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

[Jamadagni, Rajendra]

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

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-----
From: Loughmiller, Greg [mailto:[EMAIL PROTECTED]
Sent: Thursday, June 12, 2003 2:35 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: RAC, fail over and timeout .. Big Question

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-----
From: K Gopalakrishnan [mailto:[EMAIL PROTECTED]
Sent: Thursday, June 12, 2003 12:30 PM
To: Multiple recipients of list ORACLE-L
Subject: RE: RAC, fail over and timeout .. Big Question

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-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]On Behalf Of Jamadagni, Rajendra
Sent: Thursday, June 12, 2003 7:50 AM
To: Multiple recipients of list ORACLE-L
Subject: RAC, fail over and timeout .. Big Question

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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