Re: "direct path read" and "db file sequential read" used for full table