DROP TABLE IF EXISTS t1,t2,t3,t4;
DROP DATABASE IF EXISTS dbt3_s001;
SET SESSION STORAGE_ENGINE='InnoDB';
CREATE DATABASE dbt3_s001;
use dbt3_s001;
set @save_ext_key_optimizer_switch=@@optimizer_switch;
set optimizer_switch='extended_keys=off';
explain
select count(*) from lineitem where l_orderkey=130 and l_shipdate='1992-07-01';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	ref	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	PRIMARY	4	const	5	Using where
flush status;
select count(*) from lineitem where l_orderkey=130 and l_shipdate='1992-07-01';
count(*)
1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	5
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select count(*) from lineitem where l_orderkey=130 and l_shipdate='1992-07-01';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	ref	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate	8	const,const	1	Using index
flush status;
select count(*) from lineitem where l_orderkey=130 and l_shipdate='1992-07-01';
count(*)
1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	1
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select count(*) from lineitem 
where l_orderkey=130 and l_linenumber=2 and l_shipdate='1992-07-01';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	const	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	PRIMARY	8	const,const	1	
flush status;
select count(*) from lineitem 
where l_orderkey=130 and l_linenumber=2 and l_shipdate='1992-07-01';
count(*)
1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select count(*) from lineitem
where l_orderkey=130 and l_linenumber=2 and l_shipdate='1992-07-01';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	const	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	PRIMARY	8	const,const	1	
flush status;
select count(*) from lineitem 
where l_orderkey=130 and l_linenumber=2 and l_shipdate='1992-07-01';
count(*)
1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain 
select count(*) from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	ref	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate	4	const	6	Using where; Using index
flush status;
select count(*) from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000;
count(*)
1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	6
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain 
select count(*) from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	range	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate	8	NULL	1	Using where; Using index
flush status;
select count(*) from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000;
count(*)
1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	1
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select l_orderkey, l_linenumber from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	ref	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate	4	const	6	Using where; Using index
flush status;
select l_orderkey, l_linenumber from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
l_orderkey	l_linenumber
1088	3
1217	1
1221	3
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	6
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select l_orderkey, l_linenumber from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	range	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate	8	NULL	3	Using where; Using index
flush status;
select l_orderkey, l_linenumber from lineitem
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
l_orderkey	l_linenumber
1088	3
1217	1
1221	3
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	3
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select min(l_orderkey) from lineitem where l_shipdate='1992-07-01';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	ref	i_l_shipdate	i_l_shipdate	4	const	6	Using index
flush status;
select min(l_orderkey) from lineitem where l_shipdate='1992-07-01';
min(l_orderkey)
130
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	6
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select min(l_orderkey) from lineitem where l_shipdate='1992-07-01';
