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MDEV-406: ANALYZE $stmt: add support for BNL join buffering

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This commit is contained in:
Sergei Petrunia
2014-06-25 15:15:38 +04:00
parent c3cfb6910a
commit 7711999d8b
8 changed files with 122 additions and 26 deletions
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37
mysql-test/r/analyze_stmt.result
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@ -79,4 +79,41 @@ analyze select a, a in (select t0.b from t0 where t0.b+1=t1.b+1) from t1 where t
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 3 3 100.00 0.00 Using where
2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 10 NULL 100.00 NULL Using where
drop table t0, t1;
#
# Tests for join buffering
#
create table t0 (a int, b int);
insert into t0 values
(0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9);
create table t1 like t0;
insert into t1 select * from t0;
explain select * from t0, t1 where t0.a<5 and t1.a<5;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
# These should have filtered=50
analyze select * from t0, t1 where t0.a<5 and t1.a<5;
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 10 100.00 50.00 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 10 100.00 50.00 Using where; Using join buffer (flat, BNL join)
explain select * from t0, t1 where t0.a<5 and t1.b=t0.b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
# Now, t1 should have filtered=10
analyze select * from t0, t1 where t0.a<5 and t1.b=t0.b;
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 10 100.00 50.00 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 10 100.00 10.00 Using where; Using join buffer (flat, BNL join)
explain select * from t0, t1 where t0.a<5 and t1.a<5 and t1.b=t0.b;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 Using where; Using join buffer (flat, BNL join)
# Now, t1 should have filtered=10
analyze select * from t0, t1 where t0.a<5 and t1.a<5 and t1.b=t0.b;
id select_type table type possible_keys key key_len ref rows r_rows filtered r_filtered Extra
1 SIMPLE t0 ALL NULL NULL NULL NULL 10 10 100.00 50.00 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 10 10 100.00 10.00 Using where; Using join buffer (flat, BNL join)
drop table t0,t1;
# TODO: Check what is counted for "range checked for each record".

25
mysql-test/t/analyze_stmt.test
View File

@ -61,5 +61,30 @@ analyze select a, a in (select t0.b from t0 where t0.b+1=t1.b+1) from t1;
--echo # Try a subquery that is never executed
analyze select a, a in (select t0.b from t0 where t0.b+1=t1.b+1) from t1 where t1.a > 5;
drop table t0, t1;
--echo #
--echo # Tests for join buffering
--echo #
create table t0 (a int, b int);
insert into t0 values
(0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9);
create table t1 like t0;
insert into t1 select * from t0;
explain select * from t0, t1 where t0.a<5 and t1.a<5;
--echo # These should have filtered=50
analyze select * from t0, t1 where t0.a<5 and t1.a<5;
explain select * from t0, t1 where t0.a<5 and t1.b=t0.b;
--echo # Now, t1 should have filtered=10
analyze select * from t0, t1 where t0.a<5 and t1.b=t0.b;
explain select * from t0, t1 where t0.a<5 and t1.a<5 and t1.b=t0.b;
--echo # Now, t1 should have filtered=10
analyze select * from t0, t1 where t0.a<5 and t1.a<5 and t1.b=t0.b;
drop table t0,t1;
--echo # TODO: Check what is counted for "range checked for each record".

10
sql/sql_explain.cc
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@ -585,12 +585,10 @@ int Explain_table_access::print_explain(select_result_sink *output, uint8 explai
}
else
{
double r_filtered;
if (tracker.r_rows > 0)
r_filtered= 100.0 * (double)tracker.r_rows_after_table_cond / tracker.r_rows;
else
r_filtered= 100.0;
item_list.push_back(new Item_float(r_filtered, 2));
double r_filtered= tracker.get_filtered_after_where();
if (bka_type.is_using_jbuf())
r_filtered *= jbuf_tracker.get_filtered_after_where();
item_list.push_back(new Item_float(r_filtered*100.0, 2));
}
}

24
sql/sql_explain.h
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@ -19,13 +19,13 @@ class Table_access_tracker
{
public:
Table_access_tracker() :
r_scans(0), r_rows(0), r_rows_after_table_cond(0),
r_scans(0), r_rows(0), /*r_rows_after_table_cond(0),*/
r_rows_after_where(0)
{}
ha_rows r_scans; /* How many scans were ran on this join_tab */
ha_rows r_rows; /* How many rows we've got after that */
ha_rows r_rows_after_table_cond; /* Rows after applying the table condition */
// ha_rows r_rows_after_table_cond; /* Rows after applying the table condition */
ha_rows r_rows_after_where; /* Rows after applying attached part of WHERE */
bool has_scans() { return (r_scans != 0); }
@ -33,6 +33,17 @@ public:
{
return r_scans ? (ha_rows)rint((double) r_rows / r_scans): 0;
}
double get_filtered_after_where()
{
double r_filtered;
if (r_rows > 0)
r_filtered= (double)r_rows_after_where / r_rows;
else
r_filtered= 1.0;
return r_filtered;
}
};
@ -371,13 +382,17 @@ enum explain_extra_tag
};
typedef struct st_explain_bka_type
class EXPLAIN_BKA_TYPE
{
public:
EXPLAIN_BKA_TYPE() : join_alg(NULL) {}
bool incremental;
const char *join_alg;
StringBuffer<64> mrr_type;
} EXPLAIN_BKA_TYPE;
bool is_using_jbuf() { return (join_alg != NULL); }
};
/*
@ -517,6 +532,7 @@ public:
/* ANALYZE members*/
Table_access_tracker tracker;
Table_access_tracker jbuf_tracker;
private:
void append_tag_name(String *str, enum explain_extra_tag tag);

