Re: Oracle 8i (8.1.7) problem with a lot of simultaneous connections -> ORA-12541 No listener available

From: Stefan <sroesch3_at_attbi.com>
Date: Tue, 15 Jan 2002 05:24:42 GMT
Message-ID: <u2P08.19524$Tq.200061_at_rwcrnsc54>


Hi Tomislaw,

add the queuesize parameter in your listener.ora file in the address description. By default oracle is able to open only 16 simultaneous connections  

Shall look like

        (ADDRESS=
                (PROTOCOL = TCP)
                (HOST = your-hostname)
                (PORT = 1521)
                (QUEUESIZE = 30)
        )

Regards
Stefan

Tomislav wrote:

> I have a multithreaded application written in Windows 2k/C++ that uses OCI
> to
> access a remote Oracle 8i database. Both versions of Oracle are 8.1.7, on
> Client and Server side.
>
> I use a single OCIEnviroment handle for all threads and I initialize &
> destroy it only once with OCI_THREADED flag.
>
> Each of my threads opens a connection and executes an Select statement
> over and over again (infinitely - in this test case).
>
> When I start 16 threads at the same time, they wait a bit for opening the
> connection to the remote Oracle server (in the 100 Mbit LAN), after that
> they start
> executing simultaneously without any problems Select statements and
> fetching small resultsets.
>
> Different case is when I start like 32 threads. Then at database opening
> time some
> of them (like 6) produce "ORA-12541: no listener available" error message
> when trying to open database connection. When I try to open the connection
> again in those threads, it succeeds.
>
> When I start 64 threads, 27 of them produce "ORA-12541" and 15 of them
> produce "ORA-12541" even the second time they try to open connection as
> well. Third time they succeed and after that all of them (all 64 work at
> the same time).
>
> Is this a message of type "Network busy" or "Client busy" or whatever it
> means?
>
> Why isn't this explained better in documentation or signaled better
> through OCI return codes?
>
> --
> /Tomislav.
Received on Tue Jan 15 2002 - 06:24:42 CET

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