/field.h 2007-04-02 11:50:16 +03:00 +++ 1.201/sql/field.h 2007-05-14 16:43:13 +03:00 @@ -1076,6 +1076,11 @@ public: class Field_varstring :public Field_longstr { public: + /* + The maximum space available in a Field_varstring, in bytes. See + length_bytes. + */ + static const int MAX_SIZE= UINT_MAX16; /* Store number of bytes used to store length (1 or 2) */ uint32 length_bytes; Field_varstring(char *ptr_arg, --- 1.205/sql/item_sum.cc 2007-04-02 11:50:17 +03:00 +++ 1.206/sql/item_sum.cc 2007-05-14 16:43:13 +03:00 @@ -420,7 +420,7 @@ Field *Item_sum::create_tmp_field(bool g 2-byte lenght. */ if (max_length/collation.collation->mbmaxlen > 255 && - convert_blob_length < UINT_MAX16 && convert_blob_length) + convert_blob_length < Field_varstring::MAX_SIZE && convert_blob_length) return new Field_varstring(convert_blob_length, maybe_null, name, table, collation.collation); @@ -3257,14 +3257,20 @@ bool Item_func_group_concat::setup(THD * tmp_table_param->force_copy_fields= force_copy_fields; DBUG_ASSERT(table == 0); /* + Currently we have to force conversion of BLOB values to VARCHAR's + if we are to store them in TREE objects used for ORDER BY and + DISTINCT. This leads to truncation if the BLOB's size exceeds + Field_varstring::MAX_SIZE. + */ + if (arg_count_order > 0 || distinct) + set_if_smaller(tmp_table_param->convert_blob_length, + Field_varstring::MAX_SIZE - 1); + /* We have to create a temporary table to get descriptions of fields (types, sizes and so on). Note that in the table, we first have the ORDER BY fields, then the field list. - - We need to set set_sum_field in true for storing value of blob in buffer - of a record instead of a pointer of one. */ if (!(table= create_tmp_table(thd, tmp_table_param, all_fields, (ORDER*) 0, 0, TRUE, --- 1.507/sql/sql_select.cc 2007-04-02 04:56:34 +03:00 +++ 1.508/sql/sql_select.cc 2007-05-14 16:43:13 +03:00 @@ -8699,23 +8699,22 @@ const_expression_in_where(COND *cond, It /* Create field for temporary table from given field - SYNOPSIS - create_tmp_field_from_field() - thd Thread handler - org_field field from which new field will be created - name New field name - table Temporary table - item !=NULL if item->result_field should point to new field. - This is relevant for how fill_record() is going to work: - If item != NULL then fill_record() will update - the record in the original table. - If item == NULL then fill_record() will update - the temporary table - convert_blob_length If >0 create a varstring(convert_blob_length) field - instead of blob. + @param thd Thread handler + @param org_field field from which new field will be created + @param name New field name + @param table Temporary table + @param item !=NULL if item->result_field should point to new field. + This is relevant for how fill_record() is going to + work: If item != NULL then fill_record() will update + the record in the original table. If item == NULL + then fill_record() will update the temporary table + @param convert_blob_length If inside the interval + (0, Field_varstring::MAX_SIZE) create a + varstring(convert_blob_length) field instead of + blob. - RETURN - 0 on error + @return + 0 on error new_created field */ @@ -8729,7 +8728,7 @@ Field* create_tmp_field_from_field(THD * Make sure that the blob fits into a Field_varstring which has 2-byte lenght. */ - if (convert_blob_length && convert_blob_length < UINT_MAX16 && + if (convert_blob_length && convert_blob_length < Field_varstring::MAX_SIZE && (org_field->flags & BLOB_FLAG)) new_field= new Field_varstring(convert_blob_length, org_field->maybe_null(), @@ -8820,7 +8819,8 @@ static Field *create_tmp_field_from_item 2-byte lenght. */ else if (item->max_length/item->collation.collation->mbmaxlen > 255 && - convert_blob_length < UINT_MAX16 && convert_blob_length) + convert_blob_length < Field_varstring::MAX_SIZE && + convert_blob_length) new_field= new Field_varstring(convert_blob_length, maybe_null, item->name, table, item->collation.collation); @@ -8879,31 +8879,32 @@ Field *create_tmp_field_for_schema(THD * /* Create field for temporary table - SYNOPSIS - create_tmp_field() - thd Thread handler - table Temporary table - item Item to create a field for - type