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MDEV-30659 Server crash on EXPLAIN SELECT/SELECT on table with engine Aria for LooseScan Strategy

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Amended patch from Monty:

The issue was that Loose_scan_opt::save_to_position() did not take
into account records_out from best_access_path()

Make sure that POSITION object filled by Loose_scan_opt::save_to_position()
has records_out not higher than any other possible access method.
This commit is contained in:
Sergei Petrunia
2023-02-21 12:04:37 +03:00
parent d5d7c8ba96
commit d61bc94fa0
6 changed files with 175 additions and 6 deletions
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54
mysql-test/main/selectivity.result
View File

@ -2011,3 +2011,57 @@ INSERT INTO t2 VALUES (1),(2);
SELECT STRAIGHT_JOIN pk FROM t1 JOIN t2 ON a = pk WHERE b >= 'A' ORDER BY t2.pk LIMIT 8 OFFSET 1;
pk
DROP TABLE t1, t2;
#
# MDEV-30659 Server crash on EXPLAIN SELECT/SELECT on table with
# engine Aria for LooseScan Strategy
#
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
insert into t1(c1,c2,c3)
values (1,1,1), (1,2,2), (1,3,3),
(2,1,4), (2,2,5), (2,3,6),
(2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and
c2 >= 3 order by c2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a range t1_c2 t1_c2 5 NULL 5 Using where; Using index; LooseScan
1 PRIMARY t1 ref t1_c2 t1_c2 5 test.a.c2 1
drop table t1;
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
create trigger trg_t1 before update on t1 for each row
begin
set new.old_c1=old.c1;
set new.old_c2=old.c2;
end;
/
insert into t1 (c1,c2,c3) values
(1,1,1), (1,2,2), (1,3,3), (2,1,4), (2,2,5), (2,3,6), (2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
analyze table t1 persistent for all;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
create table t2 as select * from t1;
truncate table t1;
insert into t1 select * from t2;
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and c2 >= 3 order by c2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a range t1_c2 t1_c2 5 NULL 5 Using where; Using index; LooseScan
1 PRIMARY t1 ref t1_c2 t1_c2 5 test.a.c2 1
drop trigger trg_t1;
drop table t1,t2;
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
insert into t1 (c1,c2,c3) values
(1,1,1), (1,2,2), (1,3,3), (2,1,4), (2,2,5), (2,3,6), (2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
create table t2 as select * from t1;
truncate table t1;
insert into t1 select * from t2;
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and c2 >= 3 order by c2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a range t1_c2 t1_c2 5 NULL 5 Using where; Using index; LooseScan
1 PRIMARY t1 ref t1_c2 t1_c2 5 test.a.c2 2
drop table t1,t2;

51
mysql-test/main/selectivity.test
View File

@ -1376,3 +1376,54 @@ INSERT INTO t2 VALUES (1),(2);
SELECT STRAIGHT_JOIN pk FROM t1 JOIN t2 ON a = pk WHERE b >= 'A' ORDER BY t2.pk LIMIT 8 OFFSET 1;
DROP TABLE t1, t2;
--echo #
--echo # MDEV-30659 Server crash on EXPLAIN SELECT/SELECT on table with
--echo # engine Aria for LooseScan Strategy
--echo #
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
insert into t1(c1,c2,c3)
values (1,1,1), (1,2,2), (1,3,3),
(2,1,4), (2,2,5), (2,3,6),
(2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and
c2 >= 3 order by c2;
drop table t1;
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
delimiter /;
create trigger trg_t1 before update on t1 for each row
begin
set new.old_c1=old.c1;
set new.old_c2=old.c2;
end;
/
delimiter ;/
insert into t1 (c1,c2,c3) values
(1,1,1), (1,2,2), (1,3,3), (2,1,4), (2,2,5), (2,3,6), (2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
analyze table t1 persistent for all;
create table t2 as select * from t1;
truncate table t1;
insert into t1 select * from t2;
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and c2 >= 3 order by c2;
drop trigger trg_t1;
drop table t1,t2;
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
insert into t1 (c1,c2,c3) values
(1,1,1), (1,2,2), (1,3,3), (2,1,4), (2,2,5), (2,3,6), (2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
create table t2 as select * from t1;
truncate table t1;
insert into t1 select * from t2;
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and c2 >= 3 order by c2;
drop table t1,t2;

