wait_timeout used instead of interactive_timeout

[morgo]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. What did you do?

Currently wait_timeout is also applicable for interactive sessions (i.e. mysql cli tool). The MySQL compatible behavior is as follows:

2. What did you expect to see?

session1> set global wait_timeout = 5;
session1> set global interactive_timeout = 100;
..
session1> show global variables like 'wait_timeout';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 5     |
+---------------+-------+
1 row in set (0.00 sec)

session1> show global variables like 'interactive_timeout';
+---------------------+-------+
| Variable_name       | Value |
+---------------------+-------+
| interactive_timeout | 100   |
+---------------------+-------+
1 row in set (0.01 sec)

Then control +c and start a new session:

session2> show variables like 'wait_timeout';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 100   |
+---------------+-------+
1 row in set (0.00 sec)

session2> show variables like 'interactive_timeout';
+---------------------+-------+
| Variable_name       | Value |
+---------------------+-------+
| interactive_timeout | 100   |
+---------------------+-------+
1 row in set (0.01 sec)

Because the session sets the interactive bit, the interactive_timeout is actually copied over the wait_timeout. The global wait_timeout is still 5:

session2> show global variables like 'wait_timeout';
+---------------+-------+
| Variable_name | Value |
+---------------+-------+
| wait_timeout  | 5     |
+---------------+-------+
1 row in set (0.00 sec)

3. What did you see instead?

4. What version of TiDB are you using (tidb-server -V or run select tidb_version(); on TiDB)?

[morgo]

@hhxcc If you are up for it, here is how interactive_timeout behaves :-)

[lysu]

@hhxcc we can check CLIENT_INTERACTIVE in ClientCapability to choosen current session timeout
init value https://dev.mysql.com/doc/internals/en/capability-flags.html#packet-Protocol::CapabilityFlags 😆

[hhu-cc]

@morgo @lysu thank you , I would like to do this.