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MDEV-6879: Dereference of NULL primary_file->table in DsMrr_impl::get_disk_sweep_mrr_cost()

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(Attempt #2)
- Don't attempt to use BKA for materialized derived tables. The 
  table is neither filled nor fully opened yet, so attempt to 
  call handler->multi_range_read_info() causes crash.
This commit is contained in:
Sergey Petrunya
2014-10-20 23:35:34 +04:00
parent 8925b4a935
commit 1a996bde1e
3 changed files with 72 additions and 1 deletions
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29
mysql-test/r/derived_opt.result
View File

@ -352,4 +352,33 @@ pk pk
72 72
80 80
drop table t1, t2, t3, t4;
#
# MDEV-6879: Dereference of NULL primary_file->table in DsMrr_impl::get_disk_sweep_mrr_cost()
#
create table t1(a int);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2 (a int, b int, c text);
insert into t2
select
A.a + B.a* 10,
A.a + B.a* 10,
'blob-data'
from t1 A, t1 B;
set @tmp_jcl= @@join_cache_level;
set @tmp_os= @@optimizer_switch;
set join_cache_level=6;
set @@optimizer_switch='derived_merge=on,derived_with_keys=on,mrr=on';
explain
select * from
t1 join
(select * from t2 order by a limit 1000) as D1
where
D1.a= t1.a;
id select_type table type possible_keys key key_len ref rows Extra
1 PRIMARY t1 ALL NULL NULL NULL NULL 10 Using where
1 PRIMARY <derived2> hash_ALL key0 #hash#key0 5 test.t1.a 100 Using join buffer (flat, BNLH join)
2 DERIVED t2 ALL NULL NULL NULL NULL 100 Using filesort
set join_cache_level=@tmp_jcl;
set optimizer_switch=@tmp_os;
drop table t1, t2;
set optimizer_switch=@exit_optimizer_switch;

29
mysql-test/t/derived_opt.test
View File

@ -272,5 +272,34 @@ limit 10;
drop table t1, t2, t3, t4;
--echo #
--echo # MDEV-6879: Dereference of NULL primary_file->table in DsMrr_impl::get_disk_sweep_mrr_cost()
--echo #
create table t1(a int);
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2 (a int, b int, c text);
insert into t2
select
A.a + B.a* 10,
A.a + B.a* 10,
'blob-data'
from t1 A, t1 B;
set @tmp_jcl= @@join_cache_level;
set @tmp_os= @@optimizer_switch;
set join_cache_level=6;
set @@optimizer_switch='derived_merge=on,derived_with_keys=on,mrr=on';
explain
select * from
t1 join
(select * from t2 order by a limit 1000) as D1
where
D1.a= t1.a;
set join_cache_level=@tmp_jcl;
set optimizer_switch=@tmp_os;
drop table t1, t2;
# The following command must be the last one the file
set optimizer_switch=@exit_optimizer_switch;

15
sql/sql_select.cc
View File

@ -10549,6 +10549,19 @@ uint check_join_cache_usage(JOIN_TAB *tab,
cache_level--;
}
/*
Don't use BKA for materialized tables. We could actually have a
meaningful use of BKA when linked join buffers are used.
The problem is, the temp.table is not filled (actually not even opened
properly) yet, and this doesn't let us call
handler->multi_range_read_info(). It is possible to come up with
estimates, etc. without acessing the table, but it seems not to worth the
effort now.
*/
if (tab->table->pos_in_table_list->is_materialized_derived())
no_bka_cache= true;
/*
Don't use join buffering if we're dictated not to by no_jbuf_after
(This is not meaningfully used currently)
@ -10615,7 +10628,7 @@ uint check_join_cache_usage(JOIN_TAB *tab,
if (tab->ref.is_access_triggered())
goto no_join_cache;
if (!tab->is_ref_for_hash_join())
if (!tab->is_ref_for_hash_join() && !no_bka_cache)
{
flags= HA_MRR_NO_NULL_ENDPOINTS | HA_MRR_SINGLE_POINT;
if (tab->table->covering_keys.is_set(tab->ref.key))