MySQL数据库

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sql_select.cpp：源码内容

if (item->maybe_null)
{
Field *field=item->get_tmp_table_field();
field->ptr[-1]= (byte) (field->is_null() ? 1 : 0);
}
}
}
#endif
if (!join->having || join->having->val_int())
{
join->found_records++;
if ((error=table->file->write_row(table->record[0])))
{
if (error == HA_ERR_FOUND_DUPP_KEY ||
error == HA_ERR_FOUND_DUPP_UNIQUE)
goto end;
if (create_myisam_from_heap(join->thd, table, &join->tmp_table_param,
error,1))
DBUG_RETURN(-1); // Not a table_is_full error
table->uniques=0; // To ensure rows are the same
}
if (++join->send_records >= join->tmp_table_param.end_write_records &&
join->do_send_rows)
{
if (!(join->select_options & OPTION_FOUND_ROWS))
DBUG_RETURN(-3);
join->do_send_rows=0;
join->unit->select_limit_cnt = HA_POS_ERROR;
DBUG_RETURN(0);
}
}
}
end:
DBUG_RETURN(0);
}
/* Group by searching after group record and updating it if possible */
/* ARGSUSED */
static int
end_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
TABLE *table=join->tmp_table;
ORDER *group;
int error;
DBUG_ENTER("end_update");
if (end_of_records)
DBUG_RETURN(0);
if (join->thd->killed) // Aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-2); /* purecov: inspected */
}
join->found_records++;
copy_fields(&join->tmp_table_param); // Groups are copied twice.
/* Make a key of group index */
for (group=table->group ; group ; group=group->next)
{
Item *item= *group->item;
item->save_org_in_field(group->field);
#ifdef EMBEDDED_LIBRARY
join->thd->net.last_errno= 0;
#endif
/* Store in the used key if the field was 0 */
if (item->maybe_null)
group->buff[-1]=item->null_value ? 1 : 0;
}
if (!table->file->index_read(table->record[1],
join->tmp_table_param.group_buff,0,
HA_READ_KEY_EXACT))
{ /* Update old record */
restore_record(table,record[1]);
update_tmptable_sum_func(join->sum_funcs,table);
if ((error=table->file->update_row(table->record[1],
table->record[0])))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
DBUG_RETURN(0);
}
/* The null bits are already set */
KEY_PART_INFO *key_part;
for (group=table->group,key_part=table->key_info[0].key_part;
group ;
group=group->next,key_part++)
memcpy(table->record[0]+key_part->offset, group->buff, key_part->length);
init_tmptable_sum_functions(join->sum_funcs);
copy_funcs(join->tmp_table_param.items_to_copy);
if ((error=table->file->write_row(table->record[0])))
{
if (create_myisam_from_heap(join->thd, table, &join->tmp_table_param,
error, 0))
DBUG_RETURN(-1); // Not a table_is_full error
/* Change method to update rows */
table->file->ha_index_init(0);
join->join_tab[join->tables-1].next_select=end_unique_update;
}
join->send_records++;
DBUG_RETURN(0);
}
/* Like end_update, but this is done with unique constraints instead of keys */
static int
end_unique_update(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
TABLE *table=join->tmp_table;
int error;
DBUG_ENTER("end_unique_update");
if (end_of_records)
DBUG_RETURN(0);
if (join->thd->killed) // Aborted by user
{
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-2); /* purecov: inspected */
}
init_tmptable_sum_functions(join->sum_funcs);
copy_fields(&join->tmp_table_param); // Groups are copied twice.
copy_funcs(join->tmp_table_param.items_to_copy);
if (!(error=table->file->write_row(table->record[0])))
join->send_records++; // New group
else
{
if ((int) table->file->get_dup_key(error) < 0)
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
if (table->file->rnd_pos(table->record[1],table->file->dupp_ref))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
restore_record(table,record[1]);
update_tmptable_sum_func(join->sum_funcs,table);
if ((error=table->file->update_row(table->record[1],
table->record[0])))
{
table->file->print_error(error,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-1); /* purecov: inspected */
}
}
DBUG_RETURN(0);
}
/* ARGSUSED */
static int
end_write_group(JOIN *join, JOIN_TAB *join_tab __attribute__((unused)),
bool end_of_records)
{
TABLE *table=join->tmp_table;
int error;
int idx= -1;
DBUG_ENTER("end_write_group");
if (join->thd->killed)
{ // Aborted by user
my_error(ER_SERVER_SHUTDOWN,MYF(0)); /* purecov: inspected */
DBUG_RETURN(-2); /* purecov: inspected */
}
if (!join->first_record || end_of_records ||
(idx=test_if_group_changed(join->group_fields)) >= 0)
{
if (join->first_record || (end_of_records && !join->group))
{
if (join->procedure)
join->procedure->end_group();
int send_group_parts= join->send_group_parts;
if (idx < send_group_parts)
{
if (!join->first_record)
{
/* No matching rows for group function */
join->clear();
}
copy_sum_funcs(join->sum_funcs,
join->sum_funcs_end[send_group_parts]);
if (join->having && join->having->val_int() == 0)
error= -1;
else if ((error=table->file->write_row(table->record[0])))
{
if (create_myisam_from_heap(join->thd, table,
&join->tmp_table_param,
error, 0))
DBUG_RETURN(-1);
/*
If table->file->write_row() was failed because of 'out of memory'
and tmp table succesfully created, reset error.
*/
error=0;
}
if (join->rollup.state != ROLLUP::STATE_NONE && error <= 0)
{
if (join->rollup_write_data((uint) (idx+1), table))
error= 1;
}
if (error > 0)
DBUG_RETURN(-1);
if (end_of_records)
DBUG_RETURN(0);
}
}
else
{
if (end_of_records)
DBUG_RETURN(0);
join->first_record=1;
VOID(test_if_group_changed(join->group_fields));
}
if (idx < (int) join->send_group_parts)
{
copy_fields(&join->tmp_table_param);
copy_funcs(join->tmp_table_param.items_to_copy);
if (init_sum_functions(join->sum_funcs, join->sum_funcs_end[idx+1]))
DBUG_RETURN(-1);
if (join->procedure)
join->procedure->add();
DBUG_RETURN(0);
}
}
if (update_sum_func(join->sum_funcs))
DBUG_RETURN(-1);
if (join->procedure)
join->procedure->add();
DBUG_RETURN(0);
}
/*****************************************************************************
Remove calculation with tables that aren't yet read. Remove also tests
against fields that are read through key where the table is not a
outer join table.
We can't remove tests that are made against columns which are stored
in sorted order.
*****************************************************************************/
/* Return 1 if right_item is used removable reference key on left_item */
static bool test_if_ref(Item_field *left_item,Item *right_item)
{
Field *field=left_item->field;
// No need to change const test. We also have to keep tests on LEFT JOIN
if (!field->table->const_table && !field->table->maybe_null)
{
Item *ref_item=part_of_refkey(field->table,field);
if (ref_item && ref_item->eq(right_item,1))
{
if (right_item->type() == Item::FIELD_ITEM)
return (field->eq_def(((Item_field *) right_item)->field));
if (right_item->const_item() && !(right_item->is_null()))
{
/*
We can remove binary fields and numerical fields except float,
as float comparison isn't 100 % secure
We have to keep binary strings to be able to check for end spaces
*/
if (field->binary() &&
field->real_type() != FIELD_TYPE_STRING &&
field->real_type() != FIELD_TYPE_VAR_STRING &&
(field->type() != FIELD_TYPE_FLOAT || field->decimals() == 0))
{
return !store_val_in_field(field,right_item);
}
}
}
}
return 0; // keep test
}
static COND *
make_cond_for_table(COND *cond, table_map tables, table_map used_table)
{
if (used_table && !(cond->used_tables() & used_table))
return (COND*) 0; // Already checked
if (cond->type() == Item::COND_ITEM)
{
if (((Item_cond*) cond)->functype() == Item_func::COND_AND_FUNC)
{
/* Create new top level AND item */
Item_cond_and *new_cond=new Item_cond_and;
if (!new_cond)
return (COND*) 0; // OOM /* purecov: inspected */
List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
while ((item=li++))
{
Item *fix=make_cond_for_table(item,tables,used_table);
if (fix)
new_cond->argument_list()->push_back(fix);
}
switch (new_cond->argument_list()->elements) {
case 0:
return (COND*) 0; // Always true
case 1:
return new_cond->argument_list()->head();
default:
/*
Item_cond_and do not need fix_fields for execution, its parameters
are fixed or do not need fix_fields, too
*/
new_cond->quick_fix_field();
new_cond->used_tables_cache=
((Item_cond_and*) cond)->used_tables_cache &
tables;
return new_cond;
}
}
else
{ // Or list
Item_cond_or *new_cond=new Item_cond_or;
if (!new_cond)
return (COND*) 0; // OOM /* purecov: inspected */
List_iterator<Item> li(*((Item_cond*) cond)->argument_list());
Item *item;
while ((item=li++))
{
Item *fix=make_cond_for_table(item,tables,0L);
if (!fix)
return (COND*) 0; // Always true
new_cond->argument_list()->push_back(fix);
}
/*
Item_cond_and do not need fix_fields for execution, its parameters
are fixed or do not need fix_fields, too
*/
new_cond->quick_fix_field();
new_cond->used_tables_cache= ((Item_cond_or*) cond)->used_tables_cache;
new_cond->top_level_item();
return new_cond;
}
}
/*
Because the following test takes a while and it can be done
table_count times, we mark each item that we have examined with the result
of the test
*/
if (cond->marker == 3 || (cond->used_tables() & ~tables))
return (COND*) 0; // Can't check this yet
if (cond->marker == 2 || cond->eq_cmp_result() == Item::COND_OK)
return cond; // Not boolean op
if (((Item_func*) cond)->functype() == Item_func::EQ_FUNC)
{
Item *left_item= ((Item_func*) cond)->arguments()[0];
Item *right_item= ((Item_func*) cond)->arguments()[1];
if (left_item->type() == Item::FIELD_ITEM &&
test_if_ref((Item_field*) left_item,right_item))
{
cond->marker=3; // Checked when read
return (COND*) 0;
}
if (right_item->type() == Item::FIELD_ITEM &&
test_if_ref((Item_field*) right_item,left_item))
{
cond->marker=3; // Checked when read
return (COND*) 0;
}
}
cond->marker=2;
return cond;
}
static Item *
part_of_refkey(TABLE *table,Field *field)
{
if (!table->reginfo.join_tab)
return (Item*) 0; // field from outer non-select (UPDATE,...)
uint ref_parts=table->reginfo.join_tab->ref.key_parts;
if (ref_parts)
{
KEY_PART_INFO *key_part=
table->key_info[table->reginfo.join_tab->ref.key].key_part;
for (uint part=0 ; part < ref_parts ; part++,key_part++)
if (field->eq(key_part->field) &&
!(key_part->key_part_flag & HA_PART_KEY_SEG))
return table->reginfo.join_tab->ref.items[part];
}
return (Item*) 0;
}
/*****************************************************************************
Test if one can use the key to resolve ORDER BY
SYNOPSIS
test_if_order_by_key()
order Sort order
table Table to sort
idx Index to check
used_key_parts Return value for used key parts.
