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Commit ab70b76d authored by Sergey Petrunya's avatar Sergey Petrunya
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BUG#992942 & MDEV-325: Pre-liminary commit for testing

parent 678b4f5d
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Showing with 250 additions and 12 deletions
mysql-test/r/show_explain.result
View file @ ab70b76d
......@@ -825,9 +825,67 @@ pk data
19 data1
20 data1
drop table t1;
drop table t0;
#
# Check that the I_S table is invisible
#
select table_name from information_schema.tables where table_schema='information_schema' and table_name like '%explain%';
table_name
#
# MDEV-325: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN is different from standard EXPLAIN: type ALL vs 'index_merge'..
#
CREATE TABLE t1 (a INT, b INT, KEY(a), KEY(b)) ENGINE=MyISAM;
INSERT INTO t1 VALUES
(8,0),(128,5050),(5372,8),(234,7596),(2,0),(2907,8930),(1,0),
(0,5224),(8,7638),(960,5),(9872,1534),(0,2295),(3408,9809),
(7,0),(1168,0),(2089,5570),(0,205),(88,1018),(0,26528),
(0,0),(4,5567),(1444,145),(6,0),(1,7535),(7793,534),(70,9),
(178,1),(44,5),(189,0),(3,0);
EXPLAIN
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index_merge a,b a,b 5,5 NULL 8 Using sort_union(a,b); Using where; Using filesort
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index_merge a,b a,b 5,5 NULL 8 Using sort_union(a,b); Using where; Using filesort
Warnings:
Note 1003 SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b
a+SLEEP(0.01)
0
5372
70
0
0
0
0
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_do_select';
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
show explain for $thr2;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t1 index_merge a,b a,b 5,5 NULL 8 Using sort_union(a,b); Using where; Using filesort
Warnings:
Note 1003 SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b
a+SLEEP(0.01)
0
5372
70
0
0
0
0
set debug_dbug='';
drop table t1;
drop table t0;
mysql-test/t/show_explain.test
View file @ ab70b76d
......@@ -837,6 +837,7 @@ select * from t1 where pk between 10 and 20 for update;
# run SHOW EXPLAIN on a frozen thread
connection default;
let $save_wait_condition= $wait_condition;
let $wait_condition= select State='Sending data' from information_schema.processlist where id=$thr2;
let $thr_default=`select connection_id()`;
--source include/wait_condition.inc
......@@ -864,14 +865,59 @@ reap;
drop table t1;
disconnect con3;
disconnect con2;
## TODO: Test this: have several SHOW EXPLAIN requests be queued up for a
## thread and served together.
drop table t0;
let $wait_condition= $save_wait_condition;
--echo #
--echo # Check that the I_S table is invisible
--echo #
select table_name from information_schema.tables where table_schema='information_schema' and table_name like '%explain%';
--echo #
--echo # MDEV-325: SHOW EXPLAIN: Plan produced by SHOW EXPLAIN is different from standard EXPLAIN: type ALL vs 'index_merge'..
--echo #
CREATE TABLE t1 (a INT, b INT, KEY(a), KEY(b)) ENGINE=MyISAM;
INSERT INTO t1 VALUES
(8,0),(128,5050),(5372,8),(234,7596),(2,0),(2907,8930),(1,0),
(0,5224),(8,7638),(960,5),(9872,1534),(0,2295),(3408,9809),
(7,0),(1168,0),(2089,5570),(0,205),(88,1018),(0,26528),
(0,0),(4,5567),(1444,145),(6,0),(1,7535),(7793,534),(70,9),
(178,1),(44,5),(189,0),(3,0);
EXPLAIN
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_join_exec_start';
--send
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set @show_explain_probe_select_id=1;
set debug_dbug='d,show_explain_probe_do_select';
--send
SELECT a+SLEEP(0.01) FROM t1
WHERE a IN ( 255, 0 ) OR b BETWEEN 6 AND 129
ORDER BY b;
connection default;
--source include/wait_condition.inc
evalp show explain for $thr2;
connection con1;
reap;
set debug_dbug='';
drop table t1;
drop table t0;
sql/sql_select.cc
View file @ ab70b76d
......@@ -10686,6 +10686,9 @@ void JOIN::cleanup(bool full)
*/
if (full)
{
if (pre_sort_join_tab)
clean_pre_sort_join_tab();
if (tmp_join)
tmp_table_param.copy_field= 0;
group_fields.delete_elements();
......@@ -18908,6 +18911,8 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
TABLE *table;
SQL_SELECT *select;
JOIN_TAB *tab;
int err= 0;
bool quick_created= FALSE;
DBUG_ENTER("create_sort_index");
if (join->table_count == join->const_tables)
......@@ -18915,6 +18920,43 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
tab= join->join_tab + join->const_tables;
table= tab->table;
select= tab->select;
JOIN_TAB *save_pre_sort_join_tab= NULL;
if (join->pre_sort_join_tab)
{
/*
we've already been in this function, and stashed away the original access
method in join->pre_sort_join_tab, restore it now.