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
flush status;
select min(l_orderkey) from lineitem where l_shipdate='1992-07-01';
min(l_orderkey)
130
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select min(l_orderkey) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	ref	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate	4	const	6	Using where; Using index
flush status;
select min(l_orderkey) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
min(l_orderkey)
1088
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	6
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select min(l_orderkey) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
flush status;
select min(l_orderkey) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1001 and 2000;
min(l_orderkey)
1088
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select max(l_linenumber) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey=130;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	ref	PRIMARY,i_l_shipdate,i_l_orderkey,i_l_orderkey_quantity	PRIMARY	4	const	5	Using where
flush status;
select max(l_linenumber) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey=130;
max(l_linenumber)
2
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	5
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select max(l_linenumber) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey=130;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	NULL	NULL	NULL	NULL	NULL	NULL	NULL	Select tables optimized away
flush status;
select max(l_linenumber) from lineitem 
where l_shipdate='1992-07-01' and l_orderkey=130;
max(l_linenumber)
2
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select l_orderkey, l_linenumber 
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey=130 
or l_receiptdate='1992-07-01' and l_orderkey=5603;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	index_merge	i_l_shipdate,i_l_receiptdate	i_l_shipdate,i_l_receiptdate	4,4	NULL	9	Using union(i_l_shipdate,i_l_receiptdate); Using where
flush status;
select l_orderkey, l_linenumber 
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey=130 
or l_receiptdate='1992-07-01' and l_orderkey=5603;
l_orderkey	l_linenumber
130	2
5603	2
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	2
Handler_read_last	0
Handler_read_next	9
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	9
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select l_orderkey, l_linenumber 
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey=130 
or l_receiptdate='1992-07-01' and l_orderkey=5603;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	index_merge	i_l_shipdate,i_l_receiptdate	i_l_shipdate,i_l_receiptdate	8,8	NULL	2	Using union(i_l_shipdate,i_l_receiptdate); Using where
flush status;
select l_orderkey, l_linenumber 
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey=130 
or l_receiptdate='1992-07-01' and l_orderkey=5603;
l_orderkey	l_linenumber
130	2
5603	2
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	2
Handler_read_last	0
Handler_read_next	2
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	2
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select l_orderkey, l_linenumber
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	index_merge	i_l_shipdate,i_l_receiptdate	i_l_shipdate,i_l_receiptdate	4,4	NULL	9	Using union(i_l_shipdate,i_l_receiptdate); Using where
flush status;
select l_orderkey, l_linenumber
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
l_orderkey	l_linenumber
130	2
5603	2
5959	3
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	2
Handler_read_last	0
Handler_read_next	9
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	9
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select l_orderkey, l_linenumber
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	index_merge	i_l_shipdate,i_l_receiptdate	i_l_shipdate,i_l_receiptdate	8,8	NULL	3	Using sort_union(i_l_shipdate,i_l_receiptdate); Using where
flush status;
select l_orderkey, l_linenumber
