Re: Query does not work in RAC
- From: Hans Forbrich <fuzzy.graybeard@xxxxxxxxx>
- To: Eriovaldo Andrietta <ecandrietta@xxxxxxxxx>
- Date: Sun, 14 Apr 2013 12:26:11 -0600
On 14/04/2013 10:38 AM, Eriovaldo Andrietta wrote:
>
> When we use the HINT USE_HASH , it uses temporary tablespace ?
> or it can be a bug ?
>
Again you do not provide an Oracle version. Is there a reason for not
providing critical information? Without DB Version, it is impossible to
tell whether this may be a bug or a normal thing.
Hash Join, Sort Merge Join - both use PGA (as do a lot of other things),
and temp tablespace is used - almost like swap or page file - when there
is in-memory pressure for PGA.
Statistics about your join sizes would help understand how much space is
required to fulfill the hash join. Information about your PGA, and how
similar your PGA is across the RAC nodes would also be useful.
If your statistics are up to date, and you are not running into bugs
(you have applied appropriate patches) then a general statement "Do not
use hints" is often appropriate - the side effects of hints are rarely
understood by those who use them.
My favorite statement about hints was made by Jonathan Lewis in a
seminar: Paraphrased: "One hint is rarely enough. Often you need at
least a second to counter the unintended side effect of the first."
--
//www.freelists.org/webpage/oracle-l
Other related posts:
