Re: Update Statements and Exadata

From: David Fitzjarrell <oratune_at_yahoo.com>
Date: Sun, 9 Dec 2012 02:09:53 -0800 (PST)
Message-ID: <1355047793.113.YahooMailNeo_at_web121603.mail.ne1.yahoo.com>

Basically serial processing does not perform direct path reads where parallel does.� Since one criteria for smart scans is utilizing direct path reads you don't get them with serial processing.� You could, if you really wanted to, set _serial_direct_path to true (it's false by default) but that could introduce performance problems and slowdowns.
�

David Fitzjarrell
�

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 From: coskan gundogar <coskan_at_gmail.com> To: Oracle Discussion List <oracle-l_at_freelists.org> Sent: Sunday, December 9, 2012 2:43 AM
Subject: Update Statements and Exadata  

All,
Can anybody let me know the difference for the internal mechanism on parallel update and serial update

When I run serial update Oracle can't offload the statement (I assume this is due to dealing with undo)

If I run the statement parallel (no partitioning) it can offload the scanning part.

I would really appreciate if somebody can walk me through the difference between serial and parallel and why serial is no go.

Regards

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Coskan GUNDOGAR

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Received on Sun Dec 09 2012 - 11:09:53 CET