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Complete implementation of WL#1469 "Greedy algorithm to search for an optimal execution plan",

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consisting of pos-review fixes and improvements.
This commit is contained in:
timour@mysql.com 2004-05-10 15:48:50 +03:00
parent 9f1fd5bd90
commit a840d8daad
8 changed files with 627 additions and 538 deletions
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2
mysql-test/r/distinct.result
View File

@ -388,8 +388,8 @@ SELECT DISTINCTROW email, shipcode FROM t1, t2 WHERE t1.infoID=t2.infoID;
email shipcode
test1@testdomain.com Z001
test2@testdomain.com Z001
test3@testdomain.com Z001
test2@testdomain.com R002
test3@testdomain.com Z001
SELECT DISTINCTROW email FROM t1 ORDER BY dateentered DESC;
email
test1@testdomain.com

6
mysql-test/r/func_group.result
View File

@ -183,12 +183,12 @@ insert into t2 values('BBB', 20, 1.0);
select t1.a1, t1.a2, t2.a1, t2.a2 from t1,t2;
a1 a2 a1 a2
10 aaa AAA 10
10 NULL AAA 10
10 bbb AAA 10
20 zzz AAA 10
10 aaa BBB 20
10 NULL AAA 10
10 NULL BBB 20
10 bbb AAA 10
10 bbb BBB 20
20 zzz AAA 10
20 zzz BBB 20
select max(t1.a1), max(t2.a1) from t1, t2 where t2.a2=9;
max(t1.a1) max(t2.a1)

332
mysql-test/r/greedy_optimizer.result
View File

@ -114,6 +114,82 @@ select @@plan_search_depth;
select @@heuristic;
@@heuristic
1
set plan_search_depth=63;
select @@plan_search_depth;
@@plan_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
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
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 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';
Variable_name Value
Last_query_cost 821.838037
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
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
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 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';
Variable_name Value
Last_query_cost 821.838037
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
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
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
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 794.838037
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
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
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
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 794.838037
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
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
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
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 794.838037
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
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
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
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 794.838037
set heuristic=0;
select @@heuristic;
@@heuristic
@ -136,13 +212,13 @@ Variable_name Value
Last_query_cost 821.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
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 t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
@ -160,12 +236,12 @@ Variable_name Value
Last_query_cost 274.419727
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
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 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';
Variable_name Value
@ -184,12 +260,12 @@ Variable_name Value
Last_query_cost 274.419727
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 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 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';
Variable_name Value
@ -237,8 +313,8 @@ Last_query_cost 794.838037
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
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
@ -261,8 +337,8 @@ Last_query_cost 794.838037
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1
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
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
@ -288,70 +364,6 @@ Variable_name Value
Last_query_cost 821.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
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
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
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 274.419727
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
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 t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 274.419727
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
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
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 274.419727
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 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 t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 274.419727
set plan_search_depth=63;
select @@plan_search_depth;
@@plan_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
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
@ -362,62 +374,50 @@ id select_type table type possible_keys key key_len ref rows Extra
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
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
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
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 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 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';
Variable_name Value
Last_query_cost 794.838037
Last_query_cost 274.419727
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
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 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';
Variable_name Value
Last_query_cost 274.419727
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
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t1.c12 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
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 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';
Variable_name Value
Last_query_cost 794.838037
Last_query_cost 274.419727
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 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 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';
Variable_name Value
@ -444,13 +444,13 @@ Variable_name Value
Last_query_cost 821.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t1 ALL NULL NULL NULL NULL 3
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 t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1
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
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
@ -468,16 +468,16 @@ Variable_name Value
Last_query_cost 794.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
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 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 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';
Variable_name Value
Last_query_cost 274.419727
Last_query_cost 794.838037
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
@ -492,16 +492,16 @@ Variable_name Value
Last_query_cost 794.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 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 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 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';
Variable_name Value
Last_query_cost 274.419727
Last_query_cost 794.838037
set plan_search_depth=1;
select @@plan_search_depth;
@@plan_search_depth
@ -545,8 +545,8 @@ Last_query_cost 794.838037
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1 Using index
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
@ -569,8 +569,8 @@ Last_query_cost 794.838037
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 t5 eq_ref PRIMARY PRIMARY 4 test.t1.c14 1
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
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
@ -596,70 +596,6 @@ Variable_name Value
Last_query_cost 821.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
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
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
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
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 794.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
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 t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using index
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 274.419727
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
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
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
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 794.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 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 t7 eq_ref PRIMARY PRIMARY 4 test.t1.c16 1 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 274.419727
set plan_search_depth=63;
select @@plan_search_depth;
@@plan_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
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1
@ -670,18 +606,6 @@ id select_type table type possible_keys key key_len ref rows Extra
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t7 eq_ref PRIMARY PRIMARY 4 test.t6.c62 1 Using index
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t5 eq_ref PRIMARY PRIMARY 4 test.t4.c42 1 Using where
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t3 eq_ref PRIMARY PRIMARY 4 test.t2.c22 1 Using where
1 SIMPLE t1 ALL NULL NULL NULL NULL 3 Using where
show status like 'Last_query_cost';
Variable_name Value
Last_query_cost 821.838037
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
@ -696,16 +620,16 @@ Variable_name Value
Last_query_cost 794.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12
1 SIMPLE t2 ALL NULL NULL NULL NULL 6
1 SIMPLE t1 eq_ref PRIMARY PRIMARY 4 test.t2.c21 1 Using where
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
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 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 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';
Variable_name Value
Last_query_cost 274.419727
Last_query_cost 794.838037
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
@ -720,14 +644,14 @@ Variable_name Value
Last_query_cost 794.838037
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 t6 ALL NULL NULL NULL NULL 18
1 SIMPLE t4 ALL NULL NULL NULL NULL 12 Using where
1 SIMPLE t1 ALL PRIMARY NULL NULL NULL 3
1 SIMPLE t2 ALL NULL NULL NULL NULL 6 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 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 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';
Variable_name Value
Last_query_cost 274.419727
Last_query_cost 794.838037
drop table t1,t2,t3,t4,t5,t6,t7;