*/
/* First, restore state of the handler */
if (join->pre_sort_index != MAX_KEY)
{
if (table->file->ha_index_or_rnd_end())
goto err;
if (join->pre_sort_idx_pushed_cond)
{
table->file->idx_cond_push(join->pre_sort_index,
join->pre_sort_idx_pushed_cond);
}
}
else
{
if (table->file->ha_index_or_rnd_end() ||
table->file->ha_rnd_init(TRUE))
goto err;
}
/* Second, restore access method parameters */
tab->records= join->pre_sort_join_tab->records;
tab->select= join->pre_sort_join_tab->select;
tab->select_cond= join->pre_sort_join_tab->select_cond;
tab->type= join->pre_sort_join_tab->type;
tab->read_first_record= join->pre_sort_join_tab->read_first_record;
save_pre_sort_join_tab= join->pre_sort_join_tab;
join->pre_sort_join_tab= NULL;
}
/* Currently ORDER BY ... LIMIT is not supported in subqueries. */
DBUG_ASSERT(join->group_list || !join->is_in_subquery());
......@@ -18970,6 +19012,7 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
get_quick_select_for_ref(thd, table, &tab->ref,
tab->found_records))))
goto err;
quick_created= TRUE;
}
}
......@@ -18985,7 +19028,37 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
table->sort.found_records=filesort(thd, table,join->sortorder, length,
select, filesort_limit, 0,
&examined_rows);
if (quick_created)
{
/* This will delete the quick select. */
select->cleanup();
}
if (!join->pre_sort_join_tab)
{
if (save_pre_sort_join_tab)
join->pre_sort_join_tab= save_pre_sort_join_tab;
else if (!(join->pre_sort_join_tab= (JOIN_TAB*)thd->alloc(sizeof(JOIN_TAB))))
goto err;
}
*(join->pre_sort_join_tab)= *tab;
if (table->file->inited == handler::INDEX)
{
// Save index #, save index condition
join->pre_sort_index= table->file->active_index;
join->pre_sort_idx_pushed_cond= table->file->pushed_idx_cond;
// no need to save key_read?
err= table->file->ha_index_end();
}
else
join->pre_sort_index= MAX_KEY;
/*TODO: here, close the index scan, cancel index-only read. */
tab->records= table->sort.found_records; // For SQL_CALC_ROWS
#if 0
if (select)
{
/*
......@@ -19002,23 +19075,65 @@ create_sort_index(THD *thd, JOIN *join, ORDER *order,
tablesort_result_cache= table->sort.io_cache;
table->sort.io_cache= NULL;
select->cleanup(); // filesort did select
// select->cleanup(); // filesort did select
table->quick_keys.clear_all(); // as far as we cleanup select->quick
table->intersect_keys.clear_all();
table->sort.io_cache= tablesort_result_cache;
}
#endif
tab->select=NULL;
tab->set_select_cond(NULL, __LINE__);
tab->last_inner= 0;
tab->first_unmatched= 0;
// tab->last_inner= 0;
// tab->first_unmatched= 0;
tab->type=JT_ALL; // Read with normal read_record
tab->read_first_record= join_init_read_record;
tab->table->file->ha_index_or_rnd_end();
if (err)
goto err;
tab->join->examined_rows+=examined_rows;
table->disable_keyread(); // Restore if we used indexes
DBUG_RETURN(table->sort.found_records == HA_POS_ERROR);
err:
DBUG_RETURN(-1);
}
void JOIN::clean_pre_sort_join_tab()
{
TABLE *table= pre_sort_join_tab->table;
/*
Note: we can come here for fake_select_lex object. That object will have
the table already deleted by st_select_lex_unit::cleanup().
We rely on that fake_select_lex didn't have quick select.
