735 lines
		
	
	
		
			41 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
		
		
			
		
	
	
			735 lines
		
	
	
		
			41 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
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								drop table if exists t1,t2,t3,t4,t5,t6,t7;
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								create table t1 (
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								c11 integer,c12 integer,c13 integer,c14 integer,c15 integer,c16 integer,
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								primary key (c11)
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								);
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								create table t2 (
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								c21 integer,c22 integer,c23 integer,c24 integer,c25 integer,c26 integer
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								);
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								create table t3 (
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								c31 integer,c32 integer,c33 integer,c34 integer,c35 integer,c36 integer,
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								primary key (c31)
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								);
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								create table t4 (
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								c41 integer,c42 integer,c43 integer,c44 integer,c45 integer,c46 integer
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								);
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								create table t5 (
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								c51 integer,c52 integer,c53 integer,c54 integer,c55 integer,c56 integer,
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								primary key (c51)
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								);
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								create table t6 (
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								c61 integer,c62 integer,c63 integer,c64 integer,c65 integer,c66 integer
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								);
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								create table t7 (
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								c71 integer,c72 integer,c73 integer,c74 integer,c75 integer,c76 integer,
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								primary key (c71)
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								);
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								insert into t1 values (1,2,3,4,5,6);
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								insert into t1 values (2,2,3,4,5,6);
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								insert into t1 values (3,2,3,4,5,6);
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								insert into t2 values (1,2,3,4,5,6);
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								insert into t2 values (2,2,3,4,5,6);
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								insert into t2 values (3,2,3,4,5,6);
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								insert into t2 values (4,2,3,4,5,6);
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								insert into t2 values (5,2,3,4,5,6);
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								insert into t2 values (6,2,3,4,5,6);
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								insert into t3 values (1,2,3,4,5,6);
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								insert into t3 values (2,2,3,4,5,6);
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								insert into t3 values (3,2,3,4,5,6);
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								insert into t3 values (4,2,3,4,5,6);
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								insert into t3 values (5,2,3,4,5,6);
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								insert into t3 values (6,2,3,4,5,6);
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								insert into t3 values (7,2,3,4,5,6);
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								insert into t3 values (8,2,3,4,5,6);
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								insert into t3 values (9,2,3,4,5,6);
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								insert into t4 values (1,2,3,4,5,6);
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								insert into t4 values (2,2,3,4,5,6);
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								insert into t4 values (3,2,3,4,5,6);
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								insert into t4 values (4,2,3,4,5,6);
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								insert into t4 values (5,2,3,4,5,6);
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								insert into t4 values (6,2,3,4,5,6);
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								insert into t4 values (7,2,3,4,5,6);
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								insert into t4 values (8,2,3,4,5,6);
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								insert into t4 values (9,2,3,4,5,6);
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								insert into t4 values (10,2,3,4,5,6);
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								insert into t4 values (11,2,3,4,5,6);
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								insert into t4 values (12,2,3,4,5,6);
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								insert into t5 values (1,2,3,4,5,6);
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								insert into t5 values (2,2,3,4,5,6);
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								insert into t5 values (3,2,3,4,5,6);
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								insert into t5 values (4,2,3,4,5,6);
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								insert into t5 values (5,2,3,4,5,6);
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								insert into t5 values (6,2,3,4,5,6);
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								insert into t5 values (7,2,3,4,5,6);
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								insert into t5 values (8,2,3,4,5,6);
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								insert into t5 values (9,2,3,4,5,6);
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								insert into t5 values (10,2,3,4,5,6);
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								insert into t5 values (11,2,3,4,5,6);
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								insert into t5 values (12,2,3,4,5,6);
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								insert into t5 values (13,2,3,4,5,6);
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								insert into t5 values (14,2,3,4,5,6);
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								insert into t5 values (15,2,3,4,5,6);
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								insert into t6 values (1,2,3,4,5,6);
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								insert into t6 values (2,2,3,4,5,6);
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								insert into t6 values (3,2,3,4,5,6);
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								insert into t6 values (4,2,3,4,5,6);
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								insert into t6 values (5,2,3,4,5,6);
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								insert into t6 values (6,2,3,4,5,6);
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								insert into t6 values (7,2,3,4,5,6);
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								insert into t6 values (8,2,3,4,5,6);
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								insert into t6 values (9,2,3,4,5,6);
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								insert into t6 values (10,2,3,4,5,6);
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								insert into t6 values (11,2,3,4,5,6);
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								insert into t6 values (12,2,3,4,5,6);
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								insert into t6 values (13,2,3,4,5,6);
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								insert into t6 values (14,2,3,4,5,6);
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								insert into t6 values (15,2,3,4,5,6);
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								insert into t6 values (16,2,3,4,5,6);
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								insert into t6 values (17,2,3,4,5,6);
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								insert into t6 values (18,2,3,4,5,6);
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								insert into t7 values (1,2,3,4,5,6);
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								insert into t7 values (2,2,3,4,5,6);
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								insert into t7 values (3,2,3,4,5,6);
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								insert into t7 values (4,2,3,4,5,6);
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								insert into t7 values (5,2,3,4,5,6);
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								insert into t7 values (6,2,3,4,5,6);
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								insert into t7 values (7,2,3,4,5,6);
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								insert into t7 values (8,2,3,4,5,6);
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								insert into t7 values (9,2,3,4,5,6);
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								insert into t7 values (10,2,3,4,5,6);
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								insert into t7 values (11,2,3,4,5,6);
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								insert into t7 values (12,2,3,4,5,6);
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								insert into t7 values (13,2,3,4,5,6);
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								insert into t7 values (14,2,3,4,5,6);
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								insert into t7 values (15,2,3,4,5,6);
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								insert into t7 values (16,2,3,4,5,6);
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								insert into t7 values (17,2,3,4,5,6);
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								insert into t7 values (18,2,3,4,5,6);
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								insert into t7 values (19,2,3,4,5,6);
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								insert into t7 values (20,2,3,4,5,6);
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								insert into t7 values (21,2,3,4,5,6);
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								select @@optimizer_search_depth;
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								@@optimizer_search_depth
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								62
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								select @@optimizer_prune_level;
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								@@optimizer_prune_level
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								1
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								set optimizer_search_depth=63;
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								select @@optimizer_search_depth;
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								@@optimizer_search_depth
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								63
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								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
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								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
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								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
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								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
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								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
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								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
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								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
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								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
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								show status like 'Last_query_cost';
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								Variable_name	Value
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								Last_query_cost	821.837037
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								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
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								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
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								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
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								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
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								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
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								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
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								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
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								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
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								show status like 'Last_query_cost';
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								Variable_name	Value
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								Last_query_cost	821.837037
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								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
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								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
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								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
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								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
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								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
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								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
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								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
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								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
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								show status like 'Last_query_cost';
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								Variable_name	Value
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								Last_query_cost	794.837037
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								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
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								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
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								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
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								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
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								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
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								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
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								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
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								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
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								show status like 'Last_query_cost';
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								Variable_name	Value
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								Last_query_cost	794.837037
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								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
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								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
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								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
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								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
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								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
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								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
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								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
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								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
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								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
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								show status like 'Last_query_cost';
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								Variable_name	Value
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								Last_query_cost	794.837037
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| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								set optimizer_prune_level=0;
							 | 
						||
| 
								 | 
							
