server: handle kill signal during write result to connection

[wshwsh12]

What problem does this PR solve?

Issue Number: close #44009

Problem Summary:

What changed and how does it work?

Check List

Tests

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

  • I checked and no code files have been changed.

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

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[tiprow]

Hi @wshwsh12. Thanks for your PR.

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[wshwsh12]

Manual test

1. Create table t with one int column, and insert 1-8388608.
2. set @@global.tidb_enable_tmp_storage_on_oom = off; and set @@global.tidb_mem_quota_query = 5 << 30;
3. Use go-mysql-driver to query the sql "select count(1) from t group by a;", fetch 10000 rows and hang forever.
4. Wait 10 minutes and sql doesn't finished.
5. Create another session and try to kill query. kill tidb query xxxxxxxxx.
6. The memory usage is released. After the client is restored, other sql can still be queried.
   

tidb> kill tidb query 2631925768;
Query OK, 0 rows affected (0.00 sec)

tidb> show processlist;
+------------+------+-----------------+------+---------+------+---------------------------------+-----------------------------------+
| Id         | User | Host            | db   | Command | Time | State                           | Info                              |
+------------+------+-----------------+------+---------+------+---------------------------------+-----------------------------------+
| 2631925766 | root | 127.0.0.1:35256 | test | Query   |    0 | autocommit                      | show processlist                  |
| 2631925768 | root | 127.0.0.1:37406 | test | Query   |  516 | autocommit; wait query finished | select count(1) from t group by a |
+------------+------+-----------------+------+---------+------+---------------------------------+-----------------------------------+
2 rows in set (0.00 sec)

[wshwsh12]

/ok-to-test

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 13 lines in your changes are missing coverage. Please review.

Project coverage is 55.0839%. Comparing base (896afa7) to head (695292d).
Report is 1 commits behind head on master.

Additional details and impacted files

@@                Coverage Diff                @@
##             master     #52882         +/-   ##
=================================================
- Coverage   72.3871%   55.0839%   -17.3033%     
=================================================
  Files          1480       1594        +114     
  Lines        428351     600789     +172438     
=================================================
+ Hits         310071     330938      +20867     
- Misses        99029     247552     +148523     
- Partials      19251      22299       +3048     

Flag	Coverage Δ
integration	35.3845% <66.6666%> (?)
unit	71.1993% <66.6666%> (-0.0656%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
dumpling	53.9957% <ø> (ø)
parser	∅ <ø> (∅)
br	41.5890% <ø> (+0.3815%)	⬆️