NOTES
used_key_parts is set to correct key parts used if return value != 0
(On other cases, used_key_part may be changed)
RETURN
1 key is ok.
0 Key can't be used
-1 Reverse key can be used
*****************************************************************************/
static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx,
uint *used_key_parts)
{
KEY_PART_INFO *key_part,*key_part_end;
key_part=table->key_info[idx].key_part;
key_part_end=key_part+table->key_info[idx].key_parts;
key_part_map const_key_parts=table->const_key_parts[idx];
int reverse=0;
DBUG_ENTER("test_if_order_by_key");
for (; order ; order=order->next, const_key_parts>>=1)
{
Field *field=((Item_field*) (*order->item))->field;
int flag;
/*
Skip key parts that are constants in the WHERE clause.
These are already skipped in the ORDER BY by const_expression_in_where()
*/
for (; const_key_parts & 1 ; const_key_parts>>= 1)
key_part++;
if (key_part == key_part_end || key_part->field != field)
DBUG_RETURN(0);
/* set flag to 1 if we can use read-next on key, else to -1 */
flag= ((order->asc == !(key_part->key_part_flag & HA_REVERSE_SORT)) ?
1 : -1);
if (reverse && flag != reverse)
DBUG_RETURN(0);
reverse=flag; // Remember if reverse
key_part++;
}
*used_key_parts= (uint) (key_part - table->key_info[idx].key_part);
if (reverse == -1 && !(table->file->index_flags(idx, *used_key_parts-1, 1) &
HA_READ_PREV))
reverse= 0; // Index can't be used
DBUG_RETURN(reverse);
}
static uint find_shortest_key(TABLE *table, const key_map *usable_keys)
{
uint min_length= (uint) ~0;
uint best= MAX_KEY;
if (!usable_keys->is_clear_all())
{
for (uint nr=0; nr < table->keys ; nr++)
{
if (usable_keys->is_set(nr))
{
if (table->key_info[nr].key_length < min_length)
{
min_length=table->key_info[nr].key_length;
best=nr;
}
}
}
}
return best;
}
/*
Test if a second key is the subkey of the first one.
SYNOPSIS
is_subkey()
key_part First key parts
ref_key_part Second key parts
ref_key_part_end Last+1 part of the second key
NOTE
Second key MUST be shorter than the first one.
RETURN
1 is a subkey
0 no sub key
*/
inline bool
is_subkey(KEY_PART_INFO *key_part, KEY_PART_INFO *ref_key_part,
KEY_PART_INFO *ref_key_part_end)
{
for (; ref_key_part < ref_key_part_end; key_part++, ref_key_part++)
if (!key_part->field->eq(ref_key_part->field))
return 0;
return 1;
}
/*
Test if we can use one of the 'usable_keys' instead of 'ref' key for sorting
SYNOPSIS
test_if_subkey()
ref Number of key, used for WHERE clause
usable_keys Keys for testing
RETURN
MAX_KEY If we can't use other key
the number of found key Otherwise
*/
static uint
test_if_subkey(ORDER *order, TABLE *table, uint ref, uint ref_key_parts,
const key_map *usable_keys)
{
uint nr;
uint min_length= (uint) ~0;
uint best= MAX_KEY;
uint not_used;
KEY_PART_INFO *ref_key_part= table->key_info[ref].key_part;
KEY_PART_INFO *ref_key_part_end= ref_key_part + ref_key_parts;
for (nr= 0 ; nr < table->keys ; nr++)
{
if (usable_keys->is_set(nr) &&
table->key_info[nr].key_length < min_length &&
table->key_info[nr].key_parts >= ref_key_parts &&
is_subkey(table->key_info[nr].key_part, ref_key_part,
ref_key_part_end) &&
test_if_order_by_key(order, table, nr, &not_used))
{
min_length= table->key_info[nr].key_length;
best= nr;
}
}
return best;
}
/*
Test if we can skip the ORDER BY by using an index.
If we can use an index, the JOIN_TAB / tab->select struct
is changed to use the index.
Return:
0 We have to use filesort to do the sorting
1 We can use an index.
*/
static bool
test_if_skip_sort_order(JOIN_TAB *tab,ORDER *order,ha_rows select_limit,
bool no_changes)
{
int ref_key;
uint ref_key_parts;
TABLE *table=tab->table;
SQL_SELECT *select=tab->select;
key_map usable_keys;
DBUG_ENTER("test_if_skip_sort_order");
LINT_INIT(ref_key_parts);
/*
Check which keys can be used to resolve ORDER BY.
We must not try to use disabled keys.
*/
usable_keys= table->keys_in_use;
for (ORDER *tmp_order=order; tmp_order ; tmp_order=tmp_order->next)
{
if ((*tmp_order->item)->type() != Item::FIELD_ITEM)
{
usable_keys.clear_all();
DBUG_RETURN(0);
}
usable_keys.intersect(((Item_field*) (*tmp_order->item))->
field->part_of_sortkey);
if (usable_keys.is_clear_all())
DBUG_RETURN(0); // No usable keys
}
ref_key= -1;
/* Test if constant range in WHERE */
if (tab->ref.key >= 0 && tab->ref.key_parts)
{
ref_key= tab->ref.key;
ref_key_parts= tab->ref.key_parts;
if (tab->type == JT_REF_OR_NULL || tab->type == JT_FT)
DBUG_RETURN(0);
}
else if (select && select->quick) // Range found by opt_range
{
ref_key= select->quick->index;
ref_key_parts= select->quick->used_key_parts;
}
if (ref_key >= 0)
{
/*
We come here when there is a REF key.
*/
int order_direction;
uint used_key_parts;
if (!usable_keys.is_set(ref_key))
{
/*
We come here when ref_key is not among usable_keys
*/
uint new_ref_key;
/*
If using index only read, only consider other possible index only
keys
*/
if (table->used_keys.is_set(ref_key))
usable_keys.intersect(table->used_keys);
if ((new_ref_key= test_if_subkey(order, table, ref_key, ref_key_parts,
&usable_keys)) < MAX_KEY)
{
/* Found key that can be used to retrieve data in sorted order */
if (tab->ref.key >= 0)
{
/*
We'll use ref access method on key new_ref_key. In general case
the index search tuple for new_ref_key will be different (e.g.
when one index is defined as (part1, part2, ...) and another as
(part1, part2(N), ...) and the WHERE clause contains
"part1 = const1 AND part2=const2".
So we build tab->ref from scratch here.
*/
KEYUSE *keyuse= tab->keyuse;
while (keyuse->key != new_ref_key && keyuse->table == tab->table)
keyuse++;
if (create_ref_for_key(tab->join, tab, keyuse,
tab->join->const_table_map))
DBUG_RETURN(0);
}
else
{
/*
The range optimizer constructed QUICK_RANGE for ref_key, and
we want to use instead new_ref_key as the index. We can't
just change the index of the quick select, because this may
result in an incosistent QUICK_SELECT object. Below we
create a new QUICK_SELECT from scratch so that all its
parameres are set correctly by the range optimizer.
*/
key_map new_ref_key_map;
new_ref_key_map.clear_all(); // Force the creation of quick select
new_ref_key_map.set_bit(new_ref_key); // only for new_ref_key.
if (select->test_quick_select(tab->join->thd, new_ref_key_map, 0,
(tab->join->select_options &
OPTION_FOUND_ROWS) ?
HA_POS_ERROR :
tab->join->unit->select_limit_cnt,0) <=
0)
DBUG_RETURN(0);
}
ref_key= new_ref_key;
}
}
/* Check if we get the rows in requested sorted order by using the key */
if (usable_keys.is_set(ref_key) &&
(order_direction = test_if_order_by_key(order,table,ref_key,
&used_key_parts)))
{
if (order_direction == -1) // If ORDER BY ... DESC
{
if (select && select->quick)
{
/*
Don't reverse the sort order, if it's already done.
(In some cases test_if_order_by_key() can be called multiple times
*/
if (!select->quick->reverse_sorted())
{
// ORDER BY range_key DESC
QUICK_SELECT_DESC *tmp=new QUICK_SELECT_DESC(select->quick,
used_key_parts);
if (!tmp || tmp->error)
{
delete tmp;
DBUG_RETURN(0); // Reverse sort not supported
}
select->quick=tmp;
}
DBUG_RETURN(1);
}
if (tab->ref.key_parts < used_key_parts)
{
/*
SELECT * FROM t1 WHERE a=1 ORDER BY a DESC,b DESC
Use a traversal function that starts by reading the last row
with key part (A) and then traverse the index backwards.
*/
tab->read_first_record= join_read_last_key;
tab->read_record.read_record= join_read_prev_same;
/* fall through */
}
}
else if (select && select->quick)
select->quick->sorted= 1;
DBUG_RETURN(1); /* No need to sort */
}
}
else
{
/* check if we can use a key to resolve the group */
/* Tables using JT_NEXT are handled here */
uint nr;
key_map keys;
/*
If not used with LIMIT, only use keys if the whole query can be
resolved with a key; This is because filesort() is usually faster than
retrieving all rows through an index.
*/
if (select_limit >= table->file->records)
{
keys= *table->file->keys_to_use_for_scanning();
keys.merge(table->used_keys);
/*
We are adding here also the index specified in FORCE INDEX clause,
if any.
This is to allow users to use index in ORDER BY.
*/
if (table->force_index)
keys.merge(table->keys_in_use_for_query);
keys.intersect(usable_keys);
}
else
keys= usable_keys;
for (nr=0; nr < table->keys ; nr++)
{
uint not_used;
if (keys.is_set(nr))
{
int flag;
if ((flag= test_if_order_by_key(order, table, nr, &not_used)))
{
if (!no_changes)
{
tab->index=nr;
tab->read_first_record= (flag > 0 ? join_read_first:
join_read_last);
tab->type=JT_NEXT; // Read with index_first(), index_next()
if (table->used_keys.is_set(nr))
{
table->key_read=1;
table->file->extra(HA_EXTRA_KEYREAD);
}
}
DBUG_RETURN(1);
}
}
}
}
DBUG_RETURN(0); // Can't use index.
}
/*
If not selecting by given key, create an index how records should be read
SYNOPSIS
create_sort_index()
thd Thread handler
tab Table to sort (in join structure)
order How table should be sorted
filesort_limit Max number of rows that needs to be sorted
select_limit Max number of rows in final output
Used to decide if we should use index or not
IMPLEMENTATION
- If there is an index that can be used, 'tab' is modified to use
this index.
- If no index, create with filesort() an index file that can be used to
retrieve rows in order (should be done with 'read_record').
The sorted data is stored in tab->table and will be freed when calling
free_io_cache(tab->table).
