[RADIATOR] mysql DBI timed out connections and too many open files (sockets)

[Tuure Vartiainen]

Hi,

> On 20 Apr 2017, at 13.31, Rauno Tuul <raunz at hot.ee> wrote:
> 
> I did a quick test on a random CentOS release 5.11 box with
> Radiator-4.11-1. Installed the rpm, changed only radius.cfg to the
> following:
> 
> grep -v "^#" /etc/radiator/radius.cfg
> LogDir          /var/log/radius
> DbDir           /etc/radiator
> Trace           4
> <Client DEFAULT>
>        Secret  asd
>        DupInterval 0
> </Client>
> <Realm DEFAULT>
>        <AuthBy SQL>
>                DBSource                dbi:mysql:dbname:127.0.0.1:3310
>                Timeout                 1
>                FailureBackoffTime      1
>                DBUsername              someuser
>                DBAuth                  pointlesspassword
>                AuthSelect      select 'random' from nowhere
>                AuthColumnDef   0,      User-Name, check
>                NoDefault
>        </AuthBy>
> </Realm>
> 
> It took me an hour and a half to reproduce the issue on entirely new
> environment to Radiator without any changes on OS side.
> The problem exists with debian and centos, so it's not a distro issue.
> 
> Please share the details about the try to reproduce the issue when the
> problem didn't occur. I really would like to know, where's the difference.
> 

I was now able to reproduce the problem which is caused by MySQL DB driver 
(libmysqlclient18 in Debian) leaving file handles open when a connect operation 
is interrupted by SIGALRM signal (generic Timeout in AuthBy SQL).

You can fix it by defining a timeout value for MySQL driver in DBSource, 
e.g.

DBSource   dbi:mysql:dbname:127.0.0.1:3310;mysql_connect_timeout=<seconds>

where the value is smaller than Timeout value used in AuthBy SQL.


Different MySQL driver options can be found from

https://metacpan.org/pod/DBD::mysql#Class-Methods


BR
-- 
Tuure Vartiainen <vartiait at open.com.au>

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