8
mysql-test/r/select.result
View File

@ -1393,8 +1393,8 @@ companynr companynr
41 40
explain select distinct t2.companynr,t4.companynr from t2,t4 where t2.companynr=t4.companynr+1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t2 ALL NULL NULL NULL NULL 1199 Using temporary
1 SIMPLE t4 index NULL PRIMARY 1 NULL 12 Using where; Using index
1 SIMPLE t4 index NULL PRIMARY 1 NULL 12 Using index; Using temporary
1 SIMPLE t2 ALL NULL NULL NULL NULL 1199 Using where
select t2.fld1,t2.companynr,fld3,period from t3,t2 where t2.fld1 = 38208 and t2.fld1=t3.t2nr and period = 1008 or t2.fld1 = 38008 and t2.fld1 =t3.t2nr and period = 1008;
fld1 companynr fld3 period
038008 37 reporters 1008
@ -2314,8 +2314,8 @@ left join t4 on id3 = id4 where id2 = 1 or id4 = 1;
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE t3 system NULL NULL NULL NULL 0 const row not found
1 SIMPLE t1 ALL NULL NULL NULL NULL 2
1 SIMPLE t2 ALL NULL NULL NULL NULL 1
1 SIMPLE t4 ALL id4 NULL NULL NULL 1 Using where
1 SIMPLE t4 ALL id4 NULL NULL NULL 1
1 SIMPLE t2 ALL NULL NULL NULL NULL 1 Using where
select * from t1 left join t2 on id1 = id2 left join t3 on id1 = id3
left join t4 on id3 = id4 where id2 = 1 or id4 = 1;
id1 id2 id3 id4 id44

96
mysql-test/t/greedy_optimizer.test
View File

@ -135,28 +135,60 @@ insert into t7 values (21,2,3,4,5,6);
# The actual test begins here
#
# first check the default values for the optimizer paramters
# Check the default values for the optimizer paramters
select @@plan_search_depth;
select @@heuristic;
-- These are all possible values for the parameters that control the optimizer
-- (total 8 combinations):
-- This value swithes back to the old implementation of 'find_best()'
-- set plan_search_depth=63; - old (independent of the heuristic)
--
-- set plan_search_depth=0; -- automatic
-- set plan_search_depth=1; -- min
-- set plan_search_depth=62; -- max - default
-- set plan_search_depth=63; -- old
-- select @@plan_search_depth;
-- These are the values for the parameters that control the greedy optimizer
-- (total 6 combinations - 3 for plan_search_depth, 2 for heuristic):
--
-- set heuristic=0 -- exhaustive;
-- set heuristic=1 -- heuristic; -- default
-- select @@heuristic;
-- set plan_search_depth=0; - automatic
-- set plan_search_depth=1; - min
-- set plan_search_depth=62; - max (default)
--
-- set heuristic=0 - exhaustive;
-- set heuristic=1 - heuristic; -- default
#
# Compile some simple queries with all combinations of the query
# optimizer parameters.
# Compile several queries with all combinations of the query
# optimizer parameters. Each test query has two variants, where
# in the second variant the tables in the FROM clause are in
# inverse order to the tables in the first variant.
# Due to pre-sorting of tables before compilation, there should
# be no difference in the plans for each two such query variants.
#
# First, for reference compile the test queries with the 'old' optimization
# procedure 'find_best'. Notice that 'find_best' does not depend on the
# choice of heuristic.
set plan_search_depth=63;
select @@plan_search_depth;
-- 6-table join, chain
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
-- 6-table join, star
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
-- 6-table join, clique
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
# Test the new optimization procedures
set heuristic=0;
select @@heuristic;
@ -217,25 +249,6 @@ show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
set plan_search_depth=63;
select @@plan_search_depth;
-- 6-table join, chain
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
-- 6-table join, star
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
-- 6-table join, clique
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
set heuristic=1;
select @@heuristic;
@ -297,23 +310,4 @@ show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
set plan_search_depth=63;
select @@plan_search_depth;
-- 6-table join, chain
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
-- 6-table join, star
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
-- 6-table join, clique
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;
show status like 'Last_query_cost';
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;
show status like 'Last_query_cost';
drop table t1,t2,t3,t4,t5,t6,t7;

2
sql/mysql_priv.h
View File

@ -769,6 +769,8 @@ extern "C" pthread_handler_decl(handle_manager, arg);
void print_where(COND *cond,const char *info);
void print_cached_tables(void);
void TEST_filesort(SORT_FIELD *sortorder,uint s_length);
void print_plan(JOIN* join, double read_time, double record_count,
uint idx, const char *info);
#endif
void mysql_print_status(THD *thd);
/* key.cc */