from lineitem use index (i_l_shipdate, i_l_receiptdate)
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
l_orderkey	l_linenumber
130	2
5603	2
5959	3
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	2
Handler_read_last	0
Handler_read_next	3
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	3
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain
select l_orderkey, l_linenumber from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	index_merge	PRIMARY,i_l_shipdate,i_l_receiptdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate,PRIMARY,i_l_receiptdate,PRIMARY	4,4,4,4	NULL	2	Using union(intersect(i_l_shipdate,PRIMARY),intersect(i_l_receiptdate,PRIMARY)); Using where
flush status;
select l_orderkey, l_linenumber from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
l_orderkey	l_linenumber
130	2
5603	2
5959	3
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	2
Handler_read_last	0
Handler_read_next	9
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	3
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select l_orderkey, l_linenumber from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	index_merge	PRIMARY,i_l_shipdate,i_l_receiptdate,i_l_orderkey,i_l_orderkey_quantity	i_l_shipdate,i_l_receiptdate	8,8	NULL	3	Using sort_union(i_l_shipdate,i_l_receiptdate); Using where
flush status;
select l_orderkey, l_linenumber from lineitem 
where l_shipdate='1992-07-01' and l_orderkey between 1 and 1000
or l_receiptdate='1992-07-01' and l_orderkey between 5001 and 6000;
l_orderkey	l_linenumber
130	2
5603	2
5959	3
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	2
Handler_read_last	0
Handler_read_next	3
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	3
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain 
select max(l_orderkey) from lineitem
where l_partkey between 1 and 10 group by l_partkey;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	range	i_l_suppkey_partkey,i_l_partkey	i_l_partkey	5	NULL	#	Using where; Using index
flush status;
select max(l_orderkey) from lineitem
where l_partkey between 1 and 10 group by l_partkey;
max(l_orderkey)
5984
5957
5892
5856
5959
5957
5794
5894
5859
5632
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	1
Handler_read_last	0
Handler_read_next	294
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain 
select max(l_orderkey) from lineitem
where l_partkey between 1 and 10 group by l_partkey;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	range	i_l_suppkey_partkey,i_l_partkey	i_l_partkey	5	NULL	#	Using where; Using index for group-by
flush status;
select max(l_orderkey) from lineitem
where l_partkey between 1 and 10 group by l_partkey;
max(l_orderkey)
5984
5957
5892
5856
5959
5957
5794
5894
5859
5632
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	21
Handler_read_last	1
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=off';
explain 
select max(l_orderkey) from lineitem
where l_suppkey in (1,4) group by l_suppkey;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	range	i_l_suppkey	i_l_suppkey	5	NULL	#	Using where; Using index
flush status;
select max(l_orderkey) from lineitem
where l_suppkey in (1,4) group by l_suppkey;
max(l_orderkey)
5988
5984
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	2
Handler_read_last	0
Handler_read_next	1230
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain 
select max(l_orderkey) from lineitem
where l_suppkey in (1,4) group by l_suppkey;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	lineitem	range	i_l_suppkey	i_l_suppkey	5	NULL	#	Using where; Using index for group-by
flush status;
select max(l_orderkey) from lineitem
where l_suppkey in (1,4) group by l_suppkey;
max(l_orderkey)
5988
5984
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	6
Handler_read_last	1
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
create index i_p_retailprice on part(p_retailprice);
set optimizer_switch='extended_keys=off';
explain
select o_orderkey, p_partkey
from part use index (i_p_retailprice),
lineitem use index (i_l_partkey), orders
