RE: RAC, fail over and timeout .. Big Question

From: Jamadagni, Rajendra <Rajendra.Jamadagni_at_espn.com>
Date: Thu, 12 Jun 2003 13:57:22 -0700
Message-ID: <F001.005B0BF3.20030612134507@fatcity.com>

Roy,

I'll check that ... am not sure if it is ADO, but .NET isn't going to happen here ... not anytime soon.

Raj

Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !

-----Original Message-----

From: Pardee, Roy E [mailto:[EMAIL PROTECTED]] Sent: Thursday, June 12, 2003 4:46 PM
To: Multiple recipients of list ORACLE-L Subject: RE: RAC, fail over and timeout .. Big Question

If your devs are using ADO, do you know if they've tried setting the .CommandTimeout property of the relevant Connection or Command object? I'm not sure what the analogue is in ADO.Net, tho I'd bet there is one...

Cheers,

-Roy

Roy Pardee
Programmer/Analyst/DBA
SWFPAC Lockheed Martin IT
Extension 8487
-----Original Message-----

Sent: Thursday, June 12, 2003 12:02 PM
To: Multiple recipients of list ORACLE-L

Thanks KG, Greg,

What I visualize is this ...

Specify a (sort of) timeout value. If query doesn't come back within this value, raise alert and fail over to the other side. If you get the same problem, raise the hell out of everyone and go to cache mode (good for 3-5 minutes). Hope the problem gets fixed by then.

The biggest question is how to timeout a query if it doesn't return in specified time? We got some good VB coders ... so any ideas with VB are also welcome.

Pre-connecting is something we are looking at, but sometimes application performs DML as well. So ... the plot thickens ...

I am still researching ...
Raj

Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !
-----Original Message-----

Sent: Thursday, June 12, 2003 2:35 PM
To: Multiple recipients of list ORACLE-L

It would be interesting to see if the pre-connect helps you out or not.. We are getting ready to work thru similar issues/testing...

Greg
-----Original Message-----

Sent: Thursday, June 12, 2003 12:30 PM
To: Multiple recipients of list ORACLE-L

Raj:

I am afraid, there are not much alternatives you can think of. Even the SELECT fail over
will take around few seconds since it has to attach the PGA to the second instance and run the query from where it is failovered, though you can overcome
this by enabling pre-connect.

Pls let me know if you got any nice ideas ;)

Best Regards,
K Gopalakrishnan

-----Original Message-----

Jamadagni, Rajendra
Sent: Thursday, June 12, 2003 7:50 AM
To: Multiple recipients of list ORACLE-L

Hi all,
here is a (hopefully) tricky one ...
We have a two node RAC (9202), two applications run on either side, no problems there. We have a business critical process that runs all the time on node T2. This process needs to have a set response time or it affects business. And it is written in VB. Currently we have already handled the situations when a node is down (or machine is down) it fails over to the other side and continues.
What we need to cater for is when DB is up, but sick (i.e. not responding). We need to be able to specify a timeout in the queries and when we get no response in the specified time, we need to automatically fail over to the other side.
The queries in the application are optimally written, they are sub-second or single digit second queries. So, a query taking a long time would be about 10-15 seconds.
While we are fishing for ideas, has anyone implemented anything like this? Any ideas?
Thanks in advance
Raj

Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !
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Author: Pardee, Roy E
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Received on Thu Jun 12 2003 - 15:57:22 CDT