*: support show ddl jobs for sub-jobs

[tangenta]

What problem does this PR solve?

Issue Number: ref #14766

Problem Summary:

This PR supports ADMIN SHOW DDL JOBS for multi-schema change.

create table t (a int, b int, c int, index i1(c), index i2(c));
insert into t values (1, 2, 3);
alter table t add column d int default 4, add index i3(c), drop column a, drop column if exists z, add column if not exists e int default 5, drop index i2, add column f int default 6, drop column b, drop index i1, add column if not exists c int;

admin show ddl jobs 1;

+--------+---------+------------+---------------------------------+--------------+-----------+----------+-----------+---------------------+---------------------+---------------------+--------+
| JOB_ID | DB_NAME | TABLE_NAME | JOB_TYPE                        | SCHEMA_STATE | SCHEMA_ID | TABLE_ID | ROW_COUNT | CREATE_TIME         | START_TIME          | END_TIME            | STATE  |
+--------+---------+------------+---------------------------------+--------------+-----------+----------+-----------+---------------------+---------------------+---------------------+--------+
|    110 | test    | t          | alter table multi-schema change | none         |         1 |      108 |         0 | 2022-07-13 11:48:56 | 2022-07-13 11:48:56 | 2022-07-13 11:48:56 | synced |
|    110 | test    | t          | add column /* subjob */         | public       |         1 |      108 |         0 | NULL                | NULL                | NULL                | done   |
|    110 | test    | t          | add index /* subjob */          | public       |         1 |      108 |         1 | NULL                | NULL                | NULL                | done   |
|    110 | test    | t          | drop column /* subjob */        | none         |         1 |      108 |         0 | NULL                | NULL                | NULL                | done   |
|    110 | test    | t          | add column /* subjob */         | public       |         1 |      108 |         0 | NULL                | NULL                | NULL                | done   |
|    110 | test    | t          | drop index /* subjob */         | none         |         1 |      108 |         0 | NULL                | NULL                | NULL                | done   |
|    110 | test    | t          | add column /* subjob */         | public       |         1 |      108 |         0 | NULL                | NULL                | NULL                | done   |
|    110 | test    | t          | drop column /* subjob */        | none         |         1 |      108 |         0 | NULL                | NULL                | NULL                | done   |
|    110 | test    | t          | drop index /* subjob */         | none         |         1 |      108 |         0 | NULL                | NULL                | NULL                | done   |
+--------+---------+------------+---------------------------------+--------------+-----------+----------+-----------+---------------------+---------------------+---------------------+--------+
9 rows in set (0.01 sec)

What is changed and how it works?

Check List

Tests

• Unit test
• Integration test
• Manual test (add detailed scripts or steps below)
• No code

Side effects

• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Breaking backward compatibility

Documentation

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Changes MySQL compatibility

Release note

Please refer to Release Notes Language Style Guide to write a quality release note.

None

[ti-chi-bot]

[REVIEW NOTIFICATION]

This pull request has been approved by:

• xhebox
• xiongjiwei

To complete the pull request process, please ask the reviewers in the list to review by filling /cc @reviewer in the comment.
After your PR has acquired the required number of LGTMs, you can assign this pull request to the committer in the list by filling /assign @committer in the comment to help you merge this pull request.

The full list of commands accepted by this bot can be found here.

Reviewer can indicate their review by submitting an approval review.
Reviewer can cancel approval by submitting a request changes review.

[xhebox]

/merge

[ti-chi-bot]

This pull request has been accepted and is ready to merge.

Commit hash: 4ac4f13

[sre-bot]

Code Coverage Details: https://codecov.io/github/pingcap/tidb/commit/aafd7f0d6053a1431432b1a7fcf20d922be5eec6

[hawkingrei]

/run-mysql-test

[hawkingrei]

/run-build

[tangenta]

/merge

[ti-chi-bot]

@tangenta: Your PR was out of date, I have automatically updated it for you.

At the same time I will also trigger all tests for you:

/run-all-tests

If the CI test fails, you just re-trigger the test that failed and the bot will merge the PR for you after the CI passes.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the ti-community-infra/tichi repository.