where p_retailprice > 1100 and o_orderdate='1997-01-01' 
and o_orderkey=l_orderkey and p_partkey=l_partkey;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	part	range	i_p_retailprice	i_p_retailprice	9	NULL	#	Using where; Using index
1	SIMPLE	orders	ref	PRIMARY,i_o_orderdate	i_o_orderdate	4	const	#	Using index
1	SIMPLE	lineitem	ref	i_l_partkey	i_l_partkey	5	dbt3_s001.part.p_partkey	#	Using where; Using index
flush status;
select o_orderkey, p_partkey
from part use index (i_p_retailprice),
lineitem use index (i_l_partkey), orders
where p_retailprice > 1100 and o_orderdate='1997-01-01' 
and o_orderkey=l_orderkey and p_partkey=l_partkey;
o_orderkey	p_partkey
5895	200
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	3
Handler_read_last	0
Handler_read_next	26
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
set optimizer_switch='extended_keys=on';
explain
select o_orderkey, p_partkey
from part use index (i_p_retailprice),
lineitem use index (i_l_partkey), orders
where p_retailprice > 1100 and o_orderdate='1997-01-01' 
and o_orderkey=l_orderkey and p_partkey=l_partkey;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	part	range	i_p_retailprice	i_p_retailprice	9	NULL	#	Using where; Using index
1	SIMPLE	orders	ref	PRIMARY,i_o_orderdate	i_o_orderdate	4	const	#	Using index
1	SIMPLE	lineitem	ref	i_l_partkey	i_l_partkey	9	dbt3_s001.part.p_partkey,dbt3_s001.orders.o_orderkey	#	Using index
flush status;
select o_orderkey, p_partkey
from part use index (i_p_retailprice),
lineitem use index (i_l_partkey), orders
where p_retailprice > 1100 and o_orderdate='1997-01-01' 
and o_orderkey=l_orderkey and p_partkey=l_partkey;
o_orderkey	p_partkey
5895	200
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	3
Handler_read_last	0
Handler_read_next	3
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	0
#
# Bug mdev-3851: ref access used instead of expected eq_ref access
#                when extended_keys=on
#
create table t0 (a int);
insert into t0 values (1), (2), (3), (4), (5);
create index i_p_size on part(p_size);
set optimizer_switch='extended_keys=on';
explain
select * from t0, part ignore index (primary)
where p_partkey=t0.a and p_size=1;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t0	ALL	NULL	NULL	NULL	NULL	5	Using where
1	SIMPLE	part	eq_ref	i_p_size	i_p_size	9	const,dbt3_s001.t0.a	1	
select * from t0,  part ignore index (primary)
where p_partkey=t0.a and p_size=1;
a	p_partkey	p_name	p_mfgr	p_brand	p_type	p_size	p_container	p_retailprice	p_comment
2	2	blush rosy metallic lemon navajo	Manufacturer#1	Brand#13	LARGE BRUSHED BRASS	1	LG CASE	902	final platelets hang f
drop table t0;
drop index i_p_size on part;
DROP DATABASE dbt3_s001;
use test;
#
# LP Bug #914560: query containing IN subquery
#                 + extended_keys = on
#
set @save_optimizer_switch=@@optimizer_switch;
SET optimizer_switch='materialization=on,semijoin=on';
SET optimizer_switch='extended_keys=on';
CREATE TABLE t1 (a int, b int) ENGINE=MyISAM;
INSERT INTO t1 VALUES (1,1), (2,2);
SELECT * FROM t1 WHERE 2 IN (SELECT MAX(s1.a) FROM t1 AS s1, t1 AS s2);
a	b
1	1
2	2
EXPLAIN
SELECT * FROM t1 WHERE 2 IN (SELECT MAX(s1.a) FROM t1 AS s1, t1 AS s2);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	<subquery2>	const	distinct_key	distinct_key	4	const	1	
1	PRIMARY	t1	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (flat, BNL join)
2	MATERIALIZED	s1	ALL	NULL	NULL	NULL	NULL	2	
2	MATERIALIZED	s2	ALL	NULL	NULL	NULL	NULL	2	Using join buffer (flat, BNL join)
DROP TABLE t1;
set optimizer_switch=@save_optimizer_switch;
#
# LP Bug #915291: query using a materialized view
#                 + extended_keys = on
# (valgrinf complains fixed by the patch for bug #914560)
#
set @save_optimizer_switch=@@optimizer_switch;
SET optimizer_switch = 'derived_with_keys=on';
SET optimizer_switch = 'extended_keys=on';
CREATE TABLE t1 (a varchar(1)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('j'), ('v');
CREATE TABLE t2 (b varchar(1)) ENGINE=MyISAM;
INSERT INTO t2 VALUES ('j'), ('v');
