Re: signal handling in mysql cli

Seems that after KILL QUERY mysql-thread-id, a call to mysql_stmt_close(stmt-handle) hangs...

This did not happen in 5.6 ...

Will try 5.7.13 ...

Seb

On 06/21/2016 04:03 PM, Sebastien FLAESCH wrote:
> Hi all,
>
> The technique described in this thread is working fine with MySQL 5.6 (libmysqlclient).
>
> Basically, in a SIGINT signal handler, we establish a new connection to perform a
>
>     KILL QUERY pid
>
> ...
>
> But with 5.7 (5.7.11) we get now a different result:
>
> A) The query is still interrupted, but we no longer get an SQL error -1317.
>
> B) For some reason, the program does not want to exit() - (must investigate)
>
> Any clues?
>
>
> With mysql it's working fine:
>
> mysql> select sleep(10);
> ^C^C -- query aborted
> +-----------+
> | sleep(10) |
> +-----------+
> +-----------+
> 1 row in set (2.79 sec)
>
> mysql> \q
> Bye
>
>
>
> Thanks!
> Seb
>
> On 12/03/2014 05:25 PM, Sebastien FLAESCH wrote:
>> Hi all,
>>
>> I have a similar question regarding KILL QUERY usage:
>>
>> We have a C client program using libmysqlclient.so, it is a single-threaded program.
>>
>> When running a long query, how can I send the KILL QUERY command when a SIGINT (CTRL-C)
>> is caught? (of course we implement a signal handler, so we keep the control)
>>
>> => Is is safe to establish a new connection to the server in the signal handler, using
>> mysql_init() + mysql_real_connect(), and execute the KILL QUERY with the mysql thread
>> id I got from the initial mysql_init() / mysql_real_connect()?
>>
>> I made some tests, and it seems to work fine, the long query returns SQL error -1317:
>> "Query execution was interrupted" (which is expected)
>>
>> We want to support SQL interruption properly, so please someone from the dev team,
>> give me a clear answer... I don't want to use a side effect or undocumented feature.
>>
>> Doing all this stuff in a signal handler is certainly risky... no?
>>
>> I could not find the information in the documentation (mysql_real_connect).
>>
>> I wish there would be an API like mysql_cancel_query(), similar to Oracle's OCI
>> OCIBreak().
>>
>> Thanks!
>> Seb
>>
>>
>>
>> On 12/02/2014 05:13 PM, walter harms wrote:
>>> hi list,
>>>
>>> when i use CTRL-C to break a query that works fine in interactive mode.
>>>
>>> mysql> select sleep(10) ;
>>> ^CCtrl-C -- sending "KILL QUERY 24289" to server ...
>>> Ctrl-C -- query aborted.
>>> +-----------+
>>> | sleep(10) |
>>> +-----------+
>>> +-----------+
>>> 1 row in set (0.86 sec)
>>>
>>> but when i use the noninteractive mode
>>>    timeout 5 mysql -BAN -e "select now(); select sleep (100) ; select now() "
>>>
>>> i looks like that  but "show full processlist;" shows otherwise and that is true
>>> as a list of long running querys showed.
>>>
>>> Is there a way to make it behave like the interactive version ?
>>> Now it is a bit confusing for everyone.
>>>
>>> re,
>>>   wh
>>>
>>
>
>


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