54
mysql-test/main/selectivity_innodb.result
View File

@ -2018,6 +2018,60 @@ INSERT INTO t2 VALUES (1),(2);
SELECT STRAIGHT_JOIN pk FROM t1 JOIN t2 ON a = pk WHERE b >= 'A' ORDER BY t2.pk LIMIT 8 OFFSET 1;
pk
DROP TABLE t1, t2;
#
# MDEV-30659 Server crash on EXPLAIN SELECT/SELECT on table with
# engine Aria for LooseScan Strategy
#
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
insert into t1(c1,c2,c3)
values (1,1,1), (1,2,2), (1,3,3),
(2,1,4), (2,2,5), (2,3,6),
(2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and
c2 >= 3 order by c2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a range t1_c2 t1_c2 5 NULL 5 Using where; Using index; LooseScan
1 PRIMARY t1 ref t1_c2 t1_c2 5 test.a.c2 1
drop table t1;
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
create trigger trg_t1 before update on t1 for each row
begin
set new.old_c1=old.c1;
set new.old_c2=old.c2;
end;
/
insert into t1 (c1,c2,c3) values
(1,1,1), (1,2,2), (1,3,3), (2,1,4), (2,2,5), (2,3,6), (2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
analyze table t1 persistent for all;
Table Op Msg_type Msg_text
test.t1 analyze status Engine-independent statistics collected
test.t1 analyze status OK
create table t2 as select * from t1;
truncate table t1;
insert into t1 select * from t2;
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and c2 >= 3 order by c2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a range t1_c2 t1_c2 5 NULL 5 Using where; Using index; LooseScan
1 PRIMARY t1 ref t1_c2 t1_c2 5 test.a.c2 1
drop trigger trg_t1;
drop table t1,t2;
create table t1 (old_c1 integer, old_c2 integer, c1 integer,
c2 integer, c3 integer) engine=aria;
insert into t1 (c1,c2,c3) values
(1,1,1), (1,2,2), (1,3,3), (2,1,4), (2,2,5), (2,3,6), (2,4,7), (2,5,8);
create index t1_c2 on t1 (c2,c1);
create table t2 as select * from t1;
truncate table t1;
insert into t1 select * from t2;
explain select * from t1 where t1.c2 in (select a.c2 from t1 a) and c2 >= 3 order by c2;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY a range t1_c2 t1_c2 5 NULL 5 Using where; Using index; LooseScan
1 PRIMARY t1 ref t1_c2 t1_c2 5 test.a.c2 2
drop table t1,t2;
set optimizer_switch=@save_optimizer_switch_for_selectivity_test;
set @tmp_ust= @@use_stat_tables;
set @tmp_oucs= @@optimizer_use_condition_selectivity;

13
sql/opt_subselect.h
View File

@ -294,14 +294,23 @@ public:
}
}
void save_to_position(JOIN_TAB *tab, double record_count, POSITION *pos)
void save_to_position(JOIN_TAB *tab, double record_count,
double records_out,
POSITION *pos)
{
pos->read_time= best_loose_scan_cost;
if (best_loose_scan_cost != DBL_MAX)
{
/*
Make sure LooseScan plan doesn't produce more rows than
the records_out of other table access method.
*/
set_if_smaller(best_loose_scan_records, records_out);
pos->loops= record_count;
pos->records_read= best_loose_scan_records;
pos->records_init= pos->records_out= pos->records_read;
pos->records_init= pos->records_read;
pos->records_out= best_loose_scan_records;
pos->key= best_loose_scan_start_key;
pos->cond_selectivity= 1.0;
pos->loosescan_picker.loosescan_key= best_loose_scan_key;

8
sql/sql_select.cc
View File

@ -8155,7 +8155,6 @@ best_access_path(JOIN *join,
best.uses_jbuf= FALSE;
best.spl_plan= 0;
pos->loops= record_count;
disable_jbuf= disable_jbuf || idx == join->const_tables;
trace_wrapper.add_table_name(s);
@ -9282,6 +9281,7 @@ best_access_path(JOIN *join,
crash_if_first_double_is_bigger(best.records_out, best.records_read);
/* Update the cost information for the current partial plan */
pos->loops= record_count;
pos->records_init= best.records_read;
pos->records_after_filter= best.records_after_filter;
pos->records_read= best.records;
@ -9299,7 +9299,8 @@ best_access_path(JOIN *join,
pos->key_dependent= (best.type == JT_EQ_REF ? (table_map) 0 :
key_dependent & remaining_tables);
loose_scan_opt.save_to_position(s, record_count, loose_scan_pos);
loose_scan_opt.save_to_position(s, record_count, pos->records_out,
loose_scan_pos);
if (!best.key &&
idx == join->const_tables && // First table
@ -30525,9 +30526,8 @@ static bool get_range_limit_read_cost(const POSITION *pos,
cond_selectivity= best_rows / range_rows;
else
cond_selectivity= 1.0;
#if 0 // FIXME: cond_selectivity=8/4 = 2 in main.update_use_source
DBUG_ASSERT(cond_selectivity <= 1.000000001);
#endif
set_if_smaller(cond_selectivity, 1.0);
/*

1
sql/sql_select.h
View File

@ -1022,6 +1022,7 @@ public:
*/
double read_time;
/* record combinations before this table */
double loops;
double prefix_record_count;