Detail of the TAF mecanism used with Rac Guard or even just RAC

Good morning,  

I have scurged the documents on this to no avail. I wish to fully understand how a cursor is replayed at the point where it left off whilst using a TAF connection.  

I have defined a TAF connection with a PRECONNECT using both Primary and Secondary connections each including a backup to each other.  

So I already have a connection to the second instance open as well as the first instance, of course.  

Boom, my instance fails then my SELECT is FAILEDOVER to the surviving instance. With the First instance as Primary I had already displayed lines 1 to 100. The client connection uses my defined backup connection: DED_PRE or DED_BASIC.  

When the second instance takes over as now the PRIMARY instance my select resumes at exactly the same place it left off.  

For clarity, my libcache update job has not updated the executed SQL from the first instance onto the second instance.  

So the cursor must be copied, re -executed and a reference to the current rownum must be passed.  

Question:
Can someone explain from where the SQL and rownum is obtained?

Regards,
Peter

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Peter Lomax
tel: 0155881546
fax: 0155881594
65-67, avenue Vladimir Illich Lénine
94110 Arcueil
SIFAC / DO-NSFM
email: plomax.ext_at_francetelecom.com  

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http://www.freelists.org/webpage/oracle-l Received on Mon Dec 06 2004 - 05:07:48 CST