mariadb/mysql-test/t/greedy_optimizer.test

#
# A simple test of the greedy query optimization algorithm and the switches that
# control the optimizationprocess.
#

#
# Schema
#
--disable_warnings
drop table if exists t1,t2,t3,t4,t5,t6,t7;
--enable_warnings

create table t1 (
  c11 integer,c12 integer,c13 integer,c14 integer,c15 integer,c16 integer,
  primary key (c11)
);
create table t2 (
  c21 integer,c22 integer,c23 integer,c24 integer,c25 integer,c26 integer
);
create table t3 (
  c31 integer,c32 integer,c33 integer,c34 integer,c35 integer,c36 integer,
  primary key (c31)
);
create table t4 (
  c41 integer,c42 integer,c43 integer,c44 integer,c45 integer,c46 integer
);
create table t5 (
  c51 integer,c52 integer,c53 integer,c54 integer,c55 integer,c56 integer,
  primary key (c51)
);
create table t6 (
  c61 integer,c62 integer,c63 integer,c64 integer,c65 integer,c66 integer
);
create table t7 (
  c71 integer,c72 integer,c73 integer,c74 integer,c75 integer,c76 integer,
  primary key (c71)
);

#
# Data
# cardinality(Ti) = cardinality(T(i-1)) + 3
#
insert into t1 values (1,2,3,4,5,6);
insert into t1 values (2,2,3,4,5,6);
insert into t1 values (3,2,3,4,5,6);

insert into t2 values (1,2,3,4,5,6);
insert into t2 values (2,2,3,4,5,6);
insert into t2 values (3,2,3,4,5,6);
insert into t2 values (4,2,3,4,5,6);
insert into t2 values (5,2,3,4,5,6);
insert into t2 values (6,2,3,4,5,6);

insert into t3 values (1,2,3,4,5,6);
insert into t3 values (2,2,3,4,5,6);
insert into t3 values (3,2,3,4,5,6);
insert into t3 values (4,2,3,4,5,6);
insert into t3 values (5,2,3,4,5,6);
insert into t3 values (6,2,3,4,5,6);
insert into t3 values (7,2,3,4,5,6);
insert into t3 values (8,2,3,4,5,6);
insert into t3 values (9,2,3,4,5,6);

insert into t4 values (1,2,3,4,5,6);
insert into t4 values (2,2,3,4,5,6);
insert into t4 values (3,2,3,4,5,6);
insert into t4 values (4,2,3,4,5,6);
insert into t4 values (5,2,3,4,5,6);
insert into t4 values (6,2,3,4,5,6);
insert into t4 values (7,2,3,4,5,6);
insert into t4 values (8,2,3,4,5,6);
insert into t4 values (9,2,3,4,5,6);
insert into t4 values (10,2,3,4,5,6);
insert into t4 values (11,2,3,4,5,6);
insert into t4 values (12,2,3,4,5,6);

insert into t5 values (1,2,3,4,5,6);
insert into t5 values (2,2,3,4,5,6);
insert into t5 values (3,2,3,4,5,6);
insert into t5 values (4,2,3,4,5,6);
insert into t5 values (5,2,3,4,5,6);
insert into t5 values (6,2,3,4,5,6);
insert into t5 values (7,2,3,4,5,6);
insert into t5 values (8,2,3,4,5,6);
insert into t5 values (9,2,3,4,5,6);
insert into t5 values (10,2,3,4,5,6);
insert into t5 values (11,2,3,4,5,6);
insert into t5 values (12,2,3,4,5,6);
insert into t5 values (13,2,3,4,5,6);
insert into t5 values (14,2,3,4,5,6);
insert into t5 values (15,2,3,4,5,6);

insert into t6 values (1,2,3,4,5,6);
insert into t6 values (2,2,3,4,5,6);
insert into t6 values (3,2,3,4,5,6);
insert into t6 values (4,2,3,4,5,6);
insert into t6 values (5,2,3,4,5,6);
insert into t6 values (6,2,3,4,5,6);
insert into t6 values (7,2,3,4,5,6);
insert into t6 values (8,2,3,4,5,6);
insert into t6 values (9,2,3,4,5,6);
insert into t6 values (10,2,3,4,5,6);
insert into t6 values (11,2,3,4,5,6);
insert into t6 values (12,2,3,4,5,6);
insert into t6 values (13,2,3,4,5,6);
insert into t6 values (14,2,3,4,5,6);
insert into t6 values (15,2,3,4,5,6);
insert into t6 values (16,2,3,4,5,6);
insert into t6 values (17,2,3,4,5,6);
insert into t6 values (18,2,3,4,5,6);

insert into t7 values (1,2,3,4,5,6);
insert into t7 values (2,2,3,4,5,6);
insert into t7 values (3,2,3,4,5,6);
insert into t7 values (4,2,3,4,5,6);
insert into t7 values (5,2,3,4,5,6);
insert into t7 values (6,2,3,4,5,6);
insert into t7 values (7,2,3,4,5,6);
insert into t7 values (8,2,3,4,5,6);
insert into t7 values (9,2,3,4,5,6);
insert into t7 values (10,2,3,4,5,6);
insert into t7 values (11,2,3,4,5,6);
insert into t7 values (12,2,3,4,5,6);
insert into t7 values (13,2,3,4,5,6);
insert into t7 values (14,2,3,4,5,6);
insert into t7 values (15,2,3,4,5,6);
insert into t7 values (16,2,3,4,5,6);
insert into t7 values (17,2,3,4,5,6);
insert into t7 values (18,2,3,4,5,6);
insert into t7 values (19,2,3,4,5,6);
insert into t7 values (20,2,3,4,5,6);
insert into t7 values (21,2,3,4,5,6);

#
# The actual test begins here
#

# Check the default values for the optimizer paramters

select @@plan_search_depth;
select @@heuristic;

-- This value swithes back to the old implementation of 'find_best()'
-- set plan_search_depth=63; - old (independent of the heuristic)
--
-- These are the values for the parameters that control the greedy optimizer
-- (total 6 combinations - 3 for plan_search_depth, 2 for 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 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;

set plan_search_depth=0;
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 plan_search_depth=1;
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 plan_search_depth=62;
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;

set plan_search_depth=0;
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 plan_search_depth=1;
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 plan_search_depth=62;
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;