RE: Buffer Sort explanation
- From: "Lex de Haan" <lex.de.haan@xxxxxxxxxxxxxx>
- To: <lambu999@xxxxxxxxx>
- Date: Sun, 7 Aug 2005 20:06:39 +0200
that's indeed how I understand it. obviously, there must be some cut off number
or threshold value -- and obviously, it is highly undocumented; I don't have a
clue :-)
by the way, even if I would have a clue, these algorithms are typically
fine-tuned by Oracle development with every release, without letting us know...
kind regards,
Lex.
------------------------------------------------------------------
Steve Adams Seminar http://www.naturaljoin.nl/events/seminars.html
------------------------------------------------------------------
-----Original Message-----
Hi Lex,
If Oracle determines that if a block will be accessed multiple times by the
_same_ SQL, then it moves it to PGA. If the same can be accessed multiple times
by _different_ SQL statements it ends up in SGA? Is there a cut off number for
accessing the data block above which Oracle places it to PGA?
On 8/4/05, Lex de Haan <lex.de.haan@xxxxxxxxxxxxxx> wrote:
> a BUFFER SORT typically means that Oracle reads data blocks into
> private memory, because the block will be accessed multiple times in
> the context of the SQL statement execution. in other words, Oracle
> sacrifies some extra memory to reduce the overhead of accessing blocks
> multiple times in shared memory. this has nothing to do with sorting ...
BEGIN:VCARD
VERSION:2.1
N:de Haan;Lex
FN:Lex de Haan
ORG:Natural Join B.V.
TEL;WORK;VOICE:+31.30.2515022
TEL;HOME;VOICE:+31.30.2518795
TEL;CELL;VOICE:+31.62.2955714
TEL;WORK;FAX:+31.30.2523366
ADR;WORK:;;Pieter Breughelstraat 10;Utrecht;;3583 SK;Netherlands
LABEL;WORK;ENCODING=QUOTED-PRINTABLE:Pieter Breughelstraat 10=0D=0AUtrecht 3583
SK=0D=0ANetherlands
URL;WORK:http://www.naturaljoin.nl
EMAIL;PREF;INTERNET:lex.de.haan@xxxxxxxxxxxxxx
REV:20040224T160439Z
END:VCARD
Other related posts:
