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Home -> Community -> Mailing Lists -> Oracle-L -> Re: problem about full scan temporary table
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@jlcomp.demon.co.uk>
Reply-To: jonathan@jlcomp.demon.co.uk
To: <wqhhp@yahoo.com>,<oracle-l@freelists.org>
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@yahoo.com>
>To: <jonathan@jlcomp.demon.co.uk>; <oracle-l@freelists.org>
>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
>
>--
>http://www.freelists.org/webpage/oracle-l
>
>
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