Re: [Sqlrelay-discussion] getting stuck (Oracle)

[John K. <kl...@gm...>]

Slight correction...  Clients can occasionally connect, and do a bit
more work.  Perhaps something eventually times out and gives up?
Regardless, most of the time, clients are just stuck, waiting, and the
debug output looks largely the same (i.e. most of them ending in,
"acquiring announce mutex").

On Feb 11, 2008 12:51 PM, John Klassa <kl...@gm...> wrote:
> I have a setup with two SQL Relay instances -- one just routes
> "select" statements to the other, and drops anything else.  The
> "other" is actually connected to the database, and does work.
>
> I've found that if I change the worker (the one that's actually
> connected to the DB) from having:
>
>             connections="10"
>             maxconnections="10"
>
> to having :
>
>             connections="15"
>             maxconnections="15"
>
> then after I run just a few commands through SQL Relay, it hangs.
> Clients can't connect, and no work gets done -- even though the SQL
> Relay server and the database are sitting largely idle, doing nothing.
>  No error messages anywhere (other than timeouts on the clients).
> Nothing ever frees up, and SQL Relay never does useful work again,
> until I restart it.
>
> The database user I'm connecting as has no simultaneous session limit,
> according to my DBA.  So, I'm at a bit of a loss.  It's as though
> something is getting locked, and blocking everything from then on.
>
> When I turn on debug, the connection debug files end like this (this
> is the output of "tail -2" on each):
>
> 02/11/2008 09:44:15 PST connection [7638] :     acquiring announce mutex
>
> 02/11/2008 09:43:35 PST connection [7640] :     acquiring announce mutex
>
> 02/11/2008 09:44:11 PST connection [7642] :     acquiring announce mutex
>
> 02/11/2008 09:44:24 PST connection [7644] :     acquiring announce mutex
>
> 02/11/2008 09:44:14 PST connection [7646] :     acquiring announce mutex
>
> 02/11/2008 09:44:13 PST connection [7648] :     acquiring announce mutex
>
> 02/11/2008 09:44:18 PST connection [7650] :     waiting for listener
>
> 02/11/2008 09:44:15 PST connection [7652] :     acquiring announce mutex
>
> 02/11/2008 09:43:43 PST connection [7661] :     acquiring announce mutex
>
> 02/11/2008 09:44:11 PST connection [7663] :     acquiring announce mutex
>
> 02/11/2008 09:44:10 PST connection [7665] :     acquiring announce mutex
>
> 02/11/2008 09:44:18 PST connection [7667] :     acquiring announce mutex
>
> 02/11/2008 09:44:13 PST connection [7669] :     acquiring announce mutex
>
> 02/11/2008 09:44:17 PST connection [7671] :     acquiring announce mutex
>
> 02/11/2008 09:44:18 PST connection [7673] :     acquiring announce mutex
>
> 02/11/2008 09:44:18 PST connection [7685] :     acquiring announce mutex
>
> 02/11/2008 09:44:12 PST connection [7687] :     acquiring announce mutex
>
> 02/11/2008 09:44:14 PST connection [7689] :     acquiring announce mutex
>
> 02/11/2008 09:44:19 PST connection [7691] :     acquiring announce mutex
>
> 02/11/2008 09:44:13 PST connection [7693] :     acquiring announce mutex
>
> 02/11/2008 09:44:13 PST connection [7699] :     acquiring announce mutex
>
> 02/11/2008 09:44:14 PST connection [7701] :     acquiring announce mutex
>
> 02/11/2008 09:44:18 PST connection [7703] :     waiting for listener
>
> 02/11/2008 09:44:16 PST connection [7708] :     acquiring announce mutex
>
> 02/11/2008 09:44:17 PST connection [7710] :     acquiring announce mutex
>
> 02/11/2008 09:44:18 PST connection [7712] :     acquiring announce mutex
>
> 02/11/2008 09:44:14 PST connection [7732] :     acquiring announce mutex
>
> 02/11/2008 09:44:10 PST connection [7737] :     acquiring announce mutex
>
> 02/11/2008 09:44:18 PST connection [7744] :
> preparing/executing...
>
> 02/11/2008 09:44:12 PST connection [7753] :     acquiring announce mutex
>
> So it looks like they're all waiting to acquire the announce mutex.
>
> I tried building against Oracle 9 and Oracle 10, and get this same
> result either way.
>
> (On that note, I need to post separately about Oracle 10.  I had to
> finagle it to build, there.)
>
> Anyway, any thoughts on how to fix this "announce mutex" issue?
>
> Thanks!
>