CREATE TABLE t3 (c varchar(1));
INSERT INTO t2 VALUES ('m'), ('n');
CREATE VIEW v
AS SELECT DISTINCT * FROM t2 STRAIGHT_JOIN t3;
SELECT * FROM t1, v WHERE a = b;
a	b	c
DROP VIEW v;
DROP TABLE t1,t2,t3;
set optimizer_switch=@save_optimizer_switch;
#
# LP Bug #921167: query containing IN subquery
#                 + extended_keys = on 
#
CREATE TABLE t1 (
a int NOT NULL, b varchar(1) NOT NULL, KEY(a), KEY(b,a)
) ENGINE=MyISAM;
INSERT INTO t1 VALUES
(0,'j'), (8,'v'), (1,'c'), (8,'m'), (9,'d'), 
(24,'d'), (6,'y'), (1,'t'), (6,'d'), (2,'s');
CREATE TABLE t2 (
c int NOT NULL PRIMARY KEY
) ENGINE=MyISAM;
INSERT INTO t2 VALUES
(10), (11), (12), (13), (14), 
(15), (16), (17), (18), (19), (24);
set @save_optimizer_switch=@@optimizer_switch;
SET optimizer_switch = 'extended_keys=off';
EXPLAIN
SELECT a FROM t1 AS t, t2 
WHERE c = a AND b IN (SELECT b FROM t1, t2 WHERE b = t.b);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t	index	a,b	b	7	NULL	10	Using index
1	PRIMARY	t1	ref	b	b	3	test.t.b	2	Using index
1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	11	Using index; FirstMatch(t)
1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t.a	1	Using index
SELECT a FROM t1 AS t, t2 
WHERE c = a AND b IN (SELECT b FROM t1, t2 WHERE b = t.b);
a
24
SET optimizer_switch = 'extended_keys=on';
EXPLAIN
SELECT a FROM t1 AS t, t2 
WHERE c = a AND b IN (SELECT b FROM t1, t2 WHERE b = t.b);
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	PRIMARY	t	index	a,b	b	7	NULL	10	Using index
1	PRIMARY	t1	ref	b	b	3	test.t.b	2	Using index
1	PRIMARY	t2	index	NULL	PRIMARY	4	NULL	11	Using index; FirstMatch(t)
1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t.a	1	Using index
SELECT a FROM t1 AS t, t2 
WHERE c = a AND b IN (SELECT b FROM t1, t2 WHERE b = t.b);
a
24
set optimizer_switch=@save_optimizer_switch;
DROP TABLE t1,t2;
#
# LP Bug #923236: hash join + extended_keys = on 
#
CREATE TABLE t1 (a int) ENGINE=MyISAM;
CREATE TABLE t2 (b int) ENGINE=MyISAM;
INSERT INTO t1 (a) VALUES (4), (6);
INSERT INTO t2 (b) VALUES (0), (8);
set @save_optimizer_switch=@@optimizer_switch;
set @save_join_cache_level=@@join_cache_level;
SET join_cache_level=3;
SET optimizer_switch='join_cache_hashed=on';
SET optimizer_switch='join_cache_bka=on';
SET optimizer_switch='extended_keys=on';
EXPLAIN
SELECT * FROM t1, t2 WHERE b=a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	2	Using where
1	SIMPLE	t2	hash_ALL	NULL	#hash#$hj	5	test.t1.a	2	Using where; Using join buffer (flat, BNLH join)
SELECT * FROM t1, t2 WHERE b=a;
a	b
set join_cache_level=@save_join_cache_level;
set optimizer_switch=@save_optimizer_switch;
DROP TABLE t1,t2;
#
# Bug mdev-3888: INSERT with UPDATE on duplicate keys
#                with extended_keys=on   
#
CREATE TABLE t1 (
c1 bigint(20) unsigned NOT NULL AUTO_INCREMENT,
c2 bigint(20) unsigned NOT NULL,
c3 bigint(20) unsigned NOT NULL,
c4 varchar(128) DEFAULT NULL,
PRIMARY KEY (c1),
UNIQUE KEY uq (c2,c3),
KEY c3 (c3),
KEY c4 (c4)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=utf8;
set @save_optimizer_switch=@@optimizer_switch;
set session optimizer_switch='extended_keys=off';
INSERT INTO t1 (c2, c3, c4) VALUES (58291525, 2580, 'foobar')
ON DUPLICATE KEY UPDATE c4 = VALUES(c4);
INSERT INTO t1 (c2, c3, c4) VALUES (58291525, 2580, 'foobar')
ON DUPLICATE KEY UPDATE c4 = VALUES(c4);
DELETE FROM t1;
set session optimizer_switch='extended_keys=on';
INSERT INTO t1 (c2, c3, c4) VALUES (58291525, 2580, 'foobar')
ON DUPLICATE KEY UPDATE c4 = VALUES(c4);
INSERT INTO t1 (c2, c3, c4) VALUES (58291525, 2580, 'foobar')
ON DUPLICATE KEY UPDATE c4 = VALUES(c4);
set optimizer_switch=@save_optimizer_switch;
DROP TABLE t1;
#
# Bug mdev-4220: using ref instead of eq_ref
#                with extended_keys=on   
# (performance regression introduced in the patch for mdev-3851)
#
set @save_optimizer_switch=@@optimizer_switch;
create table t1 (a int not null) engine=innodb;
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2 (
pk int primary key, a int not null, b int, unique(a)
)engine=innodb;
insert into t2
