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EXPLAIN UNION using same routing which used for execution which allow return correct bug messages (Bug #3639)

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EXPLAIN of hidden SELECT of UNION
This commit is contained in:
bell@sanja.is.com.ua
2004-05-06 20:40:21 +03:00
parent ec33d794d8
commit 3aae50e8c0
11 changed files with 179 additions and 74 deletions
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147
sql/sql_select.cc
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@ -991,7 +991,7 @@ JOIN::optimize()
}
}
if (select_lex->master_unit()->uncacheable)
if (select_lex->master_unit()->uncacheable || thd->lex->describe)
{
if (!(tmp_join= (JOIN*)thd->alloc(sizeof(JOIN))))
DBUG_RETURN(-1);
@ -9132,7 +9132,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
if (message)
{
item_list.push_back(new Item_int((int32) join->select_lex->select_number));
item_list.push_back(new Item_int((longlong)
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++)
@ -9141,6 +9142,49 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
if (result->send_data(item_list))
join->error= 1;
}
else if (join->select_lex == join->unit->fake_select_lex)
{
/*
Here is guessing about fake_select_lex to avoid union SELECT
execution to get accurate information
*/
char table_name_buffer[64];
item_list.empty();
/* id */
item_list.push_back(new Item_int((int32)
join->select_lex->select_number));
/* select_type */
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type),
cs));
/* table */
int len= my_snprintf(table_name_buffer, sizeof(table_name_buffer)-1,
"<union%d>",
-join->select_lex->select_number);
item_list.push_back(new Item_string(table_name_buffer, len, cs));
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;
@ -9150,36 +9194,41 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
TABLE *table=tab->table;
char buff[512],*buff_ptr=buff;
char buff1[512], buff2[512];
char derived_name[64];
char table_name_buffer[64];
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_int((int32)
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(derived_name, sizeof(derived_name)-1,
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(derived_name, len, cs));
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++)
@ -9196,6 +9245,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
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;
@ -9234,9 +9284,11 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
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))
@ -9301,32 +9353,53 @@ 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);
res= mysql_explain_select(thd, sl,
(((&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"))),
result);
if (res)
break;
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= -first->select_number;
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
@ -9334,30 +9407,6 @@ int mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
}
int mysql_explain_select(THD *thd, SELECT_LEX *select_lex, char const *type,
select_result *result)
{
DBUG_ENTER("mysql_explain_select");
DBUG_PRINT("info", ("Select 0x%lx, type %s", (ulong)select_lex, type))
select_lex->type= type;
thd->lex->current_select= select_lex;
SELECT_LEX_UNIT *unit= select_lex->master_unit();
int res= mysql_select(thd, &select_lex->ref_pointer_array,
(TABLE_LIST*) select_lex->table_list.first,
select_lex->with_wild, select_lex->item_list,
select_lex->where,
select_lex->order_list.elements +
select_lex->group_list.elements,
(ORDER*) select_lex->order_list.first,
(ORDER*) select_lex->group_list.first,
select_lex->having,
(ORDER*) thd->lex->proc_list.first,
select_lex->options | thd->options | SELECT_DESCRIBE,
result, unit, select_lex);
DBUG_RETURN(res);
}
void st_select_lex::print(THD *thd, String *str)
{
if (!thd)