RETURN VALUES
0 ok
-1 Some fatal error
1 No records
*/
static int
create_sort_index(THD *thd, JOIN *join, ORDER *order,
ha_rows filesort_limit, ha_rows select_limit)
{
SORT_FIELD *sortorder;
uint length;
ha_rows examined_rows;
TABLE *table;
SQL_SELECT *select;
JOIN_TAB *tab;
DBUG_ENTER("create_sort_index");
if (join->tables == join->const_tables)
DBUG_RETURN(0); // One row, no need to sort
tab= join->join_tab + join->const_tables;
table= tab->table;
select= tab->select;
if (test_if_skip_sort_order(tab,order,select_limit,0))
DBUG_RETURN(0);
if (!(sortorder=make_unireg_sortorder(order,&length)))
goto err; /* purecov: inspected */
/* It's not fatal if the following alloc fails */
table->sort.io_cache=(IO_CACHE*) my_malloc(sizeof(IO_CACHE),
MYF(MY_WME | MY_ZEROFILL));
table->status=0; // May be wrong if quick_select
// If table has a range, move it to select
if (select && !select->quick && tab->ref.key >= 0)
{
if (tab->quick)
{
select->quick=tab->quick;
tab->quick=0;
/* We can only use 'Only index' if quick key is same as ref_key */
if (table->key_read && (uint) tab->ref.key != select->quick->index)
{
table->key_read=0;
table->file->extra(HA_EXTRA_NO_KEYREAD);
}
}
else
{
/*
We have a ref on a const; Change this to a range that filesort
can use.
For impossible ranges (like when doing a lookup on NULL on a NOT NULL
field, quick will contain an empty record set.
*/
if (!(select->quick= (tab->type == JT_FT ?
new FT_SELECT(thd, table, tab->ref.key) :
get_quick_select_for_ref(thd, table, &tab->ref))))
goto err;
}
}
if (table->tmp_table)
table->file->info(HA_STATUS_VARIABLE); // Get record count
table->sort.found_records=filesort(thd, table,sortorder, length,
select, filesort_limit, &examined_rows);
tab->records= table->sort.found_records; // For SQL_CALC_ROWS
if (select)
{
select->cleanup(); // filesort did select
tab->select= 0;
}
tab->select_cond=0;
tab->type=JT_ALL; // Read with normal read_record
tab->read_first_record= join_init_read_record;
tab->join->examined_rows+=examined_rows;
if (table->key_read) // Restore if we used indexes
{
table->key_read=0;
table->file->extra(HA_EXTRA_NO_KEYREAD);
}
DBUG_RETURN(table->sort.found_records == HA_POS_ERROR);
err:
DBUG_RETURN(-1);
}
/*
Add the HAVING criteria to table->select
*/
#ifdef NOT_YET
static bool fix_having(JOIN *join, Item **having)
{
(*having)->update_used_tables(); // Some tables may have been const
JOIN_TAB *table=&join->join_tab[join->const_tables];
table_map used_tables= join->const_table_map | table->table->map;
DBUG_EXECUTE("where",print_where(*having,"having"););
Item* sort_table_cond=make_cond_for_table(*having,used_tables,used_tables);
if (sort_table_cond)
{
if (!table->select)
if (!(table->select=new SQL_SELECT))
return 1;
if (!table->select->cond)
table->select->cond=sort_table_cond;
else // This should never happen
if (!(table->select->cond= new Item_cond_and(table->select->cond,
sort_table_cond)) ||
table->select->cond->fix_fields(join->thd, join->tables_list,
&table->select->cond))
return 1;
table->select_cond=table->select->cond;
table->select_cond->top_level_item();
DBUG_EXECUTE("where",print_where(table->select_cond,
"select and having"););
*having=make_cond_for_table(*having,~ (table_map) 0,~used_tables);
DBUG_EXECUTE("where",print_where(*having,"having after make_cond"););
}
return 0;
}
#endif
/*****************************************************************************
Remove duplicates from tmp table
This should be recoded to add a unique index to the table and remove
duplicates
Table is a locked single thread table
fields is the number of fields to check (from the end)
*****************************************************************************/
static bool compare_record(TABLE *table, Field **ptr)
{
for (; *ptr ; ptr++)
{
if ((*ptr)->cmp_offset(table->rec_buff_length))
return 1;
}
return 0;
}
static bool copy_blobs(Field **ptr)
{
for (; *ptr ; ptr++)
{
if ((*ptr)->flags & BLOB_FLAG)
if (((Field_blob *) (*ptr))->copy())
return 1; // Error
}
return 0;
}
static void free_blobs(Field **ptr)
{
for (; *ptr ; ptr++)
{
if ((*ptr)->flags & BLOB_FLAG)
((Field_blob *) (*ptr))->free();
}
}
static int
remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having)
{
int error;
ulong reclength,offset;
uint field_count;
THD *thd= join->thd;
DBUG_ENTER("remove_duplicates");
entry->reginfo.lock_type=TL_WRITE;
/* Calculate how many saved fields there is in list */
field_count=0;
List_iterator<Item> it(fields);
Item *item;
while ((item=it++))
{
if (item->get_tmp_table_field() && ! item->const_item())
field_count++;
}
if (!field_count && !(join->select_options & OPTION_FOUND_ROWS))
{ // only const items with no OPTION_FOUND_ROWS
join->unit->select_limit_cnt= 1; // Only send first row
DBUG_RETURN(0);
}
Field **first_field=entry->field+entry->fields - field_count;
offset= field_count ?
entry->field[entry->fields - field_count]->offset() : 0;
reclength=entry->reclength-offset;
free_io_cache(entry); // Safety
entry->file->info(HA_STATUS_VARIABLE);
if (entry->db_type == DB_TYPE_HEAP ||
(!entry->blob_fields &&
((ALIGN_SIZE(reclength) + HASH_OVERHEAD) * entry->file->records <
thd->variables.sortbuff_size)))
error=remove_dup_with_hash_index(join->thd, entry,
field_count, first_field,
reclength, having);
else
error=remove_dup_with_compare(join->thd, entry, first_field, offset,
having);
free_blobs(first_field);
DBUG_RETURN(error);
}
static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
ulong offset, Item *having)
{
handler *file=table->file;
char *org_record,*new_record;
byte *record;
int error;
ulong reclength=table->reclength-offset;
DBUG_ENTER("remove_dup_with_compare");
org_record=(char*) (record=table->record[0])+offset;
new_record=(char*) table->record[1]+offset;
file->ha_rnd_init(1);
error=file->rnd_next(record);
for (;;)
{
if (thd->killed)
{
my_error(ER_SERVER_SHUTDOWN,MYF(0));
error=0;
goto err;
}
if (error)
{
if (error == HA_ERR_RECORD_DELETED)
continue;
if (error == HA_ERR_END_OF_FILE)
break;
goto err;
}
if (having && !having->val_int())
{
if ((error=file->delete_row(record)))
goto err;
error=file->rnd_next(record);
continue;
}
if (copy_blobs(first_field))
{
my_error(ER_OUTOFMEMORY,MYF(0));
error=0;
goto err;
}
memcpy(new_record,org_record,reclength);
/* Read through rest of file and mark duplicated rows deleted */
bool found=0;
for (;;)
{
if ((error=file->rnd_next(record)))
{
if (error == HA_ERR_RECORD_DELETED)
continue;
if (error == HA_ERR_END_OF_FILE)
break;
goto err;
}
if (compare_record(table, first_field) == 0)
{
if ((error=file->delete_row(record)))
goto err;
}
else if (!found)
{
found=1;
file->position(record); // Remember position
}
}
if (!found)
break; // End of file
/* Restart search on next row */
error=file->restart_rnd_next(record,file->ref);
}
file->extra(HA_EXTRA_NO_CACHE);
DBUG_RETURN(0);
err:
file->extra(HA_EXTRA_NO_CACHE);
if (error)
file->print_error(error,MYF(0));
DBUG_RETURN(1);
}
/*
Generate a hash index for each row to quickly find duplicate rows
Note that this will not work on tables with blobs!
*/
static int remove_dup_with_hash_index(THD *thd, TABLE *table,
uint field_count,
Field **first_field,
ulong key_length,
Item *having)
{
byte *key_buffer, *key_pos, *record=table->record[0];
int error;
handler *file= table->file;
ulong extra_length= ALIGN_SIZE(key_length)-key_length;
uint *field_lengths,*field_length;
HASH hash;
DBUG_ENTER("remove_dup_with_hash_index");
if (!my_multi_malloc(MYF(MY_WME),
&key_buffer,
(uint) ((key_length + extra_length) *
(long) file->records),
&field_lengths,
(uint) (field_count*sizeof(*field_lengths)),
NullS))
DBUG_RETURN(1);
{
Field **ptr;
ulong total_length= 0;
for (ptr= first_field, field_length=field_lengths ; *ptr ; ptr++)
{
uint length= (*ptr)->pack_length();
(*field_length++)= length;
total_length+= length;
}
DBUG_PRINT("info",("field_count: %u key_length: %lu total_length: %lu",
field_count, key_length, total_length));
DBUG_ASSERT(total_length <= key_length);
key_length= total_length;
extra_length= ALIGN_SIZE(key_length)-key_length;
}
if (hash_init(&hash, &my_charset_bin, (uint) file->records, 0,
key_length, (hash_get_key) 0, 0, 0))
{
my_free((char*) key_buffer,MYF(0));
DBUG_RETURN(1);
}
file->ha_rnd_init(1);
key_pos=key_buffer;
for (;;)
{
byte *org_key_pos;
if (thd->killed)
{
my_error(ER_SERVER_SHUTDOWN,MYF(0));
error=0;
goto err;
}
if ((error=file->rnd_next(record)))
{
if (error == HA_ERR_RECORD_DELETED)
continue;
if (error == HA_ERR_END_OF_FILE)
break;
goto err;
}
if (having && !having->val_int())
{
if ((error=file->delete_row(record)))
goto err;
continue;
}
/* copy fields to key buffer */
org_key_pos= key_pos;
field_length=field_lengths;
for (Field **ptr= first_field ; *ptr ; ptr++)
{
(*ptr)->sort_string((char*) key_pos,*field_length);
key_pos+= *field_length++;
}
/* Check if it exists before */
if (hash_search(&hash, org_key_pos, key_length))
{
/* Duplicated found ; Remove the row */
if ((error=file->delete_row(record)))
goto err;
}
else
(void) my_hash_insert(&hash, org_key_pos);
key_pos+=extra_length;
}
my_free((char*) key_buffer,MYF(0));
hash_free(&hash);
file->extra(HA_EXTRA_NO_CACHE);
(void) file->ha_rnd_end();
DBUG_RETURN(0);
err:
my_free((char*) key_buffer,MYF(0));
hash_free(&hash);
file->extra(HA_EXTRA_NO_CACHE);
(void) file->ha_rnd_end();
if (error)
file->print_error(error,MYF(0));
DBUG_RETURN(1);
}
SORT_FIELD *make_unireg_sortorder(ORDER *order, uint *length)
{
uint count;
SORT_FIELD *sort,*pos;
DBUG_ENTER("make_unireg_sortorder");
count=0;
for (ORDER *tmp = order; tmp; tmp=tmp->next)