28
sql/sql_join_cache.cc
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@ -2271,11 +2271,13 @@ enum_nested_loop_state JOIN_CACHE::join_matching_records(bool skip_last)
/* Prepare to read matching candidates from the join buffer */
if (prepare_look_for_matches(skip_last))
continue;
join_tab->jbuf_tracker->r_scans++;
uchar *rec_ptr;
/* Read each possible candidate from the buffer and look for matches */
while ((rec_ptr= get_next_candidate_for_match()))
{
join_tab->jbuf_tracker->r_rows++;
/*
If only the first match is needed, and, it has been already found for
the next record read from the join buffer, then the record is skipped.
@ -2446,6 +2448,8 @@ inline bool JOIN_CACHE::check_match(uchar *rec_ptr)
if (join_tab->select && join_tab->select->skip_record(join->thd) <= 0)
DBUG_RETURN(FALSE);
join_tab->jbuf_tracker->r_rows_after_where++;
if (!join_tab->is_last_inner_table())
DBUG_RETURN(TRUE);
@ -2568,7 +2572,7 @@ finish:
none
*/
void JOIN_CACHE::save_explain_data(struct st_explain_bka_type *explain)
void JOIN_CACHE::save_explain_data(EXPLAIN_BKA_TYPE *explain)
{
explain->incremental= MY_TEST(prev_cache);
@ -2613,14 +2617,14 @@ static void add_mrr_explain_info(String *str, uint mrr_mode, handler *file)
}
}
void JOIN_CACHE_BKA::save_explain_data(struct st_explain_bka_type *explain)
void JOIN_CACHE_BKA::save_explain_data(EXPLAIN_BKA_TYPE *explain)
{
JOIN_CACHE::save_explain_data(explain);
add_mrr_explain_info(&explain->mrr_type, mrr_mode, join_tab->table->file);
}
void JOIN_CACHE_BKAH::save_explain_data(struct st_explain_bka_type *explain)
void JOIN_CACHE_BKAH::save_explain_data(EXPLAIN_BKA_TYPE *explain)
{
JOIN_CACHE::save_explain_data(explain);
add_mrr_explain_info(&explain->mrr_type, mrr_mode, join_tab->table->file);
@ -3326,6 +3330,7 @@ int JOIN_TAB_SCAN::open()
{
save_or_restore_used_tabs(join_tab, FALSE);
is_first_record= TRUE;
join_tab->tracker->r_scans++;
return join_init_read_record(join_tab);
}
@ -3364,8 +3369,14 @@ int JOIN_TAB_SCAN::next()
is_first_record= FALSE;
else
err= info->read_record(info);
if (!err && table->vfield)
if (!err)
{
join_tab->tracker->r_rows++;
if (table->vfield)
update_virtual_fields(thd, table);
}
while (!err && select && (skip_rc= select->skip_record(thd)) <= 0)
{
if (thd->check_killed() || skip_rc < 0)
@ -3375,9 +3386,16 @@ int JOIN_TAB_SCAN::next()
meet the condition pushed to the table join_tab.
*/
err= info->read_record(info);
if (!err && table->vfield)
if (!err)
{
join_tab->tracker->r_rows++;
if (table->vfield)
update_virtual_fields(thd, table);
}
}
if (!err)
join_tab->tracker->r_rows_after_where++;
return err;
}

8
sql/sql_join_cache.h
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@ -63,7 +63,7 @@ typedef struct st_cache_field {
class JOIN_TAB_SCAN;
struct st_explain_bka_type;
class EXPLAIN_BKA_TYPE;
/*
JOIN_CACHE is the base class to support the implementations of
@ -659,7 +659,7 @@ public:
enum_nested_loop_state join_records(bool skip_last);
/* Add a comment on the join algorithm employed by the join cache */
virtual void save_explain_data(struct st_explain_bka_type *explain);
virtual void save_explain_data(EXPLAIN_BKA_TYPE *explain);
THD *thd();
@ -1337,7 +1337,7 @@ public:
/* Check index condition of the joined table for a record from BKA cache */
bool skip_index_tuple(range_id_t range_info);
void save_explain_data(struct st_explain_bka_type *explain);
void save_explain_data(EXPLAIN_BKA_TYPE *explain);
};
@ -1428,5 +1428,5 @@ public:
/* Check index condition of the joined table for a record from BKAH cache */
bool skip_index_tuple(range_id_t range_info);
void save_explain_data(struct st_explain_bka_type *explain);
void save_explain_data(EXPLAIN_BKA_TYPE *explain);
};

3
sql/sql_select.cc
View File

@ -17731,7 +17731,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
There is no select condition or the attached pushed down
condition is true => a match is found.
*/
join_tab->tracker->r_rows_after_table_cond++;
join_tab->tracker->r_rows_after_where++;
bool found= 1;
while (join_tab->first_unmatched && found)
{
@ -23308,6 +23308,7 @@ void JOIN_TAB::save_explain_data(Explain_table_access *eta, table_map prefix_tab
eta->quick_info= NULL;
tab->tracker= &eta->tracker;
tab->jbuf_tracker= &eta->jbuf_tracker;
/* id */
if (tab->bush_root_tab)

1
sql/sql_select.h
View File

@ -252,6 +252,7 @@ typedef struct st_join_table {
enum explain_extra_tag info;
Table_access_tracker *tracker;
Table_access_tracker *jbuf_tracker;
/*
Bitmap of TAB_INFO_* bits that encodes special line for EXPLAIN 'Extra'
column, or 0 if there is no info.