Re: [Sqlrelay-discussion] Multiple sqlr-listener processes and no connections

[Ville S. <vil...@gm...>]

Hi,

Just few more details on this:

- I run SQL Relay 0.46 with two different instances configured in
sqlrelay.conf; one for Oracle and one for MySQL.

- When the problem happens, it's always with the MySQL connections. All the
sqlr-connection-mysql processes have stopped/crashed and there are several
sqlr-listener processes for the MySQL instance. They seem to be unable to
start any sqlr-connection-mysql processes.

- Just guesswork, but could the problem be caused if for whatever reason
SQL Relay fails to login to MySQL? Would that stop the
sqlr-connection-mysql process? I've asked the MySQL admin, but we don't log
the failed login attempts. I could turn on the connection debug mode in SQL
Relay, but last time we did that, it filled the /var filesystem very fast,
so I'd need to find some disk space for that.

- I'm waiting when the problem happens next time so I can run the
"sqlr-status -id INSTANCE" command to see what the raw semaphore numbers
are. I saw an old thread that seems quite similar to this, but I'm not sure
if it's related.

Cheers,
Ville

On 4 September 2012 12:15, Ville Silventoinen
<vil...@gm...>wrote:

> Hi,
>
> I'm using SQL Relay 0.45 on RedHat 6. Sometimes SQL Relay goes into a
> state where it starts several sqlr-listener processes, but there are no
> sqlr-connection processes. The application that uses SQL Relay hangs. There
> may be a problem with RedHat and the network card we are using, which can
> cause temporary loss of network connectivity. The only cure that I've found
> is to restart SQL Relay.
>
> Today I decided to try SQL Relay 0.46. As I was running tests, our DBAs
> shutdown the test Oracle database (I wasn't aware of this). Again, the same
> situation happened: Several sqlr-listener processes and no connections.
>
> I'm looking for some insight into how I could configure SQL Relay so it
> would automatically recover from the temporary loss of network connectivity
> or database availability. Is this possible? Would it help if I set
> maxlisteners to 0, listenertimeout to 60, or tweak some other configuration
> variable?
>
> Thanks for any advice,
> Ville
>
>
>