								select @@optimizer_prune_level;
							 | 
						||
| 
								 | 
							
								@@optimizer_prune_level
							 | 
						||
| 
								 | 
							
								0
							 | 
						||
| 
								 | 
							
								set optimizer_search_depth=0;
							 | 
						||
| 
								 | 
							
								select @@optimizer_search_depth;
							 | 
						||
| 
								 | 
							
								@@optimizer_search_depth
							 | 
						||
| 
								 | 
							
								0
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								set optimizer_search_depth=1;
							 | 
						||
| 
								 | 
							
								select @@optimizer_search_depth;
							 | 
						||
| 
								 | 
							
								@@optimizer_search_depth
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								set optimizer_search_depth=62;
							 | 
						||
| 
								 | 
							
								select @@optimizer_search_depth;
							 | 
						||
| 
								 | 
							
								@@optimizer_search_depth
							 | 
						||
| 
								 | 
							
								62
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	eq_ref	PRIMARY	PRIMARY	4	test.t2.c21	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	289.418727
							 | 
						||
| 
								 | 
							
								set optimizer_prune_level=1;
							 | 
						||
| 
								 | 
							
								select @@optimizer_prune_level;
							 | 
						||
| 
								 | 
							
								@@optimizer_prune_level
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								set optimizer_search_depth=0;
							 | 
						||
| 
								 | 
							
								select @@optimizer_search_depth;
							 | 
						||
| 
								 | 
							
								@@optimizer_search_depth
							 | 
						||
| 
								 | 
							
								0
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								set optimizer_search_depth=1;
							 | 
						||
| 
								 | 
							
								select @@optimizer_search_depth;
							 | 
						||
| 
								 | 
							
								@@optimizer_search_depth
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								set optimizer_search_depth=62;
							 | 
						||
| 
								 | 
							
								select @@optimizer_search_depth;
							 | 
						||
| 
								 | 
							
								@@optimizer_search_depth
							 | 
						||
| 
								 | 
							
								62
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c12 = t2.c21 and t2.c22 = t3.c31 and t3.c32 = t4.c41 and t4.c42 = t5.c51 and t5.c52 = t6.c61 and t6.c62 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	NULL	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t2.c22	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t4.c42	1	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t6.c62	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	821.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using index
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using index
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t1, t2, t3, t4, t5, t6, t7 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								explain select t1.c11 from t7, t6, t5, t4, t3, t2, t1 where t1.c11 = t2.c21 and t1.c12 = t3.c31 and t1.c13 = t4.c41 and t1.c14 = t5.c51 and t1.c15 = t6.c61 and t1.c16 = t7.c71 and t2.c22 = t3.c32 and t2.c23 = t4.c42 and t2.c24 = t5.c52 and t2.c25 = t6.c62 and t2.c26 = t7.c72 and t3.c33 = t4.c43 and t3.c34 = t5.c53 and t3.c35 = t6.c63 and t3.c36 = t7.c73 and t4.c42 = t5.c54 and t4.c43 = t6.c64 and t4.c44 = t7.c74 and t5.c52 = t6.c65 and t5.c53 = t7.c75 and t6.c62 = t7.c76;
							 | 
						||
| 
								 | 
							
