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MWL#110: Make EXPLAIN always show materialization separately

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- Add Item_in_subselect::get_identifier() that returns subquery's id
- Change select_describe() to produce output in new format
- Update test results (checked)
This commit is contained in:
Sergey Petrunya
2010-03-29 18:04:35 +04:00
parent 218310b162
commit 8a06a7e3a7
11 changed files with 246 additions and 82 deletions
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116
sql/sql_select.cc
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@ -17889,8 +17889,15 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
else
{
table_map used_tables=0;
uint last_sjm_table= MAX_TABLES;
for (uint i=0 ; i < join->tables ; i++)
uchar sjm_nests[MAX_TABLES];
uint sjm_nests_cur=0;
uint sjm_nests_end= 0;
uint end_table= join->tables;
bool printing_materialize_nest= FALSE;
uint select_id= join->select_lex->select_number;
for (uint i=0 ; i < end_table ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
TABLE *table=tab->table;
@ -17898,6 +17905,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
char buff[512];
char buff1[512], buff2[512], buff3[512];
char keylen_str_buf[64];
my_bool key_read;
String extra(buff, sizeof(buff),cs);
char table_name_buffer[NAME_LEN];
String tmp1(buff1,sizeof(buff1),cs);
@ -17907,7 +17915,6 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
tmp1.length(0);
tmp2.length(0);
tmp3.length(0);
quick_type= -1;
/* Don't show eliminated tables */
@ -17919,12 +17926,89 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
item_list.empty();
/* id */
item_list.push_back(new Item_uint((uint32)
join->select_lex->select_number));
item_list.push_back(new Item_uint((uint32)select_id));
/* select_type */
item_list.push_back(new Item_string(join->select_lex->type,
strlen(join->select_lex->type),
cs));
const char* stype= printing_materialize_nest? "SUBQUERY" :
join->select_lex->type;
item_list.push_back(new Item_string(stype, strlen(stype), cs));
/*
Special processing for SJ-Materialization nests: print the fake table
and delay printing of the SJM nest contents until later.
*/
uint sj_strategy= join->best_positions[i].sj_strategy;
if (sj_is_materialize_strategy(sj_strategy) &&
!printing_materialize_nest)
{
/* table */
int len= my_snprintf(table_name_buffer,
sizeof(table_name_buffer)-1,
"subselect%d",
tab->emb_sj_nest->sj_subq_pred->get_identifier());
item_list.push_back(new Item_string(table_name_buffer, len, cs));
/* partitions */
if (join->thd->lex->describe & DESCRIBE_PARTITIONS)
item_list.push_back(item_null);
/* type */
uint type= (sj_strategy == SJ_OPT_MATERIALIZE_SCAN)? JT_ALL : JT_EQ_REF;
item_list.push_back(new Item_string(join_type_str[type],
strlen(join_type_str[type]),
cs));
/* possible_keys */
item_list.push_back(new Item_string("unique_key",
strlen("unique_key"), cs));
if (sj_strategy == SJ_OPT_MATERIALIZE_SCAN)
{
item_list.push_back(item_null); /* key */
item_list.push_back(item_null); /* key_len */
item_list.push_back(item_null); /* ref */
}
else
{
/* key */
item_list.push_back(new Item_string("unique_key", strlen("unique_key"), cs));
/* key_len */
uint klen= tab->emb_sj_nest->sj_mat_info->table->key_info[0].key_length;
uint buflen= longlong2str(klen, keylen_str_buf, 10) - keylen_str_buf;
item_list.push_back(new Item_string(keylen_str_buf, buflen, cs));
/* ref */
item_list.push_back(new Item_string("func", strlen("func"), cs));
}
/* rows */
ha_rows rows= (sj_strategy == SJ_OPT_MATERIALIZE_SCAN)?
tab->emb_sj_nest->sj_mat_info->rows : 1;
item_list.push_back(new Item_int(rows));
/* filtered */
if (join->thd->lex->describe & DESCRIBE_EXTENDED)
item_list.push_back(new Item_float(1.0, 2));
/* Extra */
if (need_tmp_table)
{
need_tmp_table=0;
extra.append(STRING_WITH_LEN("; Using temporary"));
}
if (need_order)
{
need_order=0;
extra.append(STRING_WITH_LEN("; Using filesort"));
}
/* Skip initial "; "*/
const char *str= extra.ptr();
uint32 extra_len= extra.length();
if (extra_len)
{
str += 2;
extra_len -= 2;
}
item_list.push_back(new Item_string(str, extra_len, cs));
/* Register the nest for further processing: */
sjm_nests[sjm_nests_end++]= i;
i += join->best_positions[i].n_sj_tables-1;
goto loop_end;
}
if (tab->type == JT_ALL && tab->select && tab->select->quick)
{
quick_type= tab->select->quick->get_type();
@ -17935,6 +18019,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
else
tab->type = JT_RANGE;
}
/* table */
if (table->derived_select_number)
{
@ -18113,7 +18198,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
}
/* Build "Extra" field and add it to item_list. */
my_bool key_read=table->key_read;
key_read=table->key_read;
if ((tab->type == JT_NEXT || tab->type == JT_CONST) &&
table->covering_keys.is_set(tab->index))
key_read=1;
@ -18269,7 +18354,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
extra.append(STRING_WITH_LEN(")"));
}
}
uint sj_strategy= join->best_positions[i].sj_strategy;
/*
if (sj_is_materialize_strategy(sj_strategy))
{
if (join->best_positions[i].n_sj_tables == 1)
@ -18286,6 +18372,7 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
{
extra.append(STRING_WITH_LEN("; End materialize"));
}
*/
for (uint part= 0; part < tab->ref.key_parts; part++)
{
@ -18309,6 +18396,15 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
}
item_list.push_back(new Item_string(str, len, cs));
}
loop_end:
if (i+1 == end_table && sjm_nests_cur != sjm_nests_end)
{
printing_materialize_nest= TRUE;
i= sjm_nests[sjm_nests_cur++] - 1;
end_table= (i+1) + join->best_positions[i+1].n_sj_tables;
select_id= join->join_tab[i+1].emb_sj_nest->sj_subq_pred->get_identifier();
}
// For next iteration
used_tables|=table->map;
if (result->send_data(item_list))