Type of item (normally item->type) - copy_func If set and item is a function, store copy of item - in this array - from_field if field will be created using other field as example, + @param thd Thread handler + @param table Temporary table + @param item Item to create a field for + @param type Type of item (normally item->type) + @param copy_func If set and item is a function, store copy of item + in this array + + @param from_field if field will be created using other field as example, pointer example field will be written here - default_field If field has a default value field, store it here - group 1 if we are going to do a relative group by on result - modify_item 1 if item->result_field should point to new item. - This is relevent for how fill_record() is going to - work: - If modify_item is 1 then fill_record() will update - the record in the original table. - If modify_item is 0 then fill_record() will update - the temporary table - convert_blob_length If >0 create a varstring(convert_blob_length) field - instead of blob. - RETURN - 0 on error - new_created field + @param default_field If field has a default value field, store it here + @param group 1 if we are going to do a relative group by on result + @param modify_item 1 if item->result_field should point to new item. + This is relevent for how fill_record() is going to work: + If modify_item is 1 then fill_record() will update + the record in the original table. + If modify_item is 0 then fill_record() will update + the temporary table + + @param convert_blob_length If inside the interval (0, Field_varstring::MAX_SIZE) + create a varstring(convert_blob_length) field + instead of blob. + + @return + 0 on error + new_created field */ Field *create_tmp_field(THD *thd, TABLE *table,Item *item, Item::Type type, --- 1.68/mysql-test/r/func_gconcat.result 2007-03-29 19:20:02 +03:00 +++ 1.69/mysql-test/r/func_gconcat.result 2007-05-14 16:43:12 +03:00 @@ -737,4 +737,36 @@ SELECT GROUP_CONCAT(DISTINCT UCASE(b)) F GROUP_CONCAT(DISTINCT UCASE(b)) ONE.1,TWO.2,ONE.3 DROP TABLE t1; +SET group_concat_max_len= 65535; +CREATE TABLE t1( a TEXT, b INTEGER ); +INSERT INTO t1 VALUES ( 'a', 0 ), ( 'b', 1 ); +SELECT GROUP_CONCAT( a ORDER BY b ) FROM t1; +GROUP_CONCAT( a ORDER BY b ) +a,b +SELECT GROUP_CONCAT(DISTINCT a ORDER BY b) FROM t1; +GROUP_CONCAT(DISTINCT a ORDER BY b) +a,b +SELECT GROUP_CONCAT(DISTINCT a) FROM t1; +GROUP_CONCAT(DISTINCT a) +a,b +SET group_concat_max_len= 10; +SELECT GROUP_CONCAT(a ORDER BY b) FROM t1; +GROUP_CONCAT(a ORDER BY b) +a,b +SELECT GROUP_CONCAT(DISTINCT a ORDER BY b) FROM t1; +GROUP_CONCAT(DISTINCT a ORDER BY b) +a,b +SELECT GROUP_CONCAT(DISTINCT a) FROM t1; +GROUP_CONCAT(DISTINCT a) +a,b +SET group_concat_max_len= 65535; +CREATE TABLE t2( x TEXT ); +INSERT INTO t2 VALUES( REPEAT( 'a', 5000 ) ); +INSERT INTO t2 VALUES( REPEAT( 'b', 5000 ) ); +INSERT INTO t2 VALUES( REPEAT( 'a', 5000 ) ); +SELECT LENGTH( GROUP_CONCAT( DISTINCT x ) ) FROM t2; +LENGTH( GROUP_CONCAT( DISTINCT x ) ) +10001 +SET group_concat_max_len= DEFAULT; +DROP TABLE t1, t2; End of 5.0 tests --- 1.55/mysql-test/t/func_gconcat.test 2007-03-29 19:20:02 +03:00 +++ 1.56/mysql-test/t/func_gconcat.test 2007-05-14 16:43:12 +03:00 @@ -507,4 +507,28 @@ SELECT GROUP_CONCAT(DISTINCT UCASE(a)) F SELECT GROUP_CONCAT(DISTINCT UCASE(b)) FROM t1; DROP TABLE t1; +# +# Bug #23856:GROUP_CONCAT and ORDER BY: junk from previous rows for query on I_S +# +SET group_concat_max_len= 65535; +CREATE TABLE t1( a TEXT, b INTEGER ); +INSERT INTO t1 VALUES ( 'a', 0 ), ( 'b', 1 ); +SELECT GROUP_CONCAT( a ORDER BY b ) FROM t1; +SELECT GROUP_CONCAT(DISTINCT a ORDER BY b) FROM t1; +SELECT GROUP_CONCAT(DISTINCT a) FROM t1; +SET group_concat_max_len= 10; +SELECT GROUP_CONCAT(a ORDER BY b) FROM t1; +SELECT GROUP_CONCAT(DISTINCT a ORDER BY b) FROM t1; +SELECT GROUP_CONCAT(DISTINCT a) FROM t1; + +SET group_concat_max_len= 65535; +CREATE TABLE t2( x TEXT ); +INSERT INTO t2 VALUES( REPEAT( 'a', 5000 ) ); +INSERT INTO t2 VALUES( REPEAT( 'b', 5000 ) ); +INSERT INTO t2 VALUES( REPEAT( 'a', 5000 ) ); +SELECT LENGTH( GROUP_CONCAT( DISTINCT x ) ) FROM t2; + +SET group_concat_max_len= DEFAULT; +DROP TABLE t1, t2; + --echo End of 5.0 tests