Re: Doing large sort in RAM - sort workarea manipulation
Date: Sat, 12 Nov 2011 15:03:44 +0100
On 2011-11-12 13:05, Jonathan Lewis wrote:
>Since you mention Informatica, you need to consider the full life-cycle of WHY
>you are sorting. I have found cases in the past where the best strategy for
>completing an Informatica job is to use a "NOSORT" type of option because most
>of the time spent turned out to be from moving the results out to Informatica
>and then back into the database. In such cases, if you sort in the database, the
>total run time increases by the time it takes to complete the sort; whereas if
>you have a no-sort operation it's slower, but not the limiting factor in getting
>the data out to Informatica.
Thanks for sharing that.
I just want to confirm I've got Your point about NOSORT approach. So by 'NOSORT" type of option' You are referring to index access which produces rowsource in sorted order or NOSORT means forget about order by ? :) If I stick with sort elimination by CBO (nosort operation) I can imagine there are hints needed , not sure CBO will use index with large output , so what kind of hints should be used to force NOSORT sort execution ? Regards
Sprawdz za darmo zdolnosc kredytowa!
http://linkint.pl/f2a77 Received on Sat Nov 12 2011 - 08:03:44 CST