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cleanup: simplify multi-update's juggling with positions

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introduce Item_temptable_rowid() that is used to store
table->file->position() in the temporary table record
This commit is contained in:
Sergei Golubchik
2018-04-10 11:33:47 +02:00
parent c368878fac
commit e17e798599
5 changed files with 65 additions and 49 deletions
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20
sql/item_strfunc.cc
View File

@ -5204,3 +5204,23 @@ null:
my_free(names);
return NULL;
}
Item_temptable_rowid::Item_temptable_rowid(TABLE *table_arg)
: Item_str_func(table_arg->in_use), table(table_arg)
{
max_length= table->file->ref_length;
}
void Item_temptable_rowid::fix_length_and_dec()
{
used_tables_cache= table->map;
const_item_cache= false;
}
String *Item_temptable_rowid::val_str(String *str)
{
if (!((null_value= table->null_row)))
table->file->position(table->record[0]);
str_value.set((char*)(table->file->ref), max_length, &my_charset_bin);
return &str_value;
}

21
sql/item_strfunc.h
View File

@ -1751,5 +1751,24 @@ public:
{ return get_item_copy<Item_func_dyncol_list>(thd, this); }
};
#endif /* ITEM_STRFUNC_INCLUDED */
/*
this is used by JOIN_TAB::keep_current_rowid
and stores handler::position().
It has nothing to do with _rowid pseudo-column, that the parser supports.
*/
class Item_temptable_rowid :public Item_str_func
{
public:
TABLE *table;
Item_temptable_rowid(TABLE *table_arg);
const Type_handler *type_handler() const { return &type_handler_string; }
Field *create_tmp_field(bool group, TABLE *table)
{ return create_table_field_from_handler(table); }
String *val_str(String *str);
const char *func_name() const { return "<rowid>"; }
void fix_length_and_dec();
Item *get_copy(THD *thd)
{ return get_item_copy<Item_temptable_rowid>(thd, this); }
};
#endif /* ITEM_STRFUNC_INCLUDED */

18
sql/sql_select.cc
View File

@ -23400,13 +23400,10 @@ get_sort_by_table(ORDER *a,ORDER *b, List<TABLE_LIST> &tables,
calc how big buffer we need for comparing group entries.
*/
static void
calc_group_buffer(JOIN *join,ORDER *group)
void calc_group_buffer(TMP_TABLE_PARAM *param, ORDER *group)
{
uint key_length=0, parts=0, null_parts=0;
if (group)
join->group= 1;
for (; group ; group=group->next)
{
Item *group_item= *group->item;
@ -23476,9 +23473,16 @@ calc_group_buffer(JOIN *join,ORDER *group)
if (group_item->maybe_null)
null_parts++;
}
join->tmp_table_param.group_length=key_length+null_parts;
join->tmp_table_param.group_parts=parts;
join->tmp_table_param.group_null_parts=null_parts;
param->group_length= key_length + null_parts;
param->group_parts= parts;
param->group_null_parts= null_parts;
}
static void calc_group_buffer(JOIN *join, ORDER *group)
{
if (group)
join->group= 1;
calc_group_buffer(&join->tmp_table_param, group);
}

1
sql/sql_select.h
View File

@ -2382,6 +2382,7 @@ int append_possible_keys(MEM_ROOT *alloc, String_list &list, TABLE *table,
#define RATIO_TO_PACK_ROWS 2
#define MIN_STRING_LENGTH_TO_PACK_ROWS 10
void calc_group_buffer(TMP_TABLE_PARAM *param, ORDER *group);
TABLE *create_tmp_table(THD *thd,TMP_TABLE_PARAM *param,List<Item> &fields,
ORDER *group, bool distinct, bool save_sum_fields,
ulonglong select_options, ha_rows rows_limit,

54
sql/sql_update.cc
View File

@ -2167,22 +2167,12 @@ loop_end:
tbl->prepare_for_position();
join->map2table[tbl->tablenr]->keep_current_rowid= true;
Field_string *field= new Field_string(tbl->file->ref_length, 0,
&field_name,
&my_charset_bin);
if (!field)
DBUG_RETURN(1);
field->init(tbl);
/*
The field will be converted to varstring when creating tmp table if
table to be updated was created by mysql 4.1. Deny this.
*/
field->can_alter_field_type= 0;
Item_field *ifield= new (thd->mem_root) Item_field(join->thd, (Field *) field);
if (!ifield)
Item_temptable_rowid *item=
new (thd->mem_root) Item_temptable_rowid(tbl);
if (!item)
DBUG_RETURN(1);
ifield->maybe_null= 0;
if (temp_fields.push_back(ifield, thd->mem_root))
item->fix_fields(thd, 0);
if (temp_fields.push_back(item, thd->mem_root))
DBUG_RETURN(1);
} while ((tbl= tbl_it++));
@ -2193,10 +2183,10 @@ loop_end:
group.direction= ORDER::ORDER_ASC;
group.item= (Item**) temp_fields.head_ref();
tmp_param->quick_group=1;
tmp_param->field_count=temp_fields.elements;
tmp_param->group_parts=1;
tmp_param->group_length= table->file->ref_length;
tmp_param->quick_group= 1;
tmp_param->field_count= temp_fields.elements;
tmp_param->func_count= temp_fields.elements - 1;
calc_group_buffer(tmp_param, &group);
/* small table, ignore SQL_BIG_TABLES */
my_bool save_big_tables= thd->variables.big_tables;
thd->variables.big_tables= FALSE;
@ -2384,29 +2374,11 @@ int multi_update::send_data(List<Item> &not_used_values)
{
int error;
TABLE *tmp_table= tmp_tables[offset];
/*
For updatable VIEW store rowid of the updated table and
rowids of tables used in the CHECK OPTION condition.
*/
uint field_num= 0;
List_iterator_fast<TABLE> tbl_it(unupdated_check_opt_tables);
/* Set first tbl = table and then tbl to tables from tbl_it */
TABLE *tbl= table;
do
{
tbl->file->position(tbl->record[0]);
memcpy((char*) tmp_table->field[field_num]->ptr,
(char*) tbl->file->ref, tbl->file->ref_length);
/*
For outer joins a rowid field may have no NOT_NULL_FLAG,
so we have to reset NULL bit for this field.
(set_notnull() resets NULL bit only if available).
*/
tmp_table->field[field_num]->set_notnull();
field_num++;
} while ((tbl= tbl_it++));
if (copy_funcs(tmp_table_param[offset].items_to_copy, thd))
DBUG_RETURN(1);
/* Store regular updated fields in the row. */
DBUG_ASSERT(1 + unupdated_check_opt_tables.elements ==
tmp_table_param[offset].func_count);
fill_record(thd, tmp_table,
tmp_table->field + 1 + unupdated_check_opt_tables.elements,
*values_for_table[offset], TRUE, FALSE);