RE: why are some applications oracle but not RAC compatible?

I have not checked recently but in the old days if you wrote an application that used the DBMS_PIPE package you had a problem on RAC (then OPS) that both the reader and writer to the pipe needed to be connected to the same instance since the pipe is in the SGA. I would think you could probably replace the use of dbms_pipe in this case with use of the Advanced Queuing option though AQ had issues in the past on RAC with the end of the Queue pinging.

We also encountered problems using the DMBS_ALERT package to have programs wait on the database to issue an application alert where the alert was not issued from the same instance that the program was connected to while waiting. The programs would fail to alert. I think this problem may have really been an issue in DBMS_LOCK which if you asked for a user lock on instance A with instructions not to wait if the user lock is in use and the lock was in use by another session on instance A the call immediately returned with the message the lock request failed, but if you issued the request form instance B the session just waited for the session on instance A to release the user lock rather than immediately quitting like it should have.

I would not be surprised that in a few case vendors who ran into any of these and similar issues may just have never bothered to retest their applications on more modern versions of Oracle to see if the problems still exist.

Then you have the applications that were ported from another database product with minimal design change and may well not run very well on Oracle to begin with. Use RAC and such an application may well run even worse.

From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Chris King Sent: Wednesday, March 26, 2014 2:14 PM
To: oracle-l_at_freelists.org
Subject: why are some applications oracle but not RAC compatible?

Can anyone tell me why an application would be compatible with oracle but not rac? I'm assuming it must have to do with connectivity, but not sure why that isn't transparent to all applications?

Thanks in advance.

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