623
sql/sql_select.cc
View File

@ -48,21 +48,21 @@ static int sort_keyuse(KEYUSE *a,KEYUSE *b);
static void set_position(JOIN *join,uint index,JOIN_TAB *table,KEYUSE *key);
static bool create_ref_for_key(JOIN *join, JOIN_TAB *j, KEYUSE *org_keyuse,
table_map used_tables);
static void find_best_combination(JOIN *join,table_map rest_tables);
static void choose_plan(JOIN *join,table_map join_tables);
static void best_access_path(JOIN *join, JOIN_TAB *s, THD *thd,
table_map rest_tables, uint idx,
table_map remaining_tables, uint idx,
double record_count, double read_time);
static void optimize_straight_join(JOIN *join, table_map rest_tables);
static void greedy_search(JOIN *join, table_map rest_tables,
static void optimize_straight_join(JOIN *join, table_map join_tables);
static void greedy_search(JOIN *join, table_map remaining_tables,
uint depth, uint heuristic);
static void find_best_limited_depth(JOIN *join, table_map rest_tables, uint idx,
double record_count, double read_time,
uint depth, uint heuristic);
static void best_extension_by_limited_search(JOIN *join,
table_map remaining_tables,
uint idx, double record_count,
double read_time, uint depth,
uint heuristic);
static uint determine_search_depth(JOIN* join);
static int join_tab_cmp(const void* ptr1, const void* ptr2);
static void print_plan(JOIN* join, double read_time, double record_count,
uint idx, const char *info);
/*
TODO: 'find_best' is here only temporarily until 'greedy_search' is
tested and approved.
@ -1994,7 +1994,7 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
if (join->const_tables != join->tables)
{
optimize_keyuse(join, keyuse_array);
find_best_combination(join,all_table_map & ~join->const_table_map);
choose_plan(join,all_table_map & ~join->const_table_map);
}
else
{
@ -2571,7 +2571,7 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
}
/*
Update some values in keyuse for faster find_best_combination() loop
Update some values in keyuse for faster choose_plan() loop
*/
static void optimize_keyuse(JOIN *join, DYNAMIC_ARRAY *keyuse_array)
@ -2640,33 +2640,41 @@ set_position(JOIN *join,uint idx,JOIN_TAB *table,KEYUSE *key)
/*
Find the best access path (e.g. indexes) from table 's' to the tables in the
partial QEP 'join', and compute the cost of the new QEP that includes 's'.
Find the best access path for an extension of a partial execution plan and
add this path to the plan.
SYNOPSIS
best_access_path()
join Valid partial QEP.
s Table access plan from join->best_ref being added to join.
rest_tables A bit-map where a bit is set for each table accessed in 'join'.
idx Index into 'join->positions' that points to the next undecided
table access plan in 'join->positions' ('s' in this case).
Thus: (idx == join->tables - card(rest_tables) - 1)
record_count The number of records acessed by the partial QEP 'join'.
read_time Time needed to execute 'join'.
join pointer to the structure providing all context info
for the query
s the table to be joined by the function
thd thread for the connection that submitted the query
remaining_tables set of tables not included into the partial plan yet
idx the length of the partial plan
record_count estimate for the number of records returned by the partial
plan
read_time the cost of the partial plan
MODIFIES
join->positions The best access path from 's' to 'join' and the
corresponding cost are stored in 'join->positions'.
DESCRIPTION
The function finds the best access path to table 's' from the passed
partial plan where an access path is the general term for any means to
access the data in 's'. An access path may use either an index or a scan,
whichever is cheaper. The input partial plan is passed via the array
'join->positions' of length 'idx'. The chosen access method for 's' and its
cost are stored in 'join->positions[idx]'.
RETURN
None
*/
static void
best_access_path(JOIN *join, // in/out
JOIN_TAB *s, // in
THD *thd, // in
table_map rest_tables, // in
uint idx, // in
double record_count, // in
double read_time) // in
best_access_path(JOIN *join,
JOIN_TAB *s,
THD *thd,
table_map remaining_tables,
uint idx,
double record_count,
double read_time)
{
KEYUSE *best_key= 0;
uint best_max_key_part= 0;
@ -2680,7 +2688,7 @@ best_access_path(JOIN *join, // in/out
DBUG_ENTER("best_access_path");
if (s->keyuse)
{ /* Use key if possible */
{ /* Use key if possible */
TABLE *table= s->table;
KEYUSE *keyuse,*start_key=0;
double best_records= DBL_MAX;
@ -2705,7 +2713,7 @@ best_access_path(JOIN *join, // in/out
uint found_part_ref_or_null= KEY_OPTIMIZE_REF_OR_NULL;
do
{
if (!(rest_tables & keyuse->used_tables) &&
if (!(remaining_tables & keyuse->used_tables) &&
!(found_ref_or_null & keyuse->optimize))
{
found_part|= keyuse->keypart_map;
@ -2724,10 +2732,10 @@ best_access_path(JOIN *join, // in/out
Assume that that each key matches a proportional part of table.
*/
if (!found_part && !ft_key)
continue; // Nothing usable found
continue; // Nothing usable found
if (rec < MATCHING_ROWS_IN_OTHER_TABLE)
rec= MATCHING_ROWS_IN_OTHER_TABLE; // Fix for small tables
rec= MATCHING_ROWS_IN_OTHER_TABLE; // Fix for small tables
/*
ft-keys require special treatment
@ -2749,7 +2757,7 @@ best_access_path(JOIN *join, // in/out
*/
if (found_part == PREV_BITS(uint,keyinfo->key_parts) &&
!found_ref_or_null)
{ /* use eq key */
{ /* use eq key */
max_key_part= (uint) ~0;
if ((keyinfo->flags & (HA_NOSAME | HA_NULL_PART_KEY)) == HA_NOSAME)
{
@ -2759,7 +2767,7 @@ best_access_path(JOIN *join, // in/out
else
{
if (!found_ref)
{ // We found a const key
{ /* We found a const key */
if (table->quick_keys.is_set(key))
records= (double) table->quick_rows[key];
else
@ -2771,14 +2779,14 @@ best_access_path(JOIN *join, // in/out
else
{
if (!(records=keyinfo->rec_per_key[keyinfo->key_parts-1]))
{ // Prefere longer keys
{ /* Prefer longer keys */
records=
((double) s->records / (double) rec *
(1.0 +
((double) (table->max_key_length-keyinfo->key_length) /
(double) table->max_key_length)));
if (records < 2.0)
records=2.0; // Can't be as good as a unique
records=2.0; /* Can't be as good as a unique */
}
}
/* Limit the number of matched rows */
@ -2874,7 +2882,7 @@ best_access_path(JOIN *join, // in/out
tmp = record_count*min(tmp,s->worst_seeks);
}
else
tmp = best_time; // Do nothing
tmp = best_time; // Do nothing
}
} /* not ft_key */
if (tmp < best_time - records/(double) TIME_FOR_COMPARE)
@ -2904,7 +2912,7 @@ best_access_path(JOIN *join, // in/out
!((s->table->file->table_flags() & HA_TABLE_SCAN_ON_INDEX) &&