count++;
pos=sort=(SORT_FIELD*) sql_alloc(sizeof(SORT_FIELD)*(count+1));
if (!pos)
return 0;
for (;order;order=order->next,pos++)
{
pos->field=0; pos->item=0;
if (order->item[0]->type() == Item::FIELD_ITEM)
pos->field= ((Item_field*) (*order->item))->field;
else if (order->item[0]->type() == Item::SUM_FUNC_ITEM &&
!order->item[0]->const_item())
pos->field= ((Item_sum*) order->item[0])->get_tmp_table_field();
else if (order->item[0]->type() == Item::COPY_STR_ITEM)
{ // Blob patch
pos->item= ((Item_copy_string*) (*order->item))->item;
}
else
pos->item= *order->item;
pos->reverse=! order->asc;
}
*length=count;
DBUG_RETURN(sort);
}
/*****************************************************************************
Fill join cache with packed records
Records are stored in tab->cache.buffer and last record in
last record is stored with pointers to blobs to support very big
records
******************************************************************************/
static int
join_init_cache(THD *thd,JOIN_TAB *tables,uint table_count)
{
reg1 uint i;
uint length,blobs,size;
CACHE_FIELD *copy,**blob_ptr;
JOIN_CACHE *cache;
JOIN_TAB *join_tab;
DBUG_ENTER("join_init_cache");
cache= &tables[table_count].cache;
cache->fields=blobs=0;
join_tab=tables;
for (i=0 ; i < table_count ; i++,join_tab++)
{
if (!join_tab->used_fieldlength) /* Not calced yet */
calc_used_field_length(thd, join_tab);
cache->fields+=join_tab->used_fields;
blobs+=join_tab->used_blobs;
}
if (!(cache->field=(CACHE_FIELD*)
sql_alloc(sizeof(CACHE_FIELD)*(cache->fields+table_count*2)+(blobs+1)*
sizeof(CACHE_FIELD*))))
{
my_free((gptr) cache->buff,MYF(0)); /* purecov: inspected */
cache->buff=0; /* purecov: inspected */
DBUG_RETURN(1); /* purecov: inspected */
}
copy=cache->field;
blob_ptr=cache->blob_ptr=(CACHE_FIELD**)
(cache->field+cache->fields+table_count*2);
length=0;
for (i=0 ; i < table_count ; i++)
{
uint null_fields=0,used_fields;
Field **f_ptr,*field;
for (f_ptr=tables[i].table->field,used_fields=tables[i].used_fields ;
used_fields ;
f_ptr++)
{
field= *f_ptr;
if (field->query_id == thd->query_id)
{
used_fields--;
length+=field->fill_cache_field(copy);
if (copy->blob_field)
(*blob_ptr++)=copy;
if (field->maybe_null())
null_fields++;
copy++;
}
}
/* Copy null bits from table */
if (null_fields && tables[i].table->null_fields)
{ /* must copy null bits */
copy->str=(char*) tables[i].table->null_flags;
copy->length=tables[i].table->null_bytes;
copy->strip=0;
copy->blob_field=0;
length+=copy->length;
copy++;
cache->fields++;
}
/* If outer join table, copy null_row flag */
if (tables[i].table->maybe_null)
{
copy->str= (char*) &tables[i].table->null_row;
copy->length=sizeof(tables[i].table->null_row);
copy->strip=0;
copy->blob_field=0;
length+=copy->length;
copy++;
cache->fields++;
}
}
cache->length=length+blobs*sizeof(char*);
cache->blobs=blobs;
*blob_ptr=0; /* End sequentel */
size=max(thd->variables.join_buff_size, cache->length);
if (!(cache->buff=(uchar*) my_malloc(size,MYF(0))))
DBUG_RETURN(1); /* Don't use cache */ /* purecov: inspected */
cache->end=cache->buff+size;
reset_cache_write(cache);
DBUG_RETURN(0);
}
static ulong
used_blob_length(CACHE_FIELD **ptr)
{
uint length,blob_length;
for (length=0 ; *ptr ; ptr++)
{
(*ptr)->blob_length=blob_length=(*ptr)->blob_field->get_length();
length+=blob_length;
(*ptr)->blob_field->get_ptr(&(*ptr)->str);
}
return length;
}
static bool
store_record_in_cache(JOIN_CACHE *cache)
{
uint length;
uchar *pos;
CACHE_FIELD *copy,*end_field;
bool last_record;
pos=cache->pos;
end_field=cache->field+cache->fields;
length=cache->length;
if (cache->blobs)
length+=used_blob_length(cache->blob_ptr);
if ((last_record=(length+cache->length > (uint) (cache->end - pos))))
cache->ptr_record=cache->records;
/*
There is room in cache. Put record there
*/
cache->records++;
for (copy=cache->field ; copy < end_field; copy++)
{
if (copy->blob_field)
{
if (last_record)
{
copy->blob_field->get_image((char*) pos,copy->length+sizeof(char*),
copy->blob_field->charset());
pos+=copy->length+sizeof(char*);
}
else
{
copy->blob_field->get_image((char*) pos,copy->length, // blob length
copy->blob_field->charset());
memcpy(pos+copy->length,copy->str,copy->blob_length); // Blob data
pos+=copy->length+copy->blob_length;
}
}
else
{
if (copy->strip)
{
char *str,*end;
for (str=copy->str,end= str+copy->length;
end > str && end[-1] == ' ' ;
end--) ;
length=(uint) (end-str);
memcpy(pos+2, str, length);
int2store(pos, length);
pos+= length+2;
}
else
{
memcpy(pos,copy->str,copy->length);
pos+=copy->length;
}
}
}
cache->pos=pos;
return last_record || (uint) (cache->end -pos) < cache->length;
}
static void
reset_cache_read(JOIN_CACHE *cache)
{
cache->record_nr=0;
cache->pos=cache->buff;
}
static void reset_cache_write(JOIN_CACHE *cache)
{
reset_cache_read(cache);
cache->records= 0;
cache->ptr_record= (uint) ~0;
}
static void
read_cached_record(JOIN_TAB *tab)
{
uchar *pos;
uint length;
bool last_record;
CACHE_FIELD *copy,*end_field;
last_record=tab->cache.record_nr++ == tab->cache.ptr_record;
pos=tab->cache.pos;
for (copy=tab->cache.field,end_field=copy+tab->cache.fields ;
copy < end_field;
copy++)
{
if (copy->blob_field)
{
if (last_record)
{
copy->blob_field->set_image((char*) pos,copy->length+sizeof(char*),
copy->blob_field->charset());
pos+=copy->length+sizeof(char*);
}
else
{
copy->blob_field->set_ptr((char*) pos,(char*) pos+copy->length);
pos+=copy->length+copy->blob_field->get_length();
}
}
else
{
if (copy->strip)
{
length= uint2korr(pos);
memcpy(copy->str, pos+2, length);
memset(copy->str+length, ' ', copy->length-length);
pos+= 2 + length;
}
else
{
memcpy(copy->str,pos,copy->length);
pos+=copy->length;
}
}
}
tab->cache.pos=pos;
return;
}
static bool
cmp_buffer_with_ref(JOIN_TAB *tab)
{
bool diff;
if (!(diff=tab->ref.key_err))
{
memcpy(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length);
}
if ((tab->ref.key_err= cp_buffer_from_ref(tab->join->thd, &tab->ref)) ||
diff)
return 1;
return memcmp(tab->ref.key_buff2, tab->ref.key_buff, tab->ref.key_length)
!= 0;
}
bool
cp_buffer_from_ref(THD *thd, TABLE_REF *ref)
{
enum enum_check_fields save_count_cuted_fields= thd->count_cuted_fields;
thd->count_cuted_fields= CHECK_FIELD_IGNORE;
for (store_key **copy=ref->key_copy ; *copy ; copy++)
{
if ((*copy)->copy() & 1)
{
thd->count_cuted_fields= save_count_cuted_fields;
return 1; // Something went wrong
}
}
thd->count_cuted_fields= save_count_cuted_fields;
return 0;
}
/*****************************************************************************
Group and order functions
*****************************************************************************/
/*
Find order/group item in requested columns and change the item to point at
it. If item doesn't exists, add it first in the field list
Return 0 if ok.
*/
static int
find_order_in_list(THD *thd, Item **ref_pointer_array,
TABLE_LIST *tables,ORDER *order, List<Item> &fields,
List<Item> &all_fields)
{
Item *it= *order->item;
if (it->type() == Item::INT_ITEM)
{ /* Order by position */
uint count= (uint) it->val_int();
if (!count || count > fields.elements)
{
my_printf_error(ER_BAD_FIELD_ERROR,ER(ER_BAD_FIELD_ERROR),
MYF(0), it->full_name(), thd->where);
return 1;
}
order->item= ref_pointer_array + count-1;
order->in_field_list= 1;
return 0;
}
uint counter;
bool unaliased;
Item **item= find_item_in_list(it, fields, &counter,
REPORT_EXCEPT_NOT_FOUND, &unaliased);
if (!item)
return 1;
if (item != (Item **)not_found_item)
{
/*
If we have found field not by its alias in select list but by its
original field name, we should additionaly check if we have conflict
for this name (in case if we would perform lookup in all tables).
*/
if (unaliased && !it->fixed && it->fix_fields(thd, tables, order->item))
return 1;
order->item= ref_pointer_array + counter;
order->in_field_list=1;
return 0;
}
order->in_field_list=0;
/*
We check it->fixed because Item_func_group_concat can put
arguments for which fix_fields already was called.
'it' reassigned in if condition because fix_field can change it.
*/
thd->lex->current_select->is_item_list_lookup= 1;
if (!it->fixed &&
(it->fix_fields(thd, tables, order->item) ||
(it= *order->item)->check_cols(1) ||
thd->is_fatal_error))
{
thd->lex->current_select->is_item_list_lookup= 0;
return 1; // Wrong field
}
thd->lex->current_select->is_item_list_lookup= 0;
uint el= all_fields.elements;
all_fields.push_front(it); // Add new field to field list
ref_pointer_array[el]= it;
order->item= ref_pointer_array + el;
return 0;
}
/*
Change order to point at item in select list. If item isn't a number
and doesn't exits in the select list, add it the the field list.
*/
int setup_order(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
List<Item> &fields, List<Item> &all_fields, ORDER *order)
{
thd->where="order clause";
for (; order; order=order->next)
{
if (find_order_in_list(thd, ref_pointer_array, tables, order, fields,
all_fields))
return 1;
}
return 0;
}
/*
Intitialize the GROUP BY list.
SYNOPSIS
setup_group()
thd Thread handler
ref_pointer_array We store references to all fields that was not in
'fields' here.
fields All fields in the select part. Any item in 'order'
that is part of these list is replaced by a pointer
to this fields.
all_fields Total list of all unique fields used by the select.
All items in 'order' that was not part of fields will
be added first to this list.
order The fields we should do GROUP BY on.
hidden_group_fields Pointer to flag that is set to 1 if we added any fields
to all_fields.
