sysbench seems to not handle dns round-robin A records properly

[Jay Janssen]

If I give sysbench a --mysql-host that is a DNS A record round-robin, it seems to always connect to one of them -- perhaps the first one in sorted order. I'd submit each thread should do a separate DNS lookup, and it should take the first record returned. Also, if a reconnection is in play, DNS should be re-checked.

[Alexey Kopytov (akopytov)]

sysbench just calls mysql_real_connect() with the the --mysql-host value as the 'host' argument.

Does the mysql command line client connects to different hosts on repeated invokations?

[Jay Janssen (jay-janssen)]

Thanks — I am able to reproduce the problem with the mysql command line client — but only in a certain environment, very odd, but not a sysbench bug.

> On Nov 26, 2014, at 10:53 AM, Alexey Kopytov <email address hidden> wrote:
>
> sysbench just calls mysql_real_connect() with the the --mysql-host value
> as the 'host' argument.
>
> Does the mysql command line client connects to different hosts on
> repeated invokations?
>
> ** Changed in: sysbench
> Status: New => Incomplete
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1396651
>
> Title:
> sysbench seems to not handle dns round-robin A records properly
>
> Status in SysBench: a system performance benchmark:
> Incomplete
>
> Bug description:
> If I give sysbench a --mysql-host that is a DNS A record round-robin,
> it seems to always connect to one of them -- perhaps the first one in
> sorted order. I'd submit each thread should do a separate DNS lookup,
> and it should take the first record returned. Also, if a reconnection
> is in play, DNS should be re-checked.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/sysbench/+bug/1396651/+subscriptions

Jay Janssen, Managing Consultant, Percona
http://about.me/jay.janssen