select 
A.a + 10 * B.a, A.a + 10 * B.a, A.a + 10 * B.a 
from t1 A, t1 B;
set optimizer_switch='extended_keys=off';
explain 
select * from t1, t2 where t2.a=t1.a and t2.b < 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	
1	SIMPLE	t2	eq_ref	a	a	4	test.t1.a	1	Using where
flush status;
select * from t1, t2 where t2.a=t1.a and t2.b < 2;
a	pk	a	b
0	0	0	0
1	1	1	1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	10
Handler_read_last	0
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	11
set optimizer_switch='extended_keys=on';
explain 
select * from t1, t2 where t2.a=t1.a and t2.b < 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	10	
1	SIMPLE	t2	eq_ref	a	a	4	test.t1.a	1	Using where
flush status;
select * from t1, t2 where t2.a=t1.a and t2.b < 2;
a	pk	a	b
0	0	0	0
1	1	1	1
show status like 'handler_read%';
Variable_name	Value
Handler_read_first	0
Handler_read_key	10
Handler_read_last	0
Handler_read_next	0
Handler_read_prev	0
Handler_read_retry	0
Handler_read_rnd	0
Handler_read_rnd_deleted	0
Handler_read_rnd_next	11
drop table t1,t2;
create table t1(a int) engine=myisam;
insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);
create table t2(a int) engine=myisam;
insert into t2 select A.a + 10*B.a + 100*C.a from t1 A, t1 B, t1 C;
create table t3 (
pk1 int not null, pk2 int not null, col1 int not null, col2 int not null)
engine=innodb;
insert into t3 select a,a,a,a from t2;
alter table t3 add primary key (pk1, pk2);
alter table t3 add  key (col1, col2);
analyze table t1,t3;
Table	Op	Msg_type	Msg_text
test.t1	analyze	status	OK
test.t3	analyze	status	OK
set optimizer_switch='extended_keys=off';
explain 
select * from t1, t3 where t3.col1=t1.a and  t3.col2=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	#	Using where
1	SIMPLE	t3	ref	col1	col1	8	test.t1.a,test.t1.a	#	Using index
explain 
select * from t1, t3 where t3.col1=t1.a and  t3.col2=t1.a and t3.pk1=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	#	Using where
1	SIMPLE	t3	ref	PRIMARY,col1	col1	8	test.t1.a,test.t1.a	#	Using where; Using index
set optimizer_switch='extended_keys=on';
explain 
select * from t1, t3 where t3.col1=t1.a and  t3.col2=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	#	Using where
1	SIMPLE	t3	ref	col1	col1	8	test.t1.a,test.t1.a	#	Using index
explain 
select * from t1, t3 where t3.col1=t1.a and  t3.col2=t1.a and t3.pk1=t1.a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	#	Using where
1	SIMPLE	t3	ref	PRIMARY,col1	col1	12	test.t1.a,test.t1.a,test.t1.a	#	Using index
drop table t1,t2,t3;
#
# Bug mdev-4340: performance regression with extended_keys=on   
#
set @save_optimizer_switch=@@optimizer_switch;
CREATE TABLE t1 (
page_id int(8) unsigned NOT NULL AUTO_INCREMENT,
page_namespace int(11) NOT NULL DEFAULT '0',
page_title varbinary(255) NOT NULL DEFAULT '',
page_restrictions tinyblob NOT NULL,
page_counter bigint(20) unsigned NOT NULL DEFAULT '0',
page_is_redirect tinyint(1) unsigned NOT NULL DEFAULT '0',
page_is_new tinyint(1) unsigned NOT NULL DEFAULT '0',
page_random double unsigned NOT NULL DEFAULT '0',
page_touched varbinary(14) NOT NULL DEFAULT '',
page_latest int(8) unsigned NOT NULL DEFAULT '0',
page_len int(8) unsigned NOT NULL DEFAULT '0',
PRIMARY KEY (page_id),
UNIQUE KEY name_title (page_namespace,page_title),
KEY page_random (page_random),
KEY page_len (page_len),
KEY page_redirect_namespace_len (page_is_redirect,page_namespace,page_len)
) ENGINE=InnoDB AUTO_INCREMENT=38929100 DEFAULT CHARSET=binary;
INSERT INTO t1 VALUES
(38928077,0,'Sandbox','',0,0,0,0,'',0,0),(38928078,1,'Sandbox','',0,0,0,1,'',0,0),
(38928079,2,'Sandbox','',0,0,0,2,'',0,0),(38928080,3,'Sandbox','',0,0,0,3,'',0,0),
(38928081,4,'Sandbox','',0,0,0,4,'',0,0),(38928082,5,'Sandbox','',0,0,0,5,'',0,0);
CREATE TABLE t2 (
rev_id int(8) unsigned NOT NULL AUTO_INCREMENT,
rev_page int(8) unsigned NOT NULL DEFAULT '0',
rev_text_id int(8) unsigned NOT NULL DEFAULT '0',
rev_comment varbinary(255) DEFAULT NULL,
rev_user int(5) unsigned NOT NULL DEFAULT '0',
rev_user_text varbinary(255) NOT NULL DEFAULT '',