RETURN
0 ok
1 error (probably out of memory)
*/
int
setup_group(THD *thd, Item **ref_pointer_array, TABLE_LIST *tables,
List<Item> &fields, List<Item> &all_fields, ORDER *order,
bool *hidden_group_fields)
{
*hidden_group_fields=0;
if (!order)
return 0; /* Everything is ok */
if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
{
Item *item;
List_iterator<Item> li(fields);
while ((item=li++))
item->marker=0; /* Marker that field is not used */
}
uint org_fields=all_fields.elements;
thd->where="group statement";
for (; order; order=order->next)
{
if (find_order_in_list(thd, ref_pointer_array, tables, order, fields,
all_fields))
return 1;
(*order->item)->marker=1; /* Mark found */
if ((*order->item)->with_sum_func)
{
my_printf_error(ER_WRONG_GROUP_FIELD, ER(ER_WRONG_GROUP_FIELD),MYF(0),
(*order->item)->full_name());
return 1;
}
}
if (thd->variables.sql_mode & MODE_ONLY_FULL_GROUP_BY)
{
/* Don't allow one to use fields that is not used in GROUP BY */
Item *item;
List_iterator<Item> li(fields);
while ((item=li++))
{
if (item->type() != Item::SUM_FUNC_ITEM && !item->marker &&
!item->const_item())
{
my_printf_error(ER_WRONG_FIELD_WITH_GROUP,
ER(ER_WRONG_FIELD_WITH_GROUP),
MYF(0),item->full_name());
return 1;
}
}
}
if (org_fields != all_fields.elements)
*hidden_group_fields=1; // group fields is not used
return 0;
}
/*
Add fields with aren't used at start of field list. Return FALSE if ok
*/
static bool
setup_new_fields(THD *thd,TABLE_LIST *tables,List<Item> &fields,
List<Item> &all_fields, ORDER *new_field)
{
Item **item;
DBUG_ENTER("setup_new_fields");
thd->set_query_id=1; // Not really needed, but...
uint counter;
bool not_used;
for (; new_field ; new_field= new_field->next)
{
if ((item= find_item_in_list(*new_field->item, fields, &counter,
IGNORE_ERRORS, &not_used)))
new_field->item=item; /* Change to shared Item */
else
{
thd->where="procedure list";
if ((*new_field->item)->fix_fields(thd, tables, new_field->item))
DBUG_RETURN(1); /* purecov: inspected */
all_fields.push_front(*new_field->item);
new_field->item=all_fields.head_ref();
}
}
DBUG_RETURN(0);
}
/*
Create a group by that consist of all non const fields. Try to use
the fields in the order given by 'order' to allow one to optimize
away 'order by'.
*/
static ORDER *
create_distinct_group(THD *thd, Item **ref_pointer_array,
ORDER *order_list, List<Item> &fields,
bool *all_order_by_fields_used)
{
List_iterator<Item> li(fields);
Item *item;
ORDER *order,*group,**prev;
uint index= 0;
*all_order_by_fields_used= 1;
while ((item=li++))
item->marker=0; /* Marker that field is not used */
prev= &group; group=0;
for (order=order_list ; order; order=order->next)
{
if (order->in_field_list)
{
ORDER *ord=(ORDER*) thd->memdup((char*) order,sizeof(ORDER));
if (!ord)
return 0;
*prev=ord;
prev= &ord->next;
(*ord->item)->marker=1;
}
else
*all_order_by_fields_used= 0;
}
li.rewind();
while ((item=li++))
{
if (!item->const_item() && !item->with_sum_func && !item->marker)
{
ORDER *ord=(ORDER*) thd->calloc(sizeof(ORDER));
if (!ord)
return 0;
/*
We have here only field_list (not all_field_list), so we can use
simple indexing of ref_pointer_array (order in the array and in the
list are same)
*/
ord->item= ref_pointer_array + index;
ord->asc=1;
*prev=ord;
prev= &ord->next;
}
index++;
}
*prev=0;
return group;
}
/*****************************************************************************
Update join with count of the different type of fields
*****************************************************************************/
void
count_field_types(TMP_TABLE_PARAM *param, List<Item> &fields,
bool reset_with_sum_func)
{
List_iterator<Item> li(fields);
Item *field;
param->field_count=param->sum_func_count=param->func_count=
param->hidden_field_count=0;
param->quick_group=1;
while ((field=li++))
{
Item::Type type=field->type();
if (type == Item::FIELD_ITEM)
param->field_count++;
else if (type == Item::SUM_FUNC_ITEM)
{
if (! field->const_item())
{
Item_sum *sum_item=(Item_sum*) field;
if (!sum_item->quick_group)
param->quick_group=0; // UDF SUM function
param->sum_func_count++;
for (uint i=0 ; i < sum_item->arg_count ; i++)
{
if (sum_item->args[0]->type() == Item::FIELD_ITEM)
param->field_count++;
else
param->func_count++;
}
}
}
else
{
param->func_count++;
if (reset_with_sum_func)
field->with_sum_func=0;
}
}
}
/*
Return 1 if second is a subpart of first argument
If first parts has different direction, change it to second part
(group is sorted like order)
*/
static bool
test_if_subpart(ORDER *a,ORDER *b)
{
for (; a && b; a=a->next,b=b->next)
{
if ((*a->item)->eq(*b->item,1))
a->asc=b->asc;
else
return 0;
}
return test(!b);
}
/*
Return table number if there is only one table in sort order
and group and order is compatible
else return 0;
*/
static TABLE *
get_sort_by_table(ORDER *a,ORDER *b,TABLE_LIST *tables)
{
table_map map= (table_map) 0;
DBUG_ENTER("get_sort_by_table");
if (!a)
a=b; // Only one need to be given
else if (!b)
b=a;
for (; a && b; a=a->next,b=b->next)
{
if (!(*a->item)->eq(*b->item,1))
DBUG_RETURN(0);
map|=a->item[0]->used_tables();
}
if (!map || (map & (RAND_TABLE_BIT | OUTER_REF_TABLE_BIT)))
DBUG_RETURN(0);
for (; !(map & tables->table->map) ; tables=tables->next) ;
if (map != tables->table->map)
DBUG_RETURN(0); // More than one table
DBUG_PRINT("exit",("sort by table: %d",tables->table->tablenr));
DBUG_RETURN(tables->table);
}
/* calc how big buffer we need for comparing group entries */
static void
calc_group_buffer(JOIN *join,ORDER *group)
{
uint key_length=0, parts=0, null_parts=0;
if (group)
join->group= 1;
for (; group ; group=group->next)
{
Field *field=(*group->item)->get_tmp_table_field();
if (field)
{
if (field->type() == FIELD_TYPE_BLOB)
key_length+=MAX_BLOB_WIDTH; // Can't be used as a key
else
key_length+=field->pack_length();
}
else if ((*group->item)->result_type() == REAL_RESULT)
key_length+=sizeof(double);
else if ((*group->item)->result_type() == INT_RESULT)
key_length+=sizeof(longlong);
else
key_length+=(*group->item)->max_length;
parts++;
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;
}
/*
allocate group fields or take prepared (cached)
SYNOPSIS
make_group_fields()
main_join - join of current select
curr_join - current join (join of current select or temporary copy of it)
RETURN
0 - ok
1 - failed
*/
static bool
make_group_fields(JOIN *main_join, JOIN *curr_join)
{
if (main_join->group_fields_cache.elements)
{
curr_join->group_fields= main_join->group_fields_cache;
curr_join->sort_and_group= 1;
}
else
{
if (alloc_group_fields(curr_join, curr_join->group_list))
return (1);
main_join->group_fields_cache= curr_join->group_fields;
}
return (0);
}
/*
Get a list of buffers for saveing last group
Groups are saved in reverse order for easyer check loop
*/
static bool
alloc_group_fields(JOIN *join,ORDER *group)
{
if (group)
{
for (; group ; group=group->next)
{
Item_buff *tmp=new_Item_buff(join->thd, *group->item);
if (!tmp || join->group_fields.push_front(tmp))
return TRUE;
}
}
join->sort_and_group=1; /* Mark for do_select */
return FALSE;
}
static int
test_if_group_changed(List<Item_buff> &list)
{
DBUG_ENTER("test_if_group_changed");
List_iterator<Item_buff> li(list);
int idx= -1,i;
Item_buff *buff;
for (i=(int) list.elements-1 ; (buff=li++) ; i--)
{
if (buff->cmp())
idx=i;
}
DBUG_PRINT("info", ("idx: %d", idx));
DBUG_RETURN(idx);
}
/*
Setup copy_fields to save fields at start of new group
setup_copy_fields()
thd - THD pointer
param - temporary table parameters
ref_pointer_array - array of pointers to top elements of filed list
res_selected_fields - new list of items of select item list
res_all_fields - new list of all items
elements - number of elements in select item list
all_fields - all fields list
DESCRIPTION
Setup copy_fields to save fields at start of new group
Only FIELD_ITEM:s and FUNC_ITEM:s needs to be saved between groups.
Change old item_field to use a new field with points at saved fieldvalue
This function is only called before use of send_fields
RETURN
0 - ok
!=0 - error
*/
bool
setup_copy_fields(THD *thd, TMP_TABLE_PARAM *param,
Item **ref_pointer_array,
List<Item> &res_selected_fields, List<Item> &res_all_fields,
uint elements, List<Item> &all_fields)
{
Item *pos;
List_iterator_fast<Item> li(all_fields);
Copy_field *copy= NULL;
res_selected_fields.empty();
res_all_fields.empty();
List_iterator_fast<Item> itr(res_all_fields);
List<Item> extra_funcs;
uint i, border= all_fields.elements - elements;
DBUG_ENTER("setup_copy_fields");
if (param->field_count &&
!(copy=param->copy_field= new Copy_field[param->field_count]))
goto err2;
param->copy_funcs.empty();
for (i= 0; (pos= li++); i++)
{
if (pos->type() == Item::FIELD_ITEM)
{
Item_field *item;
if (!(item= new Item_field(thd, ((Item_field*) pos))))
goto err;
pos= item;
if (item->field->flags & BLOB_FLAG)
{
if (!(pos= new Item_copy_string(pos)))
goto err;
/*
Item_copy_string::copy for function can call
Item_copy_string::val_int for blob via Item_ref.
But if Item_copy_string::copy for blob isn't called before,
it's value will be wrong
so let's insert Item_copy_string for blobs in the beginning of
copy_funcs
(to see full test case look at having.test, BUG #4358)
*/
if (param->copy_funcs.push_front(pos))
goto err;
}
else
{
/*
set up save buffer and change result_field to point at
saved value
*/
Field *field= item->field;
item->result_field=field->new_field(thd->mem_root,field->table);
char *tmp=(char*) sql_alloc(field->pack_length()+1);
if (!tmp)
goto err;
copy->set(tmp, item->result_field);
item->result_field->move_field(copy->to_ptr,copy->to_null_ptr,1);
copy++;
}
}
else if ((pos->type() == Item::FUNC_ITEM ||
pos->type() == Item::SUBSELECT_ITEM ||
pos->type() == Item::CACHE_ITEM ||
pos->type() == Item::COND_ITEM) &&
!pos->with_sum_func)
{ // Save for send fields
/* TODO:
In most cases this result will be sent to the user.
This should be changed to use copy_int or copy_real depending
on how the value is to be used: In some cases this may be an
argument in a group function, like: IF(ISNULL(col),0,COUNT(*))
*/
if (!(pos=new Item_copy_string(pos)))
goto err;
if (i < border) // HAVING, ORDER and GROUP BY
{
if (extra_funcs.push_back(pos))
goto err;
}
else if (param->copy_funcs.push_back(pos))
goto err;
}
res_all_fields.push_back(pos);
ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
pos;
}
param->copy_field_end= copy;
for (i= 0; i < border; i++)
itr++;
itr.sublist(res_selected_fields, elements);
/*
Put elements from HAVING, ORDER BY and GROUP BY last to ensure that any
reference used in these will resolve to a item that is already calculated
*/
param->copy_funcs.concat(&extra_funcs);
DBUG_RETURN(0);
err:
if (copy)
delete [] param->copy_field;
param->copy_field=0;
err2:
DBUG_RETURN(TRUE);
}
/*
Make a copy of all simple SELECT'ed items
This is done at the start of a new group so that we can retrieve
these later when the group changes.