! s->table->used_keys.is_clear_all() && best_key) &&
!(s->table->force_index && best_key))
{ // Check full join
{ // Check full join
ha_rows rnd_records= s->found_records;
/*
If there is a restriction on the table, assume that 25% of the
@ -2992,47 +3000,52 @@ best_access_path(JOIN *join, // in/out
idx == join->const_tables &&
s->table == join->sort_by_table &&
join->unit->select_limit_cnt >= records)
join->sort_by_table= (TABLE*) 1; // Must use temporary table
join->sort_by_table= (TABLE*) 1; // Must use temporary table
DBUG_VOID_RETURN;
}
/*
Entry point to the MySQL optimizer. Selects a query optimzation method,
sets-up initial parameters and calls the actual optimization procedure.
Selects and invokes a search strategy for an optimal query plan.
SYNOPSIS
join An unoptimized QEP.
rest_tables A bit-map where a bit is set for each table accessed in 'join'.
choose_plan()
join pointer to the structure providing all context info for
the query
join_tables set of the tables in the query
MODIFIES
join->best_positions Stores the final optimal plan.
join->best_read Stores the corresponding cost of the optimal plan.
Depending on the optimization algorithm used, may modify other memebers
of 'join'.
DESCRIPTION
The function checks user-configurable parameters that control the search
strategy for an optimal plan, selects the search method and then invokes
it. Each specific optimization procedure stores the final optimal plan in
the array 'join->best_positions', and the cost of the plan in
'join->best_read'.
RETURN
None
*/
static void
find_best_combination(JOIN *join /*in/out*/, table_map rest_tables /*in*/)
choose_plan(JOIN *join, table_map join_tables)
{
uint search_depth= join->thd->variables.plan_search_depth;
uint heuristic= join->thd->variables.heuristic;
DBUG_ENTER("find_best_combination");
DBUG_ENTER("choose_plan");
if (join->select_options & SELECT_STRAIGHT_JOIN)
{
optimize_straight_join(join, rest_tables);
optimize_straight_join(join, join_tables);
}
else
{
/*
Heuristic: pre-sort all access plans with respect to the number of records
accessed.
Heuristic: pre-sort all access plans with respect to the number of
records accessed.
*/
qsort(join->best_ref + join->const_tables, join->tables - join->const_tables,
sizeof(JOIN_TAB*), join_tab_cmp);
*/
if (search_depth == MAX_TABLES+2)
{ /*
@ -3040,14 +3053,14 @@ find_best_combination(JOIN *join /*in/out*/, table_map rest_tables /*in*/)
the greedy version. Will be removed when greedy_search is approved.
*/
join->best_read= DBL_MAX;
find_best(join,rest_tables, join->const_tables, 1.0, 0.0);
find_best(join, join_tables, join->const_tables, 1.0, 0.0);
}
else
{
if (search_depth == 0)
/* Automatically determine a reasonable value for 'search_depth' */
search_depth= determine_search_depth(join);
greedy_search(join, rest_tables, search_depth, heuristic);
greedy_search(join, join_tables, search_depth, heuristic);
}
}
@ -3059,13 +3072,17 @@ find_best_combination(JOIN *join /*in/out*/, table_map rest_tables /*in*/)
/*
Compare two JOIN_TAB objects based on the number of records accessed
so that they can be sorted by qsort.
Compare two JOIN_TAB objects based on the number of accessed records.
SYNOPSIS
join_tab_cmp()
ptr1 pointer to first JOIN_TAB object
ptr2 pointer to second JOIN_TAB object
RETURN
1 if first is bigger
-1 if second is bigger
0 if equal
1 if first is bigger
-1 if second is bigger
0 if equal
*/
static int
@ -3083,28 +3100,33 @@ join_tab_cmp(const void* ptr1, const void* ptr2)
/*
Heuristic procedure to automatically guess the degree of exhaustiveness of the
'greedy_search' procedure. The goal of this procedure is to predict the
optimization time and to select a search depth big enough to result in a
near-otimal QEP, that doesn't take too long to find.
Heuristic procedure to automatically guess a reasonable degree of
exhaustiveness for the greedy search procedure.
SYNOPSIS
determine_search_depth()
join An unoptimized or partially optimized QEP.
join pointer to the structure providing all context info for the query
DESCRIPTION
The procedure estimates the optimization time and selects a search depth
big enough to result in a near-optimal QEP, that doesn't take too long to
find. If the number of tables in the query exceeds some constant, then
search_depth is set to this constant.
NOTES
This is an extremely simplistic implementation that serves as a stub for a
more advanced analysis of the join. Ideally the search depth should be
determined by learning from old compilations, because it will depend on the
CPU power (and other factors).
determined by learning from previous query optimizations, because it will
depend on the CPU power (and other factors).
RETURN
A positive integer that specifies the search depth (and thus the
exhaustiveness) of the depth-first search algorithm used by 'greedy_search'.
exhaustiveness) of the depth-first search algorithm used by
'greedy_search'.
*/
static uint
determine_search_depth(JOIN *join /*in*/)
determine_search_depth(JOIN *join)
{
uint table_count= join->tables - join->const_tables;
uint search_depth;
@ -3125,17 +3147,35 @@ determine_search_depth(JOIN *join /*in*/)
/*
Find the best access paths for each query relation and their costs without
reordering the table access plans in a join.
This function can be applied to:
- queries with STRAIGHT_JOIN
- internally to compute the cost of an arbitrary QEP, thus 'optimize_straight_join'
can be used at any stage of the query optimization process to finalize a QEP as
it is.
Select the best ways to access the tables in a query without reordering them.
SYNOPSIS
optimize_straight_join()
join pointer to the structure providing all context info for
the query
join_tables set of the tables in the query
DESCRIPTION
Find the best access paths for each query table and compute their costs
according to their order in the array 'join->best_ref' (thus without
reordering the join tables). The function calls sequentially
'best_access_path' for each table in the query to select the best table
access method. The final optimal plan is stored in the array
'join->best_positions', and the corresponding cost in 'join->best_read'.
NOTES
This function can be applied to:
- queries with STRAIGHT_JOIN
- internally to compute the cost of an arbitrary QEP
Thus 'optimize_straight_join' can be used at any stage of the query
optimization process to finalize a QEP as it is.
RETURN
None
*/
static void
optimize_straight_join(JOIN *join /*in/out*/, table_map rest_tables /*in*/)