rev_timestamp varbinary(14) NOT NULL DEFAULT '',
rev_minor_edit tinyint(1) unsigned NOT NULL DEFAULT '0',
rev_deleted tinyint(1) unsigned NOT NULL DEFAULT '0',
rev_len int(8) unsigned DEFAULT NULL,
rev_parent_id int(8) unsigned DEFAULT NULL,
rev_sha1 varbinary(32) NOT NULL DEFAULT '',
PRIMARY KEY (rev_page,rev_id),
UNIQUE KEY rev_id (rev_id),
KEY rev_timestamp (rev_timestamp),
KEY page_timestamp (rev_page,rev_timestamp),
KEY user_timestamp (rev_user,rev_timestamp),
KEY usertext_timestamp (rev_user_text,rev_timestamp,rev_user,rev_deleted,rev_minor_edit,rev_text_id,rev_comment)
) ENGINE=InnoDB DEFAULT CHARSET=binary;
INSERT INTO t2 VALUES
(547116222,20,0,NULL,3,'','',0,0,NULL,NULL,''),(547117245,20,0,NULL,4,'','',0,0,NULL,NULL,''),
(547118268,20,0,NULL,5,'','',0,0,NULL,NULL,''),(547114177,21,0,NULL,1,'','',0,0,NULL,NULL,''),
(547115200,21,0,NULL,2,'','',0,0,NULL,NULL,''),(547116223,21,0,NULL,3,'','',0,0,NULL,NULL,''),
(547117246,21,0,NULL,4,'','',0,0,NULL,NULL,''),(547118269,21,0,NULL,5,'','',0,0,NULL,NULL,''),
(547114178,22,0,NULL,1,'','',0,0,NULL,NULL,''),(547115201,22,0,NULL,2,'','',0,0,NULL,NULL,''),
(547116224,22,0,NULL,3,'','',0,0,NULL,NULL,''),(547117247,22,0,NULL,4,'','',0,0,NULL,NULL,''),
(547116226,24,0,NULL,3,'','',0,0,NULL,NULL,''),(547117249,24,0,NULL,4,'','',0,0,NULL,NULL,''),
(547118272,24,0,NULL,5,'','',0,0,NULL,NULL,''),(547114181,25,0,NULL,1,'','',0,0,NULL,NULL,''),
(547115204,25,0,NULL,2,'','',0,0,NULL,NULL,''),(547116227,25,0,NULL,3,'','',0,0,NULL,NULL,''),
(547116157,978,0,NULL,2,'','',0,0,NULL,NULL,''),(547117180,978,0,NULL,3,'','',0,0,NULL,NULL,''),
(547118203,978,0,NULL,4,'','',0,0,NULL,NULL,''),(547119226,978,0,NULL,5,'','',0,0,NULL,NULL,''),
(547115135,979,0,NULL,1,'','',0,0,NULL,NULL,''),(547116158,979,0,NULL,2,'','',0,0,NULL,NULL,''),
(547116173,994,0,NULL,2,'','',0,0,NULL,NULL,''),(547117196,994,0,NULL,3,'','',0,0,NULL,NULL,''),
(547118219,994,0,NULL,4,'','',0,0,NULL,NULL,''),(547119242,994,0,NULL,5,'','',0,0,NULL,NULL,''),
(547115151,995,0,NULL,1,'','',0,0,NULL,NULL,''),(547116174,995,0,NULL,2,'','',0,0,NULL,NULL,''),
(547117197,995,0,NULL,3,'','',0,0,NULL,NULL,''),(547118220,995,0,NULL,4,'','',0,0,NULL,NULL,''),
(547118223,998,0,NULL,4,'','',0,0,NULL,NULL,''),(547119246,998,0,NULL,5,'','',0,0,NULL,NULL,''),
(547115155,999,0,NULL,1,'','',0,0,NULL,NULL,''),(547116178,999,0,NULL,2,'','',0,0,NULL,NULL,''),
(547117201,999,0,NULL,3,'','',0,0,NULL,NULL,''),(547118224,999,0,NULL,4,'','',0,0,NULL,NULL,''),
(547119271,38928081,0,NULL,10,'','',0,0,NULL,NULL,''),(547119272,38928081,0,NULL,11,'','',0,0,NULL,NULL,''),
(547119273,38928081,0,NULL,12,'','',0,0,NULL,NULL,''),(547119274,38928081,0,NULL,13,'','',0,0,NULL,NULL,''),
(547119275,38928081,0,NULL,14,'','',0,0,NULL,NULL,''),(547119276,38928081,0,NULL,15,'','',0,0,NULL,NULL,''),
(547119277,38928081,0,NULL,16,'','',0,0,NULL,NULL,''),(547119278,38928081,0,NULL,17,'','',0,0,NULL,NULL,''),
(547119279,38928081,0,NULL,18,'','',0,0,NULL,NULL,''),(547119280,38928081,0,NULL,19,'','',0,0,NULL,NULL,'');
CREATE TABLE t3 (
old_id int(10) unsigned NOT NULL AUTO_INCREMENT,
old_text mediumblob NOT NULL,
old_flags tinyblob NOT NULL,
PRIMARY KEY (old_id)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
INSERT INTO t3 VALUES
(1,'text-0',''),(2,'text-1000',''),(3,'text-2000',''),(4,'text-3000',''),
(5,'text-4000',''),(6,'text-5000',''),(7,'text-6000',''),(8,'text-7000',''),
(9,'text-8000',''),(10,'text-9000',''),(11,'text-1',''),(12,'text-1001',''),
(13,'text-2001',''),(14,'text-3001',''),(15,'text-4001',''),(16,'text-5001',''),
(17,'text-6001',''),(18,'text-7001',''),(19,'text-8001',''),(20,'text-9001',''),
(21,'text-2',''),(22,'text-1002',''),(23,'text-2002',''),(24,'text-3002',''),
(25,'text-4002',''),(26,'text-5002',''),(27,'text-6002',''),(28,'text-7002',''),
(29,'text-8002',''),(30,'text-9002',''),(31,'text-3',''),(32,'text-1003',''),
(33,'text-2003',''),(34,'text-3003',''),(35,'text-4003',''),(36,'text-5003',''),
(37,'text-6003',''),(38,'text-7003',''),(39,'text-8003',''),(40,'text-9003',''),