*/
void
copy_fields(TMP_TABLE_PARAM *param)
{
Copy_field *ptr=param->copy_field;
Copy_field *end=param->copy_field_end;
for (; ptr != end; ptr++)
(*ptr->do_copy)(ptr);
List_iterator_fast<Item> it(param->copy_funcs);
Item_copy_string *item;
while ((item = (Item_copy_string*) it++))
item->copy();
}
/*
Make an array of pointers to sum_functions to speed up sum_func calculation
SYNOPSIS
alloc_func_list()
RETURN
0 ok
1 Error
*/
bool JOIN::alloc_func_list()
{
uint func_count, group_parts;
DBUG_ENTER("alloc_func_list");
func_count= tmp_table_param.sum_func_count;
/*
If we are using rollup, we need a copy of the summary functions for
each level
*/
if (rollup.state != ROLLUP::STATE_NONE)
func_count*= (send_group_parts+1);
group_parts= send_group_parts;
/*
If distinct, reserve memory for possible
disctinct->group_by optimization
*/
if (select_distinct)
group_parts+= fields_list.elements;
/* This must use calloc() as rollup_make_fields depends on this */
sum_funcs= (Item_sum**) thd->calloc(sizeof(Item_sum**) * (func_count+1) +
sizeof(Item_sum***) * (group_parts+1));
sum_funcs_end= (Item_sum***) (sum_funcs+func_count+1);
DBUG_RETURN(sum_funcs == 0);
}
/*
Initialize 'sum_funcs' array with all Item_sum objects
SYNOPSIS
make_sum_func_list()
field_list All items
send_fields Items in select list
before_group_by Set to 1 if this is called before GROUP BY handling
NOTES
Calls ::setup() for all item_sum objects in field_list
RETURN
0 ok
1 error
*/
bool JOIN::make_sum_func_list(List<Item> &field_list, List<Item> &send_fields,
bool before_group_by)
{
List_iterator_fast<Item> it(field_list);
Item_sum **func;
Item *item;
DBUG_ENTER("make_sum_func_list");
func= sum_funcs;
while ((item=it++))
{
if (item->type() == Item::SUM_FUNC_ITEM && !item->const_item())
{
*func++= (Item_sum*) item;
/* let COUNT(DISTINCT) create the temporary table */
if (((Item_sum*) item)->setup(thd))
DBUG_RETURN(TRUE);
}
}
if (before_group_by && rollup.state == ROLLUP::STATE_INITED)
{
rollup.state= ROLLUP::STATE_READY;
if (rollup_make_fields(field_list, send_fields, &func))
DBUG_RETURN(TRUE); // Should never happen
}
else if (rollup.state == ROLLUP::STATE_NONE)
{
for (uint i=0 ; i <= send_group_parts ;i++)
sum_funcs_end[i]= func;
}
else if (rollup.state == ROLLUP::STATE_READY)
DBUG_RETURN(FALSE); // Don't put end marker
*func=0; // End marker
DBUG_RETURN(FALSE);
}
/*
Change all funcs and sum_funcs to fields in tmp table, and create
new list of all items.
change_to_use_tmp_fields()
thd - THD pointer
ref_pointer_array - array of pointers to top elements of filed list
res_selected_fields - new list of items of select item list
res_all_fields - new list of all items
elements - number of elements in select item list
all_fields - all fields list
RETURN
0 - ok
!=0 - error
*/
static bool
change_to_use_tmp_fields(THD *thd, Item **ref_pointer_array,
List<Item> &res_selected_fields,
List<Item> &res_all_fields,
uint elements, List<Item> &all_fields)
{
List_iterator_fast<Item> it(all_fields);
Item *item_field,*item;
res_selected_fields.empty();
res_all_fields.empty();
uint i, border= all_fields.elements - elements;
for (i= 0; (item= it++); i++)
{
Field *field;
if (item->with_sum_func && item->type() != Item::SUM_FUNC_ITEM)
item_field= item;
else
{
if (item->type() == Item::FIELD_ITEM)
{
item_field= item->get_tmp_table_item(thd);
}
else if ((field= item->get_tmp_table_field()))
{
if (item->type() == Item::SUM_FUNC_ITEM && field->table->group)
item_field= ((Item_sum*) item)->result_item(field);
else
item_field= (Item*) new Item_field(field);
if (!item_field)
return TRUE; // Fatal error
item_field->name= item->name; /*lint -e613 */
#ifndef DBUG_OFF
if (_db_on_ && !item_field->name)
{
char buff[256];
String str(buff,sizeof(buff),&my_charset_bin);
str.length(0);
item->print(&str);
item_field->name= sql_strmake(str.ptr(),str.length());
}
#endif
}
else
item_field= item;
}
res_all_fields.push_back(item_field);
ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
item_field;
}
List_iterator_fast<Item> itr(res_all_fields);
for (i= 0; i < border; i++)
itr++;
itr.sublist(res_selected_fields, elements);
return FALSE;
}
/*
Change all sum_func refs to fields to point at fields in tmp table
Change all funcs to be fields in tmp table
change_refs_to_tmp_fields()
thd - THD pointer
ref_pointer_array - array of pointers to top elements of filed list
res_selected_fields - new list of items of select item list
res_all_fields - new list of all items
elements - number of elements in select item list
all_fields - all fields list
RETURN
0 ok
1 error
*/
static bool
change_refs_to_tmp_fields(THD *thd, Item **ref_pointer_array,
List<Item> &res_selected_fields,
List<Item> &res_all_fields, uint elements,
List<Item> &all_fields)
{
List_iterator_fast<Item> it(all_fields);
Item *item, *new_item;
res_selected_fields.empty();
res_all_fields.empty();
uint i, border= all_fields.elements - elements;
for (i= 0; (item= it++); i++)
{
res_all_fields.push_back(new_item= item->get_tmp_table_item(thd));
ref_pointer_array[((i < border)? all_fields.elements-i-1 : i-border)]=
new_item;
}
List_iterator_fast<Item> itr(res_all_fields);
for (i= 0; i < border; i++)
itr++;
itr.sublist(res_selected_fields, elements);
return thd->is_fatal_error;
}
/******************************************************************************
Code for calculating functions
******************************************************************************/
static void
init_tmptable_sum_functions(Item_sum **func_ptr)
{
Item_sum *func;
while ((func= *(func_ptr++)))
func->reset_field();
}
/* Update record 0 in tmp_table from record 1 */
static void
update_tmptable_sum_func(Item_sum **func_ptr,
TABLE *tmp_table __attribute__((unused)))
{
Item_sum *func;
while ((func= *(func_ptr++)))
func->update_field();
}
/* Copy result of sum functions to record in tmp_table */
static void
copy_sum_funcs(Item_sum **func_ptr, Item_sum **end_ptr)
{
for (; func_ptr != end_ptr ; func_ptr++)
(void) (*func_ptr)->save_in_result_field(1);
return;
}
static bool
init_sum_functions(Item_sum **func_ptr, Item_sum **end_ptr)
{
for (; func_ptr != end_ptr ;func_ptr++)
{
if ((*func_ptr)->reset())
return 1;
}
/* If rollup, calculate the upper sum levels */
for ( ; *func_ptr ; func_ptr++)
{
if ((*func_ptr)->add())
return 1;
}
return 0;
}
static bool
update_sum_func(Item_sum **func_ptr)
{
Item_sum *func;
for (; (func= (Item_sum*) *func_ptr) ; func_ptr++)
if (func->add())
return 1;
return 0;
}
/* Copy result of functions to record in tmp_table */
void
copy_funcs(Item **func_ptr)
{
Item *func;
for (; (func = *func_ptr) ; func_ptr++)
func->save_in_result_field(1);
}
/*
Create a condition for a const reference and add this to the
currenct select for the table
*/
static bool add_ref_to_table_cond(THD *thd, JOIN_TAB *join_tab)
{
DBUG_ENTER("add_ref_to_table_cond");
if (!join_tab->ref.key_parts)
DBUG_RETURN(FALSE);
Item_cond_and *cond=new Item_cond_and();
TABLE *table=join_tab->table;
int error;
if (!cond)
DBUG_RETURN(TRUE);
for (uint i=0 ; i < join_tab->ref.key_parts ; i++)
{
Field *field=table->field[table->key_info[join_tab->ref.key].key_part[i].
fieldnr-1];
Item *value=join_tab->ref.items[i];
cond->add(new Item_func_equal(new Item_field(field), value));
}
if (thd->is_fatal_error)
DBUG_RETURN(TRUE);
if (!cond->fixed)
cond->fix_fields(thd,(TABLE_LIST *) 0, (Item**)&cond);
if (join_tab->select)
{
error=(int) cond->add(join_tab->select->cond);
join_tab->select_cond=join_tab->select->cond=cond;
}
else if ((join_tab->select=make_select(join_tab->table, 0, 0, cond,&error)))
join_tab->select_cond=cond;
DBUG_RETURN(error ? TRUE : FALSE);
}
/*
Free joins of subselect of this select.
free_underlaid_joins()
thd - THD pointer
select - pointer to st_select_lex which subselects joins we will free
*/
void free_underlaid_joins(THD *thd, SELECT_LEX *select)
{
for (SELECT_LEX_UNIT *unit= select->first_inner_unit();
unit;
unit= unit->next_unit())
unit->cleanup();
}
/****************************************************************************
ROLLUP handling
****************************************************************************/
/*
Replace occurences of group by fields in an expression by ref items
SYNOPSIS
change_group_ref()
thd reference to the context
expr expression to make replacement
group_list list of references to group by items
changed out: returns 1 if item contains a replaced field item
DESCRIPTION
The function replaces occurrences of group by fields in expr
by ref objects for these fields unless they are under aggregate
functions.
The function also corrects value of the the maybe_null attribute
for the items of all subexpressions containing group by fields.
IMPLEMENTATION
The function recursively traverses the tree of the expr expression,
looks for occurrences of the group by fields that are not under
aggregate functions and replaces them for the corresponding ref items.
NOTES
This substitution is needed GROUP BY queries with ROLLUP if
SELECT list contains expressions over group by attributes.
TODO: Some functions are not null-preserving. For those functions
updating of the maybe_null attribute is an overkill.