optimize_straight_join(JOIN *join, table_map join_tables)
{
JOIN_TAB *s;
uint idx= join->const_tables;
@ -3145,100 +3185,131 @@ optimize_straight_join(JOIN *join /*in/out*/, table_map rest_tables /*in*/)
for (JOIN_TAB **pos= join->best_ref + idx ; (s= *pos) ; pos++)
{
/* Find the best access method from 's' to the current partial plan */
best_access_path(join, s, join->thd, rest_tables, idx, record_count, read_time);
best_access_path(join, s, join->thd, join_tables, idx, record_count, read_time);
/* compute the cost of the new plan extended with 's' */
record_count*= join->positions[idx].records_read;
read_time+= join->positions[idx].read_time;
rest_tables&= ~(s->table->map);
join_tables&= ~(s->table->map);
++idx;
}
read_time+= record_count / (double) TIME_FOR_COMPARE;
if (join->sort_by_table &&
join->sort_by_table != join->positions[join->const_tables].table->table)
read_time+= record_count; // We have to make a temp table
read_time+= record_count; // We have to make a temp table
memcpy((gptr) join->best_positions, (gptr) join->positions,
sizeof(POSITION)*idx);
join->best_read= read_time;
}
/*
Find a good (possibly optimal) query evaluation plan (QEP) for the table
access plans stored in 'join->best_ref'.
Find a good, possibly optimal, query execution plan (QEP) by a greedy search.
SYNOPSIS
join An unoptimized QEP.
rest_tables A bitmap where a bit is set for each corresponding table number.
search_depth Controlls the depth of the search. The higher the value, the
longer optimizaton time and possibly the better the resulting
plan. The lower the value, the fewer alternative plans are
estimated, but the more likely to get a bad QEP.
(0 < search_depth)
heuristic Specifies the pruning heuristics that should be applied during
optimization. Values: 0 = EXHAUSTIVE, 1 = PRUNE_BY_TIME_OR_ROWS.
join pointer to the structure providing all context info
for the query
remaining_tables set of tables not included into the partial plan yet
search_depth controlls the exhaustiveness of the search
heuristic the pruning heuristics that should be applied during
search
DESCRIPTION
The search procedure uses a hybrid greedy/exhaustive search with controlled
exhaustiveness. The search is performed in N = card(rest_tables) steps.
Each step uses a procedure to estimate how promising is each of the
unoptimized tables, selects the most promising table, and extends the
current partial QEP with that table.
Currently this estimate is performed by calling 'find_best_limited_depth'
to evaluate all extensions of the current QEP with size 'search_depth'.
The most 'promising' table is the one with least expensive extension.
exhaustiveness. The search is performed in N = card(remaining_tables)
steps. Each step evaluates how promising is each of the unoptimized tables,
selects the most promising table, and extends the current partial QEP with
that table. Currenly the most 'promising' table is the one with least
expensive extension.
There are two extreme cases:
1. When (card(rest_tables) < search_depth), the estimate finds the best
1. When (card(remaining_tables) < search_depth), the estimate finds the best
complete continuation of the partial QEP. This continuation can be
used directly as a result of the search.
2. When (search_depth == 1) the 'find_best_limited_depth' consideres the
extension of the current QEP with each of the remaining unoptimized
tables.
2. When (search_depth == 1) the 'best_extension_by_limited_search'
consideres the extension of the current QEP with each of the remaining
unoptimized tables.
All other cases are in-between these two extremes. Thus the parameter
'search_depth' controlls the exhaustiveness of the search.
'search_depth' controlls the exhaustiveness of the search. The higher the
value, the longer the optimizaton time and possibly the better the
resulting plan. The lower the value, the fewer alternative plans are
estimated, but the more likely to get a bad QEP.
MODIFIES
Intermediate and final results of the procedure are stored in 'join':
All intermediate and final results of the procedure are stored in 'join':
join->positions modified for every partial QEP that is explored
join->best_positions modified for the current best complete QEP
join->best_read modified for the current best complete QEP
join->best_ref might be partially reordered
The final optimal plan is stored in 'join->best_positions'. The
corresponding cost of the optimal plan is in 'join->best_read'.
The final optimal plan is stored in 'join->best_positions', and its
corresponding cost in 'join->best_read'.
NOTES
The following pseudocode describes the algorithm of 'greedy_search':
procedure greedy_search
input: remaining_tables
output: pplan;
{
pplan = <>;
do {
(t, a) = best_extension(pplan, remaining_tables);
pplan = concat(pplan, (t, a));
remaining_tables = remaining_tables - t;
} while (remaining_tables != {})
return pplan;
}
where 'best_extension' is a placeholder for a procedure that selects the
most "promising" of all tables in 'remaining_tables'.
Currently this estimate is performed by calling
'best_extension_by_limited_search' to evaluate all extensions of the
current QEP of size 'search_depth', thus the complexity of 'greedy_search'
mainly depends on that of 'best_extension_by_limited_search'.
If 'best_extension()' == 'best_extension_by_limited_search()', then the
worst-case complexity of this algorithm is <=
O(N*N^search_depth/search_depth). When serch_depth >= N, then the
complexity of greedy_search is O(N!).
In the future, 'greedy_search' might be extended to support other
implementations of 'best_extension', e.g. some simpler quadratic procedure.
RETURN
None
*/
static void
greedy_search(JOIN *join, // in/out
table_map rest_tables, // in
uint search_depth, // in
uint heuristic) // in
greedy_search(JOIN *join,
table_map remaining_tables,
uint search_depth,
uint heuristic)
{
double record_count= 1.0;
double read_time= 0.0;
uint idx= join->const_tables; // index into 'join->best_ref'
uint best_idx;
uint rest_size; // cardinality of rest_tables
uint rem_size; // cardinality of remaining_tables
POSITION best_pos;
JOIN_TAB *best_table; // the next plan node to be added to the curr QEP
DBUG_ENTER("greedy_search");
/* number of tables that remain to be optimized */
rest_size= my_count_bits(rest_tables);
rem_size= my_count_bits(remaining_tables);
do {
/* Find the extension of the current QEP with the lowest cost */
join->best_read= DBL_MAX;