*/
#if 0
if (pre_sort_join_tab->select && pre_sort_join_tab->select->quick)
{
/*
We need to preserve tablesort's output resultset here, because
QUICK_INDEX_MERGE_SELECT::~QUICK_INDEX_MERGE_SELECT (called by
SQL_SELECT::cleanup()) may free it assuming it's the result of the quick
select operation that we no longer need. Note that all the other parts of
this data structure are cleaned up when
QUICK_INDEX_MERGE_SELECT::get_next encounters end of data, so the next
SQL_SELECT::cleanup() call changes sort.io_cache alone.
*/
IO_CACHE *tablesort_result_cache;
tablesort_result_cache= table->sort.io_cache;
table->sort.io_cache= NULL;
pre_sort_join_tab->select->cleanup();
table->quick_keys.clear_all(); // as far as we cleanup select->quick
table->intersect_keys.clear_all();
table->sort.io_cache= tablesort_result_cache;
}
#endif
//table->disable_keyread(); // Restore if we used indexes
if (pre_sort_join_tab->select && pre_sort_join_tab->select->quick)
{
pre_sort_join_tab->select->cleanup();
}
}
/*****************************************************************************
Remove duplicates from tmp table
This should be recoded to add a unique index to the table and remove
......@@ -21502,6 +21617,7 @@ int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
tmp4.length(0);
quick_type= -1;
QUICK_SELECT_I *quick= NULL;
JOIN_TAB *saved_join_tab= NULL;
/* Don't show eliminated tables */
if (table->map & join->eliminated_tables)
......@@ -21510,6 +21626,12 @@ int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
continue;
}
if (tab == first_top_tab && pre_sort_join_tab)
{
saved_join_tab= tab;
tab= pre_sort_join_tab;
}
item_list.empty();
/* id */
item_list.push_back(new Item_uint((uint32)select_id));
......@@ -21656,7 +21778,6 @@ int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
keylen_str_buf);
tmp3.append(keylen_str_buf, length, cs);
/*<<<<<<< TREE
}
if ((is_hj || tab->type==JT_RANGE || tab->type == JT_INDEX_MERGE) &&
tab->select && tab->select->quick)
=======*/
......@@ -21977,6 +22098,9 @@ int JOIN::print_explain(select_result_sink *result, uint8 explain_flags,
item_list.push_back(new Item_string(str, len, cs));
}
if (saved_join_tab)
tab= saved_join_tab;
// For next iteration
used_tables|=table->map;
if (result->send_data(item_list))
......
sql/sql_select.h
View file @ ab70b76d
......@@ -903,6 +903,14 @@ protected:
public:
JOIN_TAB *join_tab, **best_ref;
/*
Saved join_tab for pre_sorting. create_sort_index() will save here..
*/
JOIN_TAB *pre_sort_join_tab;
uint pre_sort_index;
Item *pre_sort_idx_pushed_cond;
void clean_pre_sort_join_tab();
/*
For "Using temporary+Using filesort" queries, JOIN::join_tab can point to
......@@ -1293,6 +1301,8 @@ public:
outer_ref_cond= pseudo_bits_cond= NULL;
in_to_exists_where= NULL;
in_to_exists_having= NULL;
pre_sort_join_tab= NULL;
}
int prepare(Item ***rref_pointer_array, TABLE_LIST *tables, uint wind_num,
......
sql/sql_show.cc
View file @ ab70b76d
......@@ -8495,7 +8495,7 @@ ST_FIELD_INFO show_explain_fields_info[]=
SKIP_OPEN_TABLE},
{"table", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0 /*value*/, MY_I_S_MAYBE_NULL,
"table", SKIP_OPEN_TABLE},
{"type", 10, MYSQL_TYPE_STRING, 0, MY_I_S_MAYBE_NULL, "type", SKIP_OPEN_TABLE},
{"type", 11, MYSQL_TYPE_STRING, 0, MY_I_S_MAYBE_NULL, "type", SKIP_OPEN_TABLE},
{"possible_keys", NAME_CHAR_LEN*MAX_KEY, MYSQL_TYPE_STRING, 0/*value*/,
MY_I_S_MAYBE_NULL, "possible_keys", SKIP_OPEN_TABLE},
{"key", NAME_CHAR_LEN, MYSQL_TYPE_STRING, 0/*value*/, MY_I_S_MAYBE_NULL,
......
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