Re: First_Rows hint

  • From: "Ghassan Salem" <salem.ghassan@xxxxxxxxx>
  • To: Christian.Antognini@xxxxxxxxxxxx
  • Date: Tue, 25 Apr 2006 19:13:09 +0200

Christian and Fred,
In all cases, Oracle does not allowcate any buffer for you, you do it in
your program. eg. in a pl/sql, if you do a select into bulk collect ...limit
X.... then PL/SQL allocates the buffers for the tables, and oracle send as
much data as requested (i.e. X rows). In a Pro*C/OCI program, you allocate
the number of rows that you want to fetch (i.e. the array size), and Oracle
will send to your program that many rows. The FIRST_ROWS hint will only
influence CBO, but has nothing to do with buffer allocation.


On 4/25/06, Christian Antognini <Christian.Antognini@xxxxxxxxxxxx> wrote:
> Fred
> >Does anyone know how big the first_rows buffer is? (If I use the hint,
> how
> >does Oracle determine how much data to bring back to me initially?)
> Mhmm... Do you mean the optimizer mode FIRST_ROWS?
> If yes, it's only an optimization goal, not the size of a buffer.
> If no, please, explain what do you mean...
> Chris
> --

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