find_best_limited_depth(join, rest_tables, idx, record_count, read_time,
search_depth, heuristic);
best_extension_by_limited_search(join, remaining_tables, idx, record_count,
read_time, search_depth, heuristic);
if (rest_size <= search_depth)
if (rem_size <= search_depth)
{
/*
'join->best_positions' contains a complete optimal extension of the
current partial QEP.
*/
/*
'join->best_positions' contains a complete optimal extension of the
current partial QEP.
*/
DBUG_EXECUTE("opt", print_plan(join, read_time, record_count,
join->tables, "optimal"););
join->tables, "optimal"););
DBUG_VOID_RETURN;
}
@ -3246,8 +3317,9 @@ greedy_search(JOIN *join, // in/out
best_pos= join->best_positions[idx];
best_table= best_pos.table;
/*
Each subsequent loop of 'find_best_limited_depth' uses 'join->positions'
for cost estimates, therefore we have to update its value.
Each subsequent loop of 'best_extension_by_limited_search' uses
'join->positions' for cost estimates, therefore we have to update its
value.
*/
join->positions[idx]= best_pos;
@ -3264,8 +3336,8 @@ greedy_search(JOIN *join, // in/out
record_count*= join->positions[idx].records_read;
read_time+= join->positions[idx].read_time;
rest_tables&= ~(best_table->table->map);
--rest_size;
remaining_tables&= ~(best_table->table->map);
--rem_size;
++idx;
DBUG_EXECUTE("opt",
@ -3275,98 +3347,149 @@ greedy_search(JOIN *join, // in/out
/*
Find an optimal ordering of the table access plans in 'join->best_ref' for
the tables contained in 'rest_tables'.
Find a good, possibly optimal, query execution plan (QEP) by a possibly
exhaustive search.
SYNOPSIS
join Valid partial QEP. When 'find_best_limited_depth' is called for
the first time, 'join->best_read' must be set to the largest
possible value (e.g. DBL_MAX).
rest_tables A bit-map where a bit is set for each table accessed in 'join'.
idx - length of the partial QEP 'join->positions',
- since a depth-first search is used, also corresponds to the
current depth of the search tree,
- also an index in the array 'join->best_ref'.
record_count The current best number of records.
(record_count >= 0)
read_time The current best execution time.
(read_time >= 0)
search_depth The maximum depth of the recursion and thus the size of the
found optimal plan.
(0 < search_depth <= join->tables+1)
heuristic Specifies the pruning heuristics that should be applied during
optimization. Values: 0 = EXHAUSTIVE, 1 = PRUNE_BY_TIME_OR_ROWS.
best_extension_by_limited_search()
join pointer to the structure providing all context info for
the query
remaining_tables set of tables not included into the partial plan yet
idx length of the partial QEP in 'join->positions';
since a depth-first search is used, also corresponds to
the current depth of the search tree;
also an index in the array 'join->best_ref';
record_count estimate for the number of records returned by the best
partial plan
read_time the cost of the best partial plan
search_depth maximum depth of the recursion and thus size of the found
optimal plan (0 < search_depth <= join->tables+1).
heuristic pruning heuristics that should be applied during optimization
(values: 0 = EXHAUSTIVE, 1 = PRUNE_BY_TIME_OR_ROWS)
DESCRIPTION
The procedure uses a recursive depth-first search that may optionally use
pruning heuristics to reduce the search space. Each recursive step adds one
more table to the input partial QEP 'join'. The parameter 'search_depth'
provides control over the recursion depth, and thus the size of the
resulting optimal plan.
The procedure searches for the optimal ordering of the query tables in set
'remaining_tables' of size N, and the corresponding optimal access paths to each
table. The choice of a table order and an access path for each table
constitutes a query execution plan (QEP) that fully specifies how to
execute the query.
The maximal size of the found plan is controlled by the parameter
'search_depth'. When search_depth == N, the resulting plan is complete and
can be used directly as a QEP. If search_depth < N, the found plan consists
of only some of the query tables. Such "partial" optimal plans are useful
only as input to query optimization procedures, and cannot be used directly
to execute a query.
The algorithm begins with an empty partial plan stored in 'join->positions'
and a set of N tables - 'remaining_tables'. Each step of the algorithm
evaluates the cost of the partial plan extended by all access plans for
each of the relations in 'remaining_tables', expands the current partial
plan with the access plan that results in lowest cost of the expanded
partial plan, and removes the corresponding relation from
'remaining_tables'. The algorithm continues until it either constructs a
complete optimal plan, or constructs an optimal plartial plan with size =
search_depth.
MODIFIES
Intermediate and final results of the procedure are stored in 'join':
join->positions modified for every partial QEP that is explored
join->best_positions modified for the current best complete QEP
join->best_read modified for the current best complete QEP
The final optimal plan is stored in 'join->best_positions'. The
corresponding cost of the optimal plan is in 'join->best_read'.
NOTES
The procedure uses a recursive depth-first search where the depth of the
recursion (and thus the exhaustiveness of the search) is controlled by the
parameter 'search_depth'.
The pseudocode below describes the algorithm of
'best_extension_by_limited_search'. The worst-case complexity of this
algorithm is O(N*N^search_depth/search_depth). When serch_depth >= N, then
the complexity of greedy_search is O(N!).
procedure best_extension_by_limited_search(
pplan in, // in, partial plan of tables-joined-so-far
pplan_cost, // in, cost of pplan
remaining_tables, // in, set of tables not referenced in pplan
best_plan_so_far, // in/out, best plan found so far
best_plan_so_far_cost,// in/out, cost of best_plan_so_far
search_depth) // in, maximum size of the plans being considered
{
for each table T from remaining_tables
{
// Calculate the cost of using table T as above
cost = complex-series-of-calculations;
// Add the cost to the cost so far.
pplan_cost+= cost;
if (pplan_cost >= best_plan_so_far_cost)
// pplan_cost already too great, stop search
continue;
pplan= expand pplan by best_access_method;
remaining_tables= remaining_tables - table T;
if (remaining_tables is not an empty set
and
search_depth > 1)
{
best_extension_by_limited_search(pplan, pplan_cost,
remaining_tables,
best_plan_so_far,
