executor: add coprocessor cache hit ratio in explain analyze (#19948)

[ti-srebot]

cherry-pick #19948 to release-4.0

---

What problem does this PR solve?

Issue Number: close #17370

What is changed and how it works?

How it Works: add coprocessor cache hit rate in explain analyze.

here is an example:

tidb(localhost:4001) > explain analyze select * from t use index(a);
+-------------------------------+-----------+---------+-----------+------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------------+-----------------------+------+
| id                            | estRows   | actRows | task      | access object          | execution info                                                                                                                                                                                                                                           | operator info                  | memory                | disk |
+-------------------------------+-----------+---------+-----------+------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------------+-----------------------+------+
| IndexLookUp_6                 | 262400.00 | 262400  | root      |                        | time:620.513742ms, loops:258, cop_task: {num: 4, max: 5.530817ms, min: 1.51829ms, avg: 2.70883ms, p95: 5.530817ms, max_proc_keys: 2480, p95_proc_keys: 2480, tot_proc: 1ms, tot_wait: 1ms, rpc_num: 4, rpc_time: 10.816328ms, copr_cache_hit_rate: 0.75} |                                | 6.685169219970703 MB  | N/A  |
| ├─IndexFullScan_4(Build)      | 262400.00 | 262400  | cop[tikv] | table:t, index:a(a, c) | proc max:93ms, min:1ms, p80:93ms, p95:93ms, iters:275, tasks:4                                                                                                                                                                                           | keep order:false, stats:pseudo | 1.7549400329589844 MB | N/A  |
| └─TableRowIDScan_5(Probe)     | 262400.00 | 0       | cop[tikv] | table:t                | time:0ns, loops:0                                                                                                                                                                                                                                        | keep order:false, stats:pseudo | N/A                   | N/A  |
+-------------------------------+-----------+---------+-----------+------------------------+----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------------+-----------------------+------+
3 rows in set (0.62 sec)

another example with consecutive two same queries.

tidb(localhost:4001) > explain analyze select * from t;
+-----------------------+-----------+---------+-----------+---------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
---------------------------------------------------------------------+--------------------------------+----------------------+------+
| id                    | estRows   | actRows | task      | access object | execution info
                                                                     | operator info                  | memory               | disk |
+-----------------------+-----------+---------+-----------+---------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------------+----------------------+------+
| TableReader_5         | 262400.00 | 262400  | root      |               | time:398.505526ms, loops:258, cop_task: {num: 3, max: 395.43793ms, min: 126.256914ms, avg: 284.324103ms, p95: 395.43793ms, max_proc_keys: 103120, p95_proc_keys: 103120, tot_proc: 421ms, tot_wait: 11ms, rpc_num: 3, rpc_time: 852.957604ms, copr_cache_hit_rate: 0.00} | data:TableFullScan_4           | 10.83200740814209 MB | N/A  |
| └─TableFullScan_4     | 262400.00 | 262400  | cop[tikv] | table:t       | proc max:159ms, min:41ms, p80:159ms, p95:159ms, iters:269, tasks:3                                                                                                                                                                                                       | keep order:false, stats:pseudo | N/A                  | N/A  |
+-----------------------+-----------+---------+-----------+---------------+--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------------+----------------------+------+
2 rows in set (0.42 sec)

tidb(localhost:4001) > explain analyze select * from t;
+-----------------------+-----------+---------+-----------+---------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------------+-----------------------+------+
| id                    | estRows   | actRows | task      | access object | execution info                                                                                                                                                                | operator info                  | memory                | disk |
+-----------------------+-----------+---------+-----------+---------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------------------------------+-----------------------+------+
| TableReader_5         | 262400.00 | 262400  | root      |               | time:8.316905ms, loops:258, cop_task: {num: 3, max: 2.68057ms, min: 2.104203ms, avg: 2.332752ms, p95: 2.68057ms, rpc_num: 3, rpc_time: 6.982763ms, copr_cache_hit_rate: 1.00} | data:TableFullScan_4
           | 10.831978797912598 MB | N/A  |
| └─TableFullScan_4     | 262400.00 | 262400  | cop[tikv] | table:t       | proc max:159ms, min:41ms, p80:159ms, p95:159ms, iters:269, tasks:3                                                                                                            | keep order:false, st
ats:pseudo | N/A                   | N/A  |
+-----------------------+-----------+---------+-----------+---------------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+---------------------
-----------+-----------------------+------+
2 rows in set (0.02 sec)

Related changes

• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Integration test

Side effects

• Performance regression
  • Consumes more CPU

Release note

• add coprocessor cache hit ratio in explain analyze.

[ti-srebot]

/run-all-tests

[qw4990]

LGTM

[SunRunAway]

LGTM

[SunRunAway]

/merge

[ti-srebot]

Sorry @SunRunAway, you don't have permission to trigger auto merge event on this branch.
The version releasement is in progress.

[SunRunAway]

/merge

[ti-srebot]

Your auto merge job has been accepted, waiting for:

• 20092

[ti-srebot]

/run-all-tests

[ti-srebot]

/run-all-tests

[ti-srebot]

@ti-srebot merge failed.

[bb7133]

/merge

[ti-srebot]

Your auto merge job has been accepted, waiting for:

• 20076
• 20074
• 20062
• 20020

[ti-srebot]

/run-all-tests