Performance considerations during taking back up-- - response (5) by Nishant.Bhardwaj

Thanks Dieter for the Response..
Actaully the thing is ,we have PPI defined on A so when we do the  INSERT SELECT on the empty A_bkp table then in this case  optimizer is using the spool space and hence taking lot of time and leading to spool space issues.
I think INSERT SELECT on a NONPPI table doesnt use any spool.
Hence we thought of doing it with MERGE statement which is not throwing any ERROR.. i think  it doesnt uses any spool and does BLOCK by BLOCK ..thats why.. pls confirm..
Just  wanted to know out of curiousity  the possible other scenerios in which  MERGE  STATEMENT is Preferred.?
 
Thanks !
 
Regards,
Nishant