								id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t1	ALL	PRIMARY	NULL	NULL	NULL	3	
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t2	ALL	NULL	NULL	NULL	NULL	6	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t3	eq_ref	PRIMARY	PRIMARY	4	test.t1.c12	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t4	ALL	NULL	NULL	NULL	NULL	12	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t5	eq_ref	PRIMARY	PRIMARY	4	test.t1.c14	1	Using where
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t6	ALL	NULL	NULL	NULL	NULL	18	Using where; Using join buffer
							 | 
						||
| 
								 | 
							
								1	SIMPLE	t7	eq_ref	PRIMARY	PRIMARY	4	test.t1.c16	1	Using where
							 | 
						||
| 
								 | 
							
								show status like 'Last_query_cost';
							 | 
						||
| 
								 | 
							
								Variable_name	Value
							 | 
						||
| 
								 | 
							
								Last_query_cost	794.837037
							 | 
						||
| 
								 | 
							
								drop table t1,t2,t3,t4,t5,t6,t7;
							 | 
						||
| 
								 | 
							
								CREATE TABLE t1 (a int, b int, d int, i int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t1 VALUES (1,1,1,1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t2 (b int, c int, j int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t2 VALUES (1,1,1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t2_1 (j int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t2_1 VALUES (1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t3 (c int, f int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t3 VALUES (1,1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t3_1 (f int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t3_1 VALUES (1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t4 (d int, e int, k int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t4 VALUES (1,1,1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t4_1 (k int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t4_1 VALUES (1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t5 (g int, d int, h int, l int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t5 VALUES (1,1,1,1);
							 | 
						||
| 
								 | 
							
								CREATE TABLE t5_1 (l int);
							 | 
						||
| 
								 | 
							
								INSERT INTO t5_1 VALUES (1);
							 | 
						||
| 
								 | 
							
								SET optimizer_search_depth = 3;
							 | 
						||
| 
								 | 
							
								SELECT 1
							 | 
						||
| 
								 | 
							
								FROM t1
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t2 JOIN t3 ON t3.c = t2.c
							 | 
						||
| 
								 | 
							
								) ON t2.b = t1.b
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t4 JOIN t5 ON t5.d = t4.d
							 | 
						||
| 
								 | 
							
								) ON t4.d = t1.d
							 | 
						||
| 
								 | 
							
								;
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								SELECT 1
							 | 
						||
| 
								 | 
							
								FROM t1
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t2 LEFT JOIN (t3 JOIN t3_1 ON t3.f = t3_1.f) ON t3.c = t2.c
							 | 
						||
| 
								 | 
							
								) ON t2.b = t1.b
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t4 JOIN t5 ON t5.d = t4.d
							 | 
						||
| 
								 | 
							
								) ON t4.d = t1.d
							 | 
						||
| 
								 | 
							
								;
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								SELECT 1
							 | 
						||
| 
								 | 
							
								FROM t1
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								(t2 JOIN t2_1 ON t2.j = t2_1.j) JOIN t3 ON t3.c = t2.c
							 | 
						||
| 
								 | 
							
								) ON t2.b = t1.b
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t4 JOIN t5 ON t5.d = t4.d
							 | 
						||
| 
								 | 
							
								) ON t4.d = t1.d
							 | 
						||
| 
								 | 
							
								;
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								SELECT 1
							 | 
						||
| 
								 | 
							
								FROM t1
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t2 JOIN t3 ON t3.c = t2.c
							 | 
						||
| 
								 | 
							
								) ON t2.b = t1.b
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								(t4 JOIN t4_1 ON t4.k = t4_1.k) LEFT JOIN t5 ON t5.d = t4.d
							 | 
						||
| 
								 | 
							
								) ON t4.d = t1.d
							 | 
						||
| 
								 | 
							
								;
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								SELECT 1
							 | 
						||
| 
								 | 
							
								FROM t1
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t2 JOIN t3 ON t3.c = t2.c
							 | 
						||
| 
								 | 
							
								) ON t2.b = t1.b
							 | 
						||
| 
								 | 
							
								LEFT JOIN (
							 | 
						||
| 
								 | 
							
								t4 LEFT JOIN (t5 JOIN t5_1 ON t5.l = t5_1.l) ON t5.d = t4.d
							 | 
						||
| 
								 | 
							
								) ON t4.d = t1.d
							 | 
						||
| 
								 | 
							
								;
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								1
							 | 
						||
| 
								 | 
							
								SET optimizer_search_depth = DEFAULT;
							 | 
						||
| 
								 | 
							
								DROP TABLE t1,t2,t2_1,t3,t3_1,t4,t4_1,t5,t5_1;
							 | 
						||
| 
								 | 
							
								End of 5.0 tests
							 |