EXAMPLES
SELECT a+1 FROM t1 GROUP BY a WITH ROLLUP
SELECT SUM(a)+a FROM t1 GROUP BY a WITH ROLLUP
RETURN
0 if ok
1 on error
*/
static bool change_group_ref(THD *thd, Item_func *expr, ORDER *group_list,
bool *changed)
{
if (expr->arg_count)
{
Item **arg,**arg_end;
bool arg_changed= FALSE;
for (arg= expr->arguments(),
arg_end= expr->arguments()+expr->arg_count;
arg != arg_end; arg++)
{
Item *item= *arg;
if (item->type() == Item::FIELD_ITEM || item->type() == Item::REF_ITEM)
{
ORDER *group_tmp;
for (group_tmp= group_list; group_tmp; group_tmp= group_tmp->next)
{
if (item->eq(*group_tmp->item,0))
{
Item *new_item;
if(!(new_item= new Item_ref(group_tmp->item, 0, item->name)))
return 1; // fatal_error is set
thd->change_item_tree(arg, new_item);
arg_changed= TRUE;
}
}
}
else if (item->type() == Item::FUNC_ITEM)
{
if (change_group_ref(thd, (Item_func *) item, group_list, &arg_changed))
return 1;
}
}
if (arg_changed)
{
expr->maybe_null= 1;
*changed= TRUE;
}
}
return 0;
}
/* Allocate memory needed for other rollup functions */
bool JOIN::rollup_init()
{
uint i,j;
Item **ref_array;
tmp_table_param.quick_group= 0; // Can't create groups in tmp table
rollup.state= ROLLUP::STATE_INITED;
/*
Create pointers to the different sum function groups
These are updated by rollup_make_fields()
*/
tmp_table_param.group_parts= send_group_parts;
if (!(rollup.null_items= (Item_null_result**) thd->alloc((sizeof(Item*) +
sizeof(Item**) +
sizeof(List<Item>) +
ref_pointer_array_size)
* send_group_parts )))
return 1;
rollup.fields= (List<Item>*) (rollup.null_items + send_group_parts);
rollup.ref_pointer_arrays= (Item***) (rollup.fields + send_group_parts);
ref_array= (Item**) (rollup.ref_pointer_arrays+send_group_parts);
/*
Prepare space for field list for the different levels
These will be filled up in rollup_make_fields()
*/
for (i= 0 ; i < send_group_parts ; i++)
{
rollup.null_items[i]= new (thd->mem_root) Item_null_result();
List<Item> *rollup_fields= &rollup.fields[i];
rollup_fields->empty();
rollup.ref_pointer_arrays[i]= ref_array;
ref_array+= all_fields.elements;
}
for (i= 0 ; i < send_group_parts; i++)
{
for (j=0 ; j < fields_list.elements ; j++)
rollup.fields[i].push_back(rollup.null_items[i]);
}
List_iterator_fast<Item> it(all_fields);
Item *item;
while ((item= it++))
{
ORDER *group_tmp;
for (group_tmp= group_list; group_tmp; group_tmp= group_tmp->next)
{
if (*group_tmp->item == item)
item->maybe_null= 1;
}
if (item->type() == Item::FUNC_ITEM)
{
bool changed= FALSE;
if (change_group_ref(thd, (Item_func *) item, group_list, &changed))
return 1;
/*
We have to prevent creation of a field in a temporary table for
an expression that contains GROUP BY attributes.
Marking the expression item as 'with_sum_func' will ensure this.
*/
if (changed)
item->with_sum_func= 1;
}
}
return 0;
}
/*
Fill up rollup structures with pointers to fields to use
SYNOPSIS
rollup_make_fields()
fields_arg List of all fields (hidden and real ones)
sel_fields Pointer to selected fields
func Store here a pointer to all fields
IMPLEMENTATION:
Creates copies of item_sum items for each sum level
RETURN
0 if ok
In this case func is pointing to next not used element.
1 on error
*/
bool JOIN::rollup_make_fields(List<Item> &fields_arg, List<Item> &sel_fields,
Item_sum ***func)
{
List_iterator_fast<Item> it(fields_arg);
Item *first_field= sel_fields.head();
uint level;
/*
Create field lists for the different levels
The idea here is to have a separate field list for each rollup level to
avoid all runtime checks of which columns should be NULL.
The list is stored in reverse order to get sum function in such an order
in func that it makes it easy to reset them with init_sum_functions()
Assuming: SELECT a, b, c SUM(b) FROM t1 GROUP BY a,b WITH ROLLUP
rollup.fields[0] will contain list where a,b,c is NULL
rollup.fields[1] will contain list where b,c is NULL
...
rollup.ref_pointer_array[#] points to fields for rollup.fields[#]
...
sum_funcs_end[0] points to all sum functions
sum_funcs_end[1] points to all sum functions, except grand totals
...
*/
for (level=0 ; level < send_group_parts ; level++)
{
uint i;
uint pos= send_group_parts - level -1;
bool real_fields= 0;
Item *item;
List_iterator<Item> new_it(rollup.fields[pos]);
Item **ref_array_start= rollup.ref_pointer_arrays[pos];
ORDER *start_group;
/* Point to first hidden field */
Item **ref_array= ref_array_start + fields_arg.elements-1;
/* Remember where the sum functions ends for the previous level */
sum_funcs_end[pos+1]= *func;
/* Find the start of the group for this level */
for (i= 0, start_group= group_list ;
i++ < pos ;
start_group= start_group->next)
;
it.rewind();
while ((item= it++))
{
if (item == first_field)
{
real_fields= 1; // End of hidden fields
ref_array= ref_array_start;
}
if (item->type() == Item::SUM_FUNC_ITEM && !item->const_item())
{
/*
This is a top level summary function that must be replaced with
a sum function that is reset for this level.
NOTE: This code creates an object which is not that nice in a
sub select. Fortunately it's not common to have rollup in
sub selects.
*/
item= item->copy_or_same(thd);
((Item_sum*) item)->make_unique();
if (((Item_sum*) item)->setup(thd))
return 1;
*(*func)= (Item_sum*) item;
(*func)++;
}
else
{
/* Check if this is something that is part of this group by */
ORDER *group_tmp;
for (group_tmp= start_group, i= pos ;
group_tmp ; group_tmp= group_tmp->next, i++)
{
if (*group_tmp->item == item)
{
/*
This is an element that is used by the GROUP BY and should be
set to NULL in this level
*/
Item_null_result *null_item;
item->maybe_null= 1; // Value will be null sometimes
null_item= rollup.null_items[i];
null_item->result_field= item->get_tmp_table_field();
item= null_item;
break;
}
}
}
*ref_array= item;
if (real_fields)
{
(void) new_it++; // Point to next item
new_it.replace(item); // Replace previous
ref_array++;
}
else
ref_array--;
}
}
sum_funcs_end[0]= *func; // Point to last function
return 0;
}
/*
Send all rollup levels higher than the current one to the client
SYNOPSIS:
rollup_send_data()
idx Level we are on:
0 = Total sum level
1 = First group changed (a)
2 = Second group changed (a,b)
SAMPLE
SELECT a, b, c SUM(b) FROM t1 GROUP BY a,b WITH ROLLUP
RETURN
0 ok
1 If send_data_failed()
*/
int JOIN::rollup_send_data(uint idx)
{
uint i;
for (i= send_group_parts ; i-- > idx ; )
{
/* Get reference pointers to sum functions in place */
memcpy((char*) ref_pointer_array,
(char*) rollup.ref_pointer_arrays[i],
ref_pointer_array_size);
if ((!having || having->val_int()))
{
if (send_records < unit->select_limit_cnt && do_send_rows &&
result->send_data(rollup.fields[i]))
return 1;
send_records++;
}
}
/* Restore ref_pointer_array */
set_items_ref_array(current_ref_pointer_array);
return 0;
}
/*
Write all rollup levels higher than the current one to a temp table
SYNOPSIS:
rollup_write_data()
idx Level we are on:
0 = Total sum level
1 = First group changed (a)
2 = Second group changed (a,b)
table reference to temp table
SAMPLE
SELECT a, b, SUM(c) FROM t1 GROUP BY a,b WITH ROLLUP
RETURN
0 ok
1 if write_data_failed()
*/
int JOIN::rollup_write_data(uint idx, TABLE *table)
{
uint i;
for (i= send_group_parts ; i-- > idx ; )
{
/* Get reference pointers to sum functions in place */
memcpy((char*) ref_pointer_array,
(char*) rollup.ref_pointer_arrays[i],
ref_pointer_array_size);
if ((!having || having->val_int()))
{
int error;
Item *item;
List_iterator_fast<Item> it(rollup.fields[i]);
while ((item= it++))
{
if (item->type() == Item::NULL_ITEM && item->is_result_field())
item->save_in_result_field(1);
}
copy_sum_funcs(sum_funcs_end[i+1], sum_funcs_end[i]);
if ((error= table->file->write_row(table->record[0])))
{
if (create_myisam_from_heap(thd, table, &tmp_table_param,
error, 0))
return 1;
}
}
}
/* Restore ref_pointer_array */
set_items_ref_array(current_ref_pointer_array);
return 0;
}
/*
clear results if there are not rows found for group
(end_send_group/end_write_group)
SYNOPSYS
JOIN::clear()
*/
void JOIN::clear()
{
clear_tables(this);
copy_fields(&tmp_table_param);
if (sum_funcs)
{
Item_sum *func, **func_ptr= sum_funcs;
while ((func= *(func_ptr++)))
func->clear();
}
}
/****************************************************************************
EXPLAIN handling
Send a description about what how the select will be done to stdout
****************************************************************************/
static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
bool distinct,const char *message)
{
List<Item> field_list;
List<Item> item_list;
THD *thd=join->thd;
select_result *result=join->result;
Item *item_null= new Item_null();
CHARSET_INFO *cs= system_charset_info;
DBUG_ENTER("select_describe");
DBUG_PRINT("info", ("Select 0x%lx, type %s, message %s",
(ulong)join->select_lex, join->select_lex->type,
message ? message : "NULL"));
/* Don't log this into the slow query log */
thd->server_status&= ~(SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED);
join->unit->offset_limit_cnt= 0;
if (message)
{
item_list.push_back(new Item_int((int32)
join->select_lex->select_number));
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type), cs));
for (uint i=0 ; i < 7; i++)
item_list.push_back(item_null);
item_list.push_back(new Item_string(message,strlen(message),cs));
if (result->send_data(item_list))
join->error= 1;
}
else if (join->select_lex == join->unit->fake_select_lex)
{
/*
here we assume that the query will return at least two rows, so we
show "filesort" in EXPLAIN. Of course, sometimes we'll be wrong
and no filesort will be actually done, but executing all selects in
the UNION to provide precise EXPLAIN information will hardly be
appreciated :)
*/
char table_name_buffer[NAME_LEN];
item_list.empty();
/* id */
item_list.push_back(new Item_null);
/* select_type */
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type),
cs));
/* table */
{
SELECT_LEX *sl= join->unit->first_select();
