unable to kill query

[mxlxm]

1. What did you do?
   select sleep(10);
   hit ctrl+c with the same session to cancel, or kill id in another session.

2. What did you expect to see?
   kill the sleep query.

3. What did you see instead?
   with ctrl+c shows ^C^C -- query aborted but blocked until the sleep query completed.
   with kill id returned ok but nothing happened, sleep query completed.

4. What version of TiDB are you using (tidb-server -V)?
   master

[zimulala]

@tiancaiamao

[tiancaiamao]

This is a known issue.
We should change the builtin function implementation:

time.Sleep(duration)

to

select {
case <-time.After(duration):
case <-ctx.Done():
}

[ladrift]

I am willing to tackle this issue. But, it's not easy for a new contributor to understand the structure of source code. I cannot find the related code about the builtin function sleep and its implementation.

Is there anyone can give me some hints?

[shenli]

@ladrift The implement of Sleep() is here: https://github.com/pingcap/tidb/blob/master/expression/builtin_miscellaneous.go#L99