planner: plan cache supports Batch/PointGet converted from (primary keys) in ((...), ...)

[qw4990]

Enhancement

See the case below, it should hit the plan cache:

mysql> create table t (a int, primary key(a));
Query OK, 0 rows affected (0.01 sec)

mysql> prepare st from 'select * from t where 1=1 and a in (?, ?)';
Query OK, 0 rows affected (0.00 sec)

mysql> set @a=1, @b=2;
Query OK, 0 rows affected (0.00 sec)

mysql> execute st using @a, @b;
Empty set, 1 warning (0.00 sec)

mysql> show warnings;
+---------+------+----------------------------------------------------------------------+
| Level   | Code | Message                                                              |
+---------+------+----------------------------------------------------------------------+
| Warning | 1105 | skip prepared plan-cache: Batch/PointGet plans may be over-optimized |
+---------+------+----------------------------------------------------------------------+
1 row in set (0.00 sec)

mysql> execute st using @a, @b;
Empty set, 1 warning (0.00 sec)

mysql> select @@last_plan_from_cache;
+------------------------+
| @@last_plan_from_cache |
+------------------------+
|                      0 |
+------------------------+
1 row in set (0.00 sec)

[qw4990]

Use set @@tidb_opt_fix_control = "44830:ON" to solve this.