uint len= 6, lastop= 0;
memcpy(table_name_buffer, "<union", 6);
for (; sl && len + lastop + 5 < NAME_LEN; sl= sl->next_select())
{
len+= lastop;
lastop= my_snprintf(table_name_buffer + len, NAME_LEN - len,
"%u,", sl->select_number);
}
if (sl || len + lastop >= NAME_LEN)
{
memcpy(table_name_buffer + len, "...>", 5);
len+= 4;
}
else
{
len+= lastop;
table_name_buffer[len - 1]= '>'; // change ',' to '>'
}
item_list.push_back(new Item_string(table_name_buffer, len, cs));
}
/* type */
item_list.push_back(new Item_string(join_type_str[JT_ALL],
strlen(join_type_str[JT_ALL]),
cs));
/* possible_keys */
item_list.push_back(item_null);
/* key*/
item_list.push_back(item_null);
/* key_len */
item_list.push_back(item_null);
/* ref */
item_list.push_back(item_null);
/* rows */
item_list.push_back(item_null);
/* extra */
if (join->unit->global_parameters->order_list.first)
item_list.push_back(new Item_string("Using filesort",
14, cs));
else
item_list.push_back(new Item_string("", 0, cs));
if (result->send_data(item_list))
join->error= 1;
}
else
{
table_map used_tables=0;
for (uint i=0 ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
TABLE *table=tab->table;
char buff[512],*buff_ptr=buff;
char buff1[512], buff2[512];
char table_name_buffer[NAME_LEN];
String tmp1(buff1,sizeof(buff1),cs);
String tmp2(buff2,sizeof(buff2),cs);
tmp1.length(0);
tmp2.length(0);
item_list.empty();
/* id */
item_list.push_back(new Item_uint((uint32)
join->select_lex->select_number));
/* select_type */
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type),
cs));
if (tab->type == JT_ALL && tab->select && tab->select->quick)
tab->type= JT_RANGE;
/* table */
if (table->derived_select_number)
{
/* Derived table name generation */
int len= my_snprintf(table_name_buffer, sizeof(table_name_buffer)-1,
"<derived%u>",
table->derived_select_number);
item_list.push_back(new Item_string(table_name_buffer, len, cs));
}
else
item_list.push_back(new Item_string(table->table_name,
strlen(table->table_name),
cs));
/* type */
item_list.push_back(new Item_string(join_type_str[tab->type],
strlen(join_type_str[tab->type]),
cs));
uint j;
/* possible_keys */
if (!tab->keys.is_clear_all())
{
for (j=0 ; j < table->keys ; j++)
{
if (tab->keys.is_set(j))
{
if (tmp1.length())
tmp1.append(',');
tmp1.append(table->key_info[j].name,
strlen(table->key_info[j].name),
system_charset_info);
}
}
}
if (tmp1.length())
item_list.push_back(new Item_string(tmp1.ptr(),tmp1.length(),cs));
else
item_list.push_back(item_null);
/* key key_len ref */
if (tab->ref.key_parts)
{
KEY *key_info=table->key_info+ tab->ref.key;
item_list.push_back(new Item_string(key_info->name,
strlen(key_info->name),
system_charset_info));
item_list.push_back(new Item_int((int32) tab->ref.key_length));
for (store_key **ref=tab->ref.key_copy ; *ref ; ref++)
{
if (tmp2.length())
tmp2.append(',');
tmp2.append((*ref)->name(), strlen((*ref)->name()),
system_charset_info);
}
item_list.push_back(new Item_string(tmp2.ptr(),tmp2.length(),cs));
}
else if (tab->type == JT_NEXT)
{
KEY *key_info=table->key_info+ tab->index;
item_list.push_back(new Item_string(key_info->name,
strlen(key_info->name),cs));
item_list.push_back(new Item_int((int32) key_info->key_length));
item_list.push_back(item_null);
}
else if (tab->select && tab->select->quick)
{
KEY *key_info=table->key_info+ tab->select->quick->index;
item_list.push_back(new Item_string(key_info->name,
strlen(key_info->name),cs));
item_list.push_back(new Item_int((int32) tab->select->quick->
max_used_key_length));
item_list.push_back(item_null);
}
else
{
item_list.push_back(item_null);
item_list.push_back(item_null);
item_list.push_back(item_null);
}
/* rows */
item_list.push_back(new Item_int((longlong) (ulonglong)
join->best_positions[i]. records_read,
21));
/* extra */
my_bool key_read=table->key_read;
if ((tab->type == JT_NEXT || tab->type == JT_CONST) &&
table->used_keys.is_set(tab->index))
key_read=1;
if (tab->info)
item_list.push_back(new Item_string(tab->info,strlen(tab->info),cs));
else
{
if (tab->select)
{
if (tab->use_quick == 2)
{
char buf[MAX_KEY/8+1];
sprintf(buff_ptr,"; Range checked for each record (index map: 0x%s)",
tab->keys.print(buf));
buff_ptr=strend(buff_ptr);
}
else
buff_ptr=strmov(buff_ptr,"; Using where");
}
if (key_read)
buff_ptr= strmov(buff_ptr,"; Using index");
if (table->reginfo.not_exists_optimize)
buff_ptr= strmov(buff_ptr,"; Not exists");
if (need_tmp_table)
{
need_tmp_table=0;
buff_ptr= strmov(buff_ptr,"; Using temporary");
}
if (need_order)
{
need_order=0;
buff_ptr= strmov(buff_ptr,"; Using filesort");
}
if (distinct & test_all_bits(used_tables,thd->used_tables))
buff_ptr= strmov(buff_ptr,"; Distinct");
if (buff_ptr == buff)
buff_ptr+= 2; // Skip inital "; "
item_list.push_back(new Item_string(buff+2,(uint) (buff_ptr - buff)-2,
cs));
}
// For next iteration
used_tables|=table->map;
if (result->send_data(item_list))
join->error= 1;
}
}
for (SELECT_LEX_UNIT *unit= join->select_lex->first_inner_unit();
unit;
unit= unit->next_unit())
{
if (mysql_explain_union(thd, unit, result))
DBUG_VOID_RETURN;
}
DBUG_VOID_RETURN;
}
int mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
{
DBUG_ENTER("mysql_explain_union");
int res= 0;
SELECT_LEX *first= unit->first_select();
for (SELECT_LEX *sl= first;
sl;
sl= sl->next_select())
{
// drop UNCACHEABLE_EXPLAIN, because it is for internal usage only
uint8 uncacheable= (sl->uncacheable & ~UNCACHEABLE_EXPLAIN);
sl->type= (((&thd->lex->select_lex)==sl)?
((thd->lex->all_selects_list != sl) ?
primary_key_name : "SIMPLE"):
((sl == first)?
((sl->linkage == DERIVED_TABLE_TYPE) ?
"DERIVED":
((uncacheable & UNCACHEABLE_DEPENDENT) ?
"DEPENDENT SUBQUERY":
(uncacheable?"UNCACHEABLE SUBQUERY":
"SUBQUERY"))):
((uncacheable & UNCACHEABLE_DEPENDENT) ?
"DEPENDENT UNION":
uncacheable?"UNCACHEABLE UNION":
"UNION")));
sl->options|= SELECT_DESCRIBE;
}
if (first->next_select())
{
unit->fake_select_lex->select_number= UINT_MAX; // jost for initialization
unit->fake_select_lex->type= "UNION RESULT";
unit->fake_select_lex->options|= SELECT_DESCRIBE;
if (!(res= unit->prepare(thd, result, SELECT_NO_UNLOCK | SELECT_DESCRIBE,
"")))
res= unit->exec();
res|= unit->cleanup();
}
else
{
thd->lex->current_select= first;
res= mysql_select(thd, &first->ref_pointer_array,
(TABLE_LIST*) first->table_list.first,
first->with_wild, first->item_list,
first->where,
first->order_list.elements +
first->group_list.elements,
(ORDER*) first->order_list.first,
(ORDER*) first->group_list.first,
first->having,
(ORDER*) thd->lex->proc_list.first,
first->options | thd->options | SELECT_DESCRIBE,
result, unit, first);
}
if (res > 0 || thd->net.report_error)
res= -1; // mysql_explain_select do not report error
DBUG_RETURN(res);
}
void st_select_lex::print(THD *thd, String *str)
{
if (!thd)
thd= current_thd;
str->append("select ", 7);
//options
if (options & SELECT_STRAIGHT_JOIN)
str->append("straight_join ", 14);
if ((thd->lex->lock_option == TL_READ_HIGH_PRIORITY) &&
(this == &thd->lex->select_lex))
str->append("high_priority ", 14);
if (options & SELECT_DISTINCT)
str->append("distinct ", 9);
if (options & SELECT_SMALL_RESULT)
str->append("sql_small_result ", 17);
if (options & SELECT_BIG_RESULT)
str->append("sql_big_result ", 15);
if (options & OPTION_BUFFER_RESULT)
str->append("sql_buffer_result ", 18);
if (options & OPTION_FOUND_ROWS)
str->append("sql_calc_found_rows ", 20);
if (!thd->lex->safe_to_cache_query)
str->append("sql_no_cache ", 13);
if (options & OPTION_TO_QUERY_CACHE)
str->append("sql_cache ", 10);
//Item List
bool first= 1;
List_iterator_fast<Item> it(item_list);
Item *item;
while ((item= it++))
{
if (first)
first= 0;
else
str->append(',');
item->print_item_w_name(str);
}
/*
from clause
TODO: support USING/FORCE/IGNORE index
*/
if (table_list.elements)
{
str->append(" from ", 6);
Item *next_on= 0;
for (TABLE_LIST *table= (TABLE_LIST *) table_list.first;
table;
table= table->next)
{
if (table->derived)
{
str->append('(');
table->derived->print(str);
str->append(") ");
str->append(table->alias);
}
else
{
str->append(table->db);
str->append('.');
str->append(table->real_name);
if (my_strcasecmp(table_alias_charset, table->real_name, table->alias))
{
str->append(' ');
str->append(table->alias);
}
}
if (table->on_expr && ((table->outer_join & JOIN_TYPE_LEFT) ||
!(table->outer_join & JOIN_TYPE_RIGHT)))
next_on= table->on_expr;
if (next_on)
{
str->append(" on(", 4);
next_on->print(str);
str->append(')');
next_on= 0;
}
TABLE_LIST *next_table;
if ((next_table= table->next))
{
if (table->outer_join & JOIN_TYPE_RIGHT)
{
str->append(" right join ", 12);
if (!(table->outer_join & JOIN_TYPE_LEFT) &&
table->on_expr)
next_on= table->on_expr;
}
else if (next_table->straight)
str->append(" straight_join ", 15);
else if (next_table->outer_join & JOIN_TYPE_LEFT)
str->append(" left join ", 11);
else
str->append(" join ", 6);
}
}
}
// Where
Item *cur_where= where;
if (join)
cur_where= join->conds;
if (cur_where)
{
str->append(" where ", 7);
cur_where->print(str);
}
// group by & olap
if (group_list.elements)
{
str->append(" group by ", 10);
print_order(str, (ORDER *) group_list.first);
switch (olap)
{
case CUBE_TYPE:
str->append(" with cube", 10);
break;
case ROLLUP_TYPE:
str->append(" with rollup", 12);
break;
default:
; //satisfy compiler
}
}
// having
Item *cur_having= having;
if (join)
cur_having= join->having;
if (cur_having)
{
str->append(" having ", 8);
cur_having->print(str);
}
if (order_list.elements)
{
str->append(" order by ", 10);
print_order(str, (ORDER *) order_list.first);
}
// limit
print_limit(thd, str);
// PROCEDURE unsupported here
}
/*
change select_result object of JOIN
SYNOPSIS
JOIN::change_result()
res new select_result object
RETURN
0 - OK
-1 - error
*/
int JOIN::change_result(select_result *res)
{
DBUG_ENTER("JOIN::change_result");
result= res;
if (!procedure && result->prepare(fields_list, select_lex->master_unit()))
{
DBUG_RETURN(-1);
}
DBUG_RETURN(0);
}