best_plan_so_far_cost,
search_depth - 1);
}
else
{
best_plan_so_far_cost= pplan_cost;
best_plan_so_far= pplan;
}
}
}
IMPLEMENTATION
When 'best_extension_by_limited_search' is called for the first time,
'join->best_read' must be set to the largest possible value (e.g. DBL_MAX).
The actual implementation provides a way to optionally use pruning
heuristics (controlled by the parameter 'heuristic') to reduce the search
space by skipping some partial plans.
The parameter 'search_depth' provides control over the recursion
depth, and thus the size of the resulting optimal plan.
RETURN
None
*/
static void
find_best_limited_depth(JOIN *join, // in/out
table_map rest_tables, // in
uint idx, // in
double record_count, // in
double read_time, // in
uint search_depth, // in
uint heuristic) // in
best_extension_by_limited_search(JOIN *join,
table_map remaining_tables,
uint idx,
double record_count,
double read_time,
uint search_depth,
uint heuristic)
{
THD *thd= join->thd;
DBUG_ENTER("find_best_limited_depth");
/*
'join' is either the best partial QEP with 'search_depth' relations,
or the best complete QEP so far, whichever is smaller.
*/
if ((search_depth == 0) || !rest_tables)
{
read_time+= record_count / (double) TIME_FOR_COMPARE;
if (join->sort_by_table &&
join->sort_by_table != join->positions[join->const_tables].table->table)
read_time+= record_count; // We have to make a temp table
if ((search_depth == 0) || (read_time < join->best_read))
{
memcpy((gptr) join->best_positions, (gptr) join->positions,
sizeof(POSITION)*idx);
join->best_read= read_time;
}
DBUG_EXECUTE("opt",
print_plan(join, read_time, record_count, idx, "full_plan"););
DBUG_VOID_RETURN;
}
DBUG_ENTER("best_extension_by_limited_search");
/*
'join' is a partial plan with lower cost than the best plan so far,
so continue expanding it further with the tables in 'rest_tables'.
so continue expanding it further with the tables in 'remaining_tables'.
*/
JOIN_TAB *s;
double best_record_count= DBL_MAX;
double best_read_time= DBL_MAX;
DBUG_EXECUTE("opt",
print_plan(join, read_time, record_count, idx, "part_plan"););
print_plan(join, read_time, record_count, idx, "part_plan"););
for (JOIN_TAB **pos= join->best_ref + idx ; (s= *pos) ; pos++)
{
table_map real_table_bit= s->table->map;
if ((rest_tables & real_table_bit) && !(rest_tables & s->dependent))
if ((remaining_tables & real_table_bit) && !(remaining_tables & s->dependent))
{
double current_record_count, current_read_time;
/* Find the best access method from 's' to the current partial plan */
best_access_path(join, s, thd, rest_tables, idx, record_count, read_time);
best_access_path(join, s, thd, remaining_tables, idx, record_count, read_time);
/* Compute the cost of extending the plan with 's' */
current_record_count= record_count * join->positions[idx].records_read;
current_read_time= read_time + join->positions[idx].read_time;
@ -3394,7 +3517,7 @@ find_best_limited_depth(JOIN *join, // in/out
if (best_record_count >= current_record_count &&
best_read_time >= current_read_time &&
/* TODO: What is the reasoning behind this condition? */
(!(s->key_dependent & rest_tables) ||
(!(s->key_dependent & remaining_tables) ||
join->positions[idx].records_read < 2.0))
{
best_record_count= current_record_count;
@ -3409,95 +3532,45 @@ find_best_limited_depth(JOIN *join, // in/out
}
}
/* Recursively expand the current partial plan */
swap(JOIN_TAB*, join->best_ref[idx], *pos);
find_best_limited_depth(join, rest_tables & ~real_table_bit, idx+1,
current_record_count, current_read_time,
search_depth-1, heuristic);
if (thd->killed)
DBUG_VOID_RETURN;
swap(JOIN_TAB*, join->best_ref[idx], *pos);
if ( (search_depth > 1) && (remaining_tables & ~real_table_bit) )
{ /* Recursively expand the current partial plan */
swap(JOIN_TAB*, join->best_ref[idx], *pos);
best_extension_by_limited_search(join,
remaining_tables & ~real_table_bit,
idx + 1,
current_record_count,
current_read_time,
search_depth - 1,
heuristic);
if (thd->killed)
DBUG_VOID_RETURN;
swap(JOIN_TAB*, join->best_ref[idx], *pos);
}
else
{ /*
'join' is either the best partial QEP with 'search_depth' relations,
or the best complete QEP so far, whichever is smaller.
*/
current_read_time+= current_record_count / (double) TIME_FOR_COMPARE;
if (join->sort_by_table &&
join->sort_by_table != join->positions[join->const_tables].table->table)
/* We have to make a temp table */
current_read_time+= current_record_count;
if ((search_depth == 1) || (current_read_time < join->best_read))
{
memcpy((gptr) join->best_positions, (gptr) join->positions,
sizeof(POSITION) * (idx + 1));
join->best_read= current_read_time;
}
DBUG_EXECUTE("opt",
print_plan(join, current_read_time, current_record_count, idx, "full_plan"););
}
}
}
DBUG_VOID_RETURN;
}
/*
Print the current state of a 'join' that changes during query optimization.
Used to trace the 'find_best_xxx' optimizer functions.
TODO: move to sql_test.cc?
*/
void
print_plan(JOIN* join, double read_time, double record_count,
uint idx, const char *info)
{
uint i;
POSITION pos;
JOIN_TAB *join_table;
JOIN_TAB **plan_nodes;
TABLE* table;
DBUG_LOCK_FILE;
if (join->best_read == DBL_MAX)
{
fprintf(DBUG_FILE,"%s; idx:%u, best: DBL_MAX, current:%g\n",
info, idx, read_time);
}
else
{
fprintf(DBUG_FILE,"%s; idx: %u, best: %g, current: %g\n",
info, idx, join->best_read, read_time);
}
/* Print the tables in JOIN->positions */
fputs(" POSITIONS: ", DBUG_FILE);
for (i= 0; i < idx ; i++)
{
pos = join->positions[i];
table= pos.table->table;
if (table)
fputs(table->real_name, DBUG_FILE);
fputc(' ', DBUG_FILE);
}
fputc('\n', DBUG_FILE);
/*
Print the tables in JOIN->best_positions only if at least one complete plan
has been found. An indicator for this is the value of 'join->best_read'.
*/
fputs("BEST_POSITIONS: ", DBUG_FILE);
if (join->best_read < DBL_MAX)
{
for (i= 0; i < idx ; i++)
{
pos= join->best_positions[i];
table= pos.table->table;
if (table)
fputs(table->real_name, DBUG_FILE);
fputc(' ', DBUG_FILE);
}
}
fputc('\n', DBUG_FILE);
/* Print the tables in JOIN->best_ref */
fputs(" BEST_REF: ", DBUG_FILE);
for (plan_nodes= join->best_ref ; *plan_nodes ; plan_nodes++)
{
join_table= (*plan_nodes);
fputs(join_table->table->real_name, DBUG_FILE);
fprintf(DBUG_FILE, "(%u,%u,%u)",
join_table->found_records, join_table->records, join_table->read_time);
fputc(' ', DBUG_FILE);
}
fputc('\n', DBUG_FILE);
DBUG_UNLOCK_FILE;
}
/*
TODO: this function is here only temporarily until 'greedy_search' is
tested and accepted.

