planner: fix bug cost model for tiflash do not work

[lzmhhh123]

What problem does this PR solve?

As the title says.

What is changed and how it works?

Decouple the logic with hint read_from_storage.

Check List

Tests

• Unit test
• Integration test

A simple test for after the PR:

tidb(localhost:4001) > create table t (a int, b int, c int, primary key(a));
Query OK, 0 rows affected (1.04 sec)

tidb(localhost:4001) > insert into t values(1,1,1),(2,2,2),(3,3,4);
Query OK, 3 rows affected (0.02 sec)
Records: 3  Duplicates: 0  Warnings: 0

tidb(localhost:4001) > alter table t set tiflash replica 1 location labels 'rack', 'host', 'abc';
Query OK, 0 rows affected (1.03 sec)

tidb(localhost:4001) > desc select * from t;
+-------------------+-------+--------------+----------------------------------------------+
| id                | count | task         | operator info                                |
+-------------------+-------+--------------+----------------------------------------------+
| TableReader_7     | 3.00  | root         | data:TableScan_6                             |
| └─TableScan_6     | 3.00  | cop[tiflash] | table:t, range:[-inf,+inf], keep order:false |
+-------------------+-------+--------------+----------------------------------------------+
2 rows in set (0.00 sec)

tidb(localhost:4001) > desc select * from t where t.a = 1 or t.a = 2;
+-------------------+-------+-----------+-----------------------------------------------+
| id                | count | task      | operator info                                 |
+-------------------+-------+-----------+-----------------------------------------------+
| TableReader_6     | 1.50  | root      | data:TableScan_5                              |
| └─TableScan_5     | 1.50  | cop[tikv] | table:t, range:[1,1], [2,2], keep order:false |
+-------------------+-------+-----------+-----------------------------------------------+
2 rows in set (0.00 sec)

tidb(localhost:4001) > set @@session.tidb_isolation_read_engines="tiflash";
Query OK, 0 rows affected (0.00 sec)

tidb(localhost:4001) > desc select * from t where t.a = 1 or t.a = 2;
+---------------------+-------+--------------+----------------------------------------------+
| id                  | count | task         | operator info                                |
+---------------------+-------+--------------+----------------------------------------------+
| TableReader_7       | 1.50  | root         | data:Selection_6                             |
| └─Selection_6       | 1.50  | cop[tiflash] | or(eq(Column#1, 1), eq(Column#1, 2))         |
|   └─TableScan_5     | 1.50  | cop[tiflash] | table:t, range:[-inf,+inf], keep order:false |
+---------------------+-------+--------------+----------------------------------------------+
3 rows in set (0.00 sec)

[codecov]

Codecov Report

Merging #13111 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##            master    #13111   +/-   ##
=========================================
  Coverage   80.174%   80.174%           
=========================================
  Files          468       468           
  Lines       110557    110557           
=========================================
  Hits         88638     88638           
  Misses       15136     15136           
  Partials      6783      6783

[winoros]

lgtm

[alivxxx]

Can we add a test?

[lzmhhh123]

@lamxTyler Test was added.

[alivxxx]

LGTM

[sre-bot]

/run-all-tests