Edit File: greedy_optimizer.result
drop table if exists t1,t2,t3,t4,t5,t6,t7; create table t1 ( c11 integer,c12 integer,c13 integer,c14 integer,c15 integer,c16 integer, primary key (c11) ); create table t2 ( c21 integer,c22 integer,c23 integer,c24 integer,c25 integer,c26 integer ); create table t3 ( c31 integer,c32 integer,c33 integer,c34 integer,c35 integer,c36 integer, primary key (c31) ); create table t4 ( c41 integer,c42 integer,c43 integer,c44 integer,c45 integer,c46 integer ); create table t5 ( c51 integer,c52 integer,c53 integer,c54 integer,c55 integer,c56 integer, primary key (c51) ); create table t6 ( c61 integer,c62 integer,c63 integer,c64 integer,c65 integer,c66 integer ); create table t7 ( c71 integer,c72 integer,c73 integer,c74 integer,c75 integer,c76 integer, primary key (c71) ); insert into t1 values (1,2,3,4,5,6); insert into t1 values (2,2,3,4,5,6); insert into t1 values (3,2,3,4,5,6); insert into t2 values (1,2,3,4,5,6); insert into t2 values (2,2,3,4,5,6); insert into t2 values (3,2,3,4,5,6); insert into t2 values (4,2,3,4,5,6); insert into t2 values (5,2,3,4,5,6); insert into t2 values (6,2,3,4,5,6); insert into t3 values (1,2,3,4,5,6); insert into t3 values (2,2,3,4,5,6); insert into t3 values (3,2,3,4,5,6); insert into t3 values (4,2,3,4,5,6); insert into t3 values (5,2,3,4,5,6); insert into t3 values (6,2,3,4,5,6); insert into t3 values (7,2,3,4,5,6); insert into t3 values (8,2,3,4,5,6); insert into t3 values (9,2,3,4,5,6); insert into t4 values (1,2,3,4,5,6); insert into t4 values (2,2,3,4,5,6); insert into t4 values (3,2,3,4,5,6); insert into t4 values (4,2,3,4,5,6); insert into t4 values (5,2,3,4,5,6); insert into t4 values (6,2,3,4,5,6); insert into t4 values (7,2,3,4,5,6); insert into t4 values (8,2,3,4,5,6); insert into t4 values (9,2,3,4,5,6); insert into t4 values (10,2,3,4,5,6); insert into t4 values (11,2,3,4,5,6); insert into t4 values (12,2,3,4,5,6); insert into t5 values (1,2,3,4,5,6); insert into t5 values (2,2,3,4,5,6); insert into t5 values (3,2,3,4,5,6); insert into t5 values (4,2,3,4,5,6); insert into t5 values (5,2,3,4,5,6); insert into t5 values (6,2,3,4,5,6); insert into t5 values (7,2,3,4,5,6); insert into t5 values (8,2,3,4,5,6); insert into t5 values (9,2,3,4,5,6); insert into t5 values (10,2,3,4,5,6); insert into t5 values (11,2,3,4,5,6); insert into t5 values (12,2,3,4,5,6); insert into t5 values (13,2,3,4,5,6); insert into t5 values (14,2,3,4,5,6); insert into t5 values (15,2,3,4,5,6); insert into t6 values (1,2,3,4,5,6); insert into t6 values (2,2,3,4,5,6); insert into t6 values (3,2,3,4,5,6); insert into t6 values (4,2,3,4,5,6); insert into t6 values (5,2,3,4,5,6); insert into t6 values (6,2,3,4,5,6); insert into t6 values (7,2,3,4,5,6); insert into t6 values (8,2,3,4,5,6); insert into t6 values (9,2,3,4,5,6); insert into t6 values (10,2,3,4,5,6); insert into t6 values (11,2,3,4,5,6); insert into t6 values (12,2,3,4,5,6); insert into t6 values (13,2,3,4,5,6); insert into t6 values (14,2,3,4,5,6); insert into t6 values (15,2,3,4,5,6); insert into t6 values (16,2,3,4,5,6); insert into t6 values (17,2,3,4,5,6); insert into t6 values (18,2,3,4,5,6); insert into t7 values (1,2,3,4,5,6); insert into t7 values (2,2,3,4,5,6); insert into t7 values (3,2,3,4,5,6); insert into t7 values (4,2,3,4,5,6); insert into t7 values (5,2,3,4,5,6); insert into t7 values (6,2,3,4,5,6); insert into t7 values (7,2,3,4,5,6); insert into t7 values (8,2,3,4,5,6); insert into t7 values (9,2,3,4,5,6); insert into t7 values (10,2,3,4,5,6); insert into t7 values (11,2,3,4,5,6); insert into t7 values (12,2,3,4,5,6); insert into t7 values (13,2,3,4,5,6); insert into t7 values (14,2,3,4,5,6); insert into t7 values (15,2,3,4,5,6); insert into t7 values (16,2,3,4,5,6); insert into t7 values (17,2,3,4,5,6); insert into t7 values (18,2,3,4,5,6); insert into t7 values (19,2,3,4,5,6); insert into t7 values (20,2,3,4,5,6); insert into t7 values (21,2,3,4,5,6); select @@optimizer_search_depth; @@optimizer_search_depth 62 select @@optimizer_prune_level; @@optimizer_prune_level 1 set optimizer_search_depth=63; Warnings: Warning 1287 'optimizer-search-depth=63' is deprecated and will be removed in a future release. Please use a search depth less than 63 instead select @@optimizer_search_depth; @@optimizer_search_depth 63 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_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
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