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bug #27531: 5.1 part of the fix:

Browse Source 
- added join cache indication in EXPLAIN (Extra column).
 - prefer filesort over full scan over 
   index for ORDER BY (because it's faster).
 - when switching from REF to RANGE because
   RANGE uses longer key turn off sort on
   the head table only as the resulting 
   RANGE access is a candidate for join cache
   and we don't want to disable it by sorting
   on the first table only.
This commit is contained in:
gkodinov/kgeorge@magare.gmz
2007-05-04 18:06:06 +03:00
parent 19b9c7a8cd
commit 306371a850
31 changed files with 216 additions and 202 deletions
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236
mysql-test/r/greedy_optimizer.result
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@ -120,11 +120,11 @@ select @@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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -132,11 +132,11 @@ 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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -144,11 +144,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -156,11 +156,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -168,11 +168,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -180,11 +180,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -200,11 +200,11 @@ select @@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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -212,11 +212,11 @@ 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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -224,11 +224,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -236,11 +236,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -248,11 +248,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -260,11 +260,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -276,11 +276,11 @@ select @@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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -288,11 +288,11 @@ 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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -303,9 +303,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -315,9 +315,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -327,9 +327,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -339,9 +339,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -352,11 +352,11 @@ select @@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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -364,11 +364,11 @@ 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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -376,11 +376,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -388,11 +388,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -400,11 +400,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -412,11 +412,11 @@ 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 t2 ALL NULL NULL NULL NULL 6 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -432,11 +432,11 @@ select @@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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -444,11 +444,11 @@ 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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -456,11 +456,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -468,11 +468,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -480,11 +480,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -492,11 +492,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -508,11 +508,11 @@ select @@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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -520,11 +520,11 @@ 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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -535,9 +535,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -547,9 +547,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -559,9 +559,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -571,9 +571,9 @@ 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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where; Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
show status like 'Last_query_cost';
Variable_name Value
@ -584,11 +584,11 @@ select @@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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -596,11 +596,11 @@ 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 t1 ALL NULL NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
show status like 'Last_query_cost';
@ -608,11 +608,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -620,11 +620,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using index; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
@ -632,11 +632,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
@ -644,11 +644,11 @@ 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 t1 ALL PRIMARY NULL NULL NULL 3 Using join cache
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where; Using join cache
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using where; Using join cache
1 SIMPLE t6 ALL NULL NULL NULL NULL 18 Using where
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';