96
sql/sql_test.cc
View File

@ -232,6 +232,102 @@ TEST_join(JOIN *join)
DBUG_VOID_RETURN;
}
/*
Print the current state during query optimization.
SYNOPSIS
print_plan()
join pointer to the structure providing all context info for
the query
read_time the cost of the best partial plan
record_count estimate for the number of records returned by the best
partial plan
idx length of the partial QEP in 'join->positions';
also an index in the array 'join->best_ref';
info comment string to appear above the printout
DESCRIPTION
This function prints to the log file DBUG_FILE the members of 'join' that
are used during query optimization (join->positions, join->best_positions,
and join->best_ref) and few other related variables (read_time,
record_count).
Useful to trace query optimizer functions.
RETURN
None
*/
void
print_plan(JOIN* join, double read_time, double record_count,
uint idx, const char *info)
{
uint i;
POSITION pos;
JOIN_TAB *join_table;
JOIN_TAB **plan_nodes;
TABLE* table;
if (info == 0)
info= "";
DBUG_LOCK_FILE;
if (join->best_read == DBL_MAX)
{
fprintf(DBUG_FILE,"%s; idx:%u, best: DBL_MAX, current:%g\n",
info, idx, read_time);
}
else
{
fprintf(DBUG_FILE,"%s; idx: %u, best: %g, current: %g\n",
info, idx, join->best_read, read_time);
}
/* Print the tables in JOIN->positions */
fputs(" POSITIONS: ", DBUG_FILE);
for (i= 0; i < idx ; i++)
{
pos = join->positions[i];
table= pos.table->table;
if (table)
fputs(table->real_name, DBUG_FILE);
fputc(' ', DBUG_FILE);
}
fputc('\n', DBUG_FILE);
/*
Print the tables in JOIN->best_positions only if at least one complete plan
has been found. An indicator for this is the value of 'join->best_read'.
*/
fputs("BEST_POSITIONS: ", DBUG_FILE);
if (join->best_read < DBL_MAX)
{
for (i= 0; i < idx ; i++)
{
pos= join->best_positions[i];
table= pos.table->table;
if (table)
fputs(table->real_name, DBUG_FILE);
fputc(' ', DBUG_FILE);
}
}
fputc('\n', DBUG_FILE);
/* Print the tables in JOIN->best_ref */
fputs(" BEST_REF: ", DBUG_FILE);
for (plan_nodes= join->best_ref ; *plan_nodes ; plan_nodes++)
{
join_table= (*plan_nodes);
fputs(join_table->table->real_name, DBUG_FILE);
fprintf(DBUG_FILE, "(%u,%u,%u)",
join_table->found_records, join_table->records, join_table->read_time);
fputc(' ', DBUG_FILE);
}
fputc('\n', DBUG_FILE);
DBUG_UNLOCK_FILE;
}
#endif
typedef struct st_debug_lock