(41,'text-4',''),(42,'text-1004',''),(43,'text-2004',''),(44,'text-3004',''),
(45,'text-4004',''),(46,'text-5004',''),(47,'text-6004',''),(48,'text-7004',''),
(49,'text-8004',''),(50,'text-9004',''),(51,'text-5',''),(52,'text-1005',''),
(53,'text-2005',''),(54,'text-3005',''),(55,'text-4005',''),(56,'text-5005',''),
(57,'text-6005',''),(58,'text-7005',''),(59,'text-8005',''),(60,'text-9005',''),
(61,'text-6',''),(62,'text-1006',''),(63,'text-2006',''),(64,'text-3006',''),
(65,'text-4006',''),(66,'text-5006',''),(67,'text-6006',''),(68,'text-7006',''),
(69,'text-8006',''),(70,'text-9006',''),(71,'text-7',''),(72,'text-1007',''),
(73,'text-2007',''),(74,'text-3007',''),(75,'text-4007',''),(76,'text-5007',''),
(77,'text-6007',''),(78,'text-7007',''),(79,'text-8007',''),(80,'text-9007',''),
(81,'text-8',''),(82,'text-1008',''),(83,'text-2008',''),(84,'text-3008',''),
(85,'text-4008',''),(86,'text-5008',''),(87,'text-6008',''),(88,'text-7008',''),
(89,'text-8008',''),(90,'text-9008',''),(91,'text-9',''),(92,'text-1009',''),
(93,'text-2009',''),(94,'text-3009',''),(95,'text-4009',''),(96,'text-5009',''),
(97,'text-6009',''),(98,'text-7009',''),(99,'text-8009',''),(100,'text-9009','');
set optimizer_switch='extended_keys=off';
EXPLAIN 
SELECT *  FROM t1, t2 IGNORE INDEX (PRIMARY), t3 
WHERE page_id=rev_page AND  rev_text_id=old_id  AND page_namespace=4 AND page_title='Sandbox'
ORDER BY rev_timestamp ASC LIMIT 10;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	const	PRIMARY,name_title	name_title	261	const,const	1	
1	SIMPLE	t2	ref	page_timestamp	page_timestamp	4	const	10	Using where
1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.rev_text_id	1	
set optimizer_switch='extended_keys=on';
EXPLAIN 
SELECT *  FROM t1, t2 IGNORE INDEX (PRIMARY), t3 
WHERE page_id=rev_page AND  rev_text_id=old_id  AND page_namespace=4 AND page_title='Sandbox'
ORDER BY rev_timestamp ASC LIMIT 10;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	const	PRIMARY,name_title	name_title	261	const,const	1	
1	SIMPLE	t2	ref	page_timestamp	page_timestamp	4	const	10	Using where
1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.rev_text_id	1	
DROP TABLE t1,t2,t3;
#
# MDEV-5424 SELECT using ORDER BY DESC and LIMIT produces unexpected
# results (InnoDB/XtraDB)
#
create table t1 (a bigint not null unique auto_increment, b varchar(10), primary key (a), key (b(2))) engine = myisam default character set utf8;
create table t2 (a bigint not null unique auto_increment, b varchar(10), primary key (a), key (b(2))) engine = innodb default character set utf8;
insert into t1 (b) values (null), (null), (null);
insert into t2 (b) values (null), (null), (null);
set optimizer_switch='extended_keys=on';
explain select a from t1 where b is null order by a desc limit 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t1	ref	b	b	9	const	2	Using where; Using filesort
select a from t1 where b is null order by a desc limit 2;
a
3
2
explain select a from t2 where b is null order by a desc limit 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	range	b	b	9	NULL	3	Using where; Using filesort
select a from t2 where b is null order by a desc limit 2;
a
3
2
set optimizer_switch='extended_keys=off';
explain select a from t2 where b is null order by a desc limit 2;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	range	b	b	9	NULL	3	Using where; Using filesort
select a from t2 where b is null order by a desc limit 2;
a
3
2
explain select a from t2 where b is null order by a desc;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	index	b	PRIMARY	8	NULL	3	Using where
select a from t2 where b is null order by a desc;
a
3
2
1
explain select a from t2 where b is null order by a desc,a,a;
id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
1	SIMPLE	t2	index	b	PRIMARY	8	NULL	3	Using where
select a from t2 where b is null order by a desc,a,a;
a
3
2
1
drop table t1, t2;
set optimizer_switch=@save_optimizer_switch;
set optimizer_switch=@save_ext_key_optimizer_switch;
SET SESSION STORAGE_ENGINE=DEFAULT;