lost connection (ORA-01089, ORA-12500) - application freezes

[lupik]

Hello,
I have a TOracleSession component (DOA 3.4.4) and try to connect to a database (9.2.0.4 server on Linux) every 60 seconds by doing:

Connected := False;
(here changing database name, login and password
which can be different from previous parameters)
Connected := True;

When the database is shut down I get ORA-01089
message first and after a minute there's ORA-12500
message and after another minute again ORA-12500. Then the database is stared and the fourth attempt to connect freezes the application. If I kill the application and start it again it works fine. What can cause the component to freeze?
Thank you for any answer in advance.

Best regards,
lupik

 

[Marco Kalter]

Are all these ORA-01089 and ORA-12500 caused by setting Connected to True or are you ding something else after a minute?

 

[lupik]

Hi,
When there's no exception I do a select sql with TOracleDataSet + while not Eof ... and reading/writing some fields. Besides I use TOracleQuery + another TOracleSession component (in a separate thread) to do inserts with a clob field but in these case I did nothing else (only Connected := False, Connected := True) because of the exceptions. Could it freeze on Connected := False? I just hanged on the fourth try and killing the application from the task manager + running it again helped.

Best regards,
lupik

 

[lupik]

I forgot to add that the Oracle server was restarted when the application was working.

lupik

 

[lupik]

Hello,
I've written a simple procedure:

with OracleSession do
for i := 0 to 10 do
try
if Connected then Connected := False;
LogonDatabase := edDB.Text;
LogonUsername := edLogin.Text;
LogonPassword := edPass.Text;
Connected := True;
except
on E : Exception do
showmessage(E.Message);
end;

I set a breakpoint on "if Connected then Connected := False;" row. After the session was connected for the first time I restarted the database server and I got the following messages (on Connected := True) after each iteration until the server was running again:
1. ORA-12500
2. ORA-12535
3. ORA-12535
4. ORA-01033.
After that the connection was finally established because the server was already on.
I ran the program again and restarted the server and I got similar messages (but without 12500):
1. ORA-03113 (this appeared on Connected := False)
2. ORA-12535
3. ORA-12535
4. ORA-01033.
Before every ORA-12535 message (timeout) there was a delay about 20 seconds. Is there any way to change this timeout value or maybe it's set on Oracle Client/Server? Do DOA show any messages (like showmessage or messagedlg - this could hang in a thread, I have only dcu so I couldn't check it) or only exceptions are raised? Please for any answer. Thank you very much in advance.

Best regards,
lupik

 

[Marco Kalter]

Direct Oracle Access does not show any messages, it merely raises exceptions in case of an error message. I'm not sure if the delay in case of a database shutdown can be altered.

 

[lupik]

Hi,
So do you have any idea why it hangs on Connected := True with Linux server (the example was checked on Windows Server)?

Best regards,
lupik

 

[Marco Kalter]

Not really, this is probably a Oracle Net / Oracle Server issue.