MDEV-28073 Query performance degradation in newer MariaDB versions when using many tables

The issue was that best_extension_by_limited_search() had to go through
too many plans with the same cost as there where many EQ_REF tables.

Fixed by shortcutting EQ_REF (AND REF) when the result only contains one
row. This got the optimization time down from hours to sub seconds.

The only known downside with this patch is that in some cases a table
with ref and 1 record may be used before on EQ_REF table. The faster
optimzation phase should compensate for this.

mysql-test/main/opt_trace_index_merge.result

@@ -221,8 +221,7 @@ explain select * from t1 where a=1 or b=1	{
                   }
                 },
                 "rows_for_plan": 2,
-                "cost_for_plan": 2.884903732,
-                "estimated_join_cardinality": 2
+                "cost_for_plan": 2.884903732
               }
             ]
           },

mysql-test/main/opt_trace_index_merge_innodb.result

@@ -227,7 +227,7 @@ explain select * from t1 where pk1 != 0  and key1 = 1	{
                 },
                 "rows_for_plan": 1,
                 "cost_for_plan": 1.325146475,
-                "estimated_join_cardinality": 1
+                "pruned_by_hanging_leaf": true
               }
             ]
           },

mysql-test/main/opt_trace_security.result

@@ -107,8 +107,7 @@ select * from db1.t1	{
                   }
                 },
                 "rows_for_plan": 3,
-                "cost_for_plan": 2.605126953,
-                "estimated_join_cardinality": 3
+                "cost_for_plan": 2.605126953
               }
             ]
           },
@@ -229,8 +228,7 @@ select * from db1.v1	{
                   }
                 },
                 "rows_for_plan": 3,
-                "cost_for_plan": 2.605126953,
-                "estimated_join_cardinality": 3
+                "cost_for_plan": 2.605126953
               }
             ]
           },

mysql-test/main/subselect_sj2.result

@@ -466,11 +466,11 @@ where t0.a in ( select t1.a from t1,t2 where t2.a=t0.a and
 t1.b=t2.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
-1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	
-1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using where; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Start temporary
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using where; End temporary
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where `test`.`t2`.`a` = `test`.`t0`.`a` and `test`.`t1`.`a` = `test`.`t0`.`a` and `test`.`t1`.`b` = `test`.`t2`.`b`
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where `test`.`t1`.`a` = `test`.`t0`.`a` and `test`.`t2`.`a` = `test`.`t0`.`a` and `test`.`t2`.`b` = `test`.`t1`.`b`
 update t1 set a=3, b=11 where a=4;
 update t2 set b=11 where a=3;
 select * from t0 where t0.a in 

mysql-test/main/subselect_sj2_jcl6.result

@@ -477,11 +477,11 @@ where t0.a in ( select t1.a from t1,t2 where t2.a=t0.a and
 t1.b=t2.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
-1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
-1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using where; FirstMatch(t2); Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Start temporary; Using join buffer (flat, BKA join); Key-ordered Rowid-ordered scan
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using where; End temporary; Using join buffer (incremental, BKA join); Key-ordered Rowid-ordered scan
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where `test`.`t2`.`a` = `test`.`t0`.`a` and `test`.`t1`.`a` = `test`.`t0`.`a` and `test`.`t1`.`b` = `test`.`t2`.`b`
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where `test`.`t1`.`a` = `test`.`t0`.`a` and `test`.`t2`.`a` = `test`.`t0`.`a` and `test`.`t2`.`b` = `test`.`t1`.`b`
 update t1 set a=3, b=11 where a=4;
 update t2 set b=11 where a=3;
 # Not anymore:

mysql-test/main/subselect_sj2_mat.result

@@ -468,11 +468,11 @@ where t0.a in ( select t1.a from t1,t2 where t2.a=t0.a and
 t1.b=t2.b);
 id	select_type	table	type	possible_keys	key	key_len	ref	rows	filtered	Extra
 1	PRIMARY	t0	ALL	NULL	NULL	NULL	NULL	5	100.00	Using where
-1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	
-1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Using where; FirstMatch(t2)
+1	PRIMARY	t1	ref	a	a	5	test.t0.a	1	100.00	Start temporary
+1	PRIMARY	t2	eq_ref	PRIMARY	PRIMARY	4	test.t0.a	1	100.00	Using where; End temporary
 Warnings:
 Note	1276	Field or reference 'test.t0.a' of SELECT #2 was resolved in SELECT #1
-Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where `test`.`t2`.`a` = `test`.`t0`.`a` and `test`.`t1`.`a` = `test`.`t0`.`a` and `test`.`t1`.`b` = `test`.`t2`.`b`
+Note	1003	select `test`.`t0`.`a` AS `a` from `test`.`t2` semi join (`test`.`t1`) join `test`.`t0` where `test`.`t1`.`a` = `test`.`t0`.`a` and `test`.`t2`.`a` = `test`.`t0`.`a` and `test`.`t2`.`b` = `test`.`t1`.`b`
 update t1 set a=3, b=11 where a=4;
 update t2 set b=11 where a=3;
 select * from t0 where t0.a in 

sql/sql_select.h

@@ -989,6 +989,8 @@ class POSITION
   */
   enum sj_strategy_enum sj_strategy;
 
+  /* Type of join (EQ_REF, REF etc) */
+  enum join_type type;
   /*
     Valid only after fix_semijoin_strategies_for_picked_join_order() call:
     if sj_strategy!=SJ_OPT_NONE, this is the number of subsequent tables that