Re: problem about full scan temporary table

  • From: "Binh Pham" <binhpham15@xxxxxxxxxxx>
  • To: jonathan@xxxxxxxxxxxxxxxxxx, wqhhp@xxxxxxxxx, oracle-l@xxxxxxxxxxxxx
  • Date: Sun, 24 Sep 2006 15:17:43 +0000

Jonathan,

If someone wants to load lots of data into the GTT, based on the 1M extent size, doesn't this seem to be inefficient and may pose a performance issue due to Oracle has to keep extending?  I guess that if one wants to load lots of data (i.e. 1G+ data) into GTT, there might be other options rather than GTT.

 

Thanks.


From:  "Jonathan Lewis" <jonathan@xxxxxxxxxxxxxxxxxx>
Reply-To:  jonathan@xxxxxxxxxxxxxxxxxx
To:  <wqhhp@xxxxxxxxx>,<oracle-l@xxxxxxxxxxxxx>
Subject:  Re: problem about full scan temporary table
Date:  Sun, 24 Sep 2006 11:40:58 +0100
>
>The space of the private copy of the temporary table is allocated in
>the temporary tablespace - so it is
>allocated one extent at a time as you need the space,
>and extra extents are allocated as each extent becomes
>full.
>
>By default, the  temporary tablespace is locally managed with
>uniform extents of 1MB.
>
>
>Regards
>
>Jonathan Lewis
>http://www.oracle.com/technology/community/oracle_ace/ace1.html#lewis
>
>The Co-operative Oracle Users' FAQ
>http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
>Cost Based Oracle: Fundamentals
>http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html
>
>
>----- Original Message ----- From: "qihua wu" <wqhhp@xxxxxxxxx>
>To: <jonathan@xxxxxxxxxxxxxxxxxx>; <oracle-l@xxxxxxxxxxxxx>
>Sent: Sunday, September 24, 2006 11:36 AM
>Subject: RE: problem about full scan temporary table
>
>
>>Thanks for your reply, and I have a question based on
>>your answer.
>>
>>How does oracle know certain session will insert how
>>much data into the GTT?
>>Suppose the session first inserts 1 row, and 10
>>minutes later, inserts
>>another 1,000,000 rows. So at the beginning to operate
>>the GTT, how much
>>space will be allocated?  If the space one session
>>occupied is not
>>continuous, then I don't think HWM makes much sense.
>>
>>Thanks
>>Qihua
>
>--
>//www.freelists.org/webpage/oracle-l
>
>
-- //www.freelists.org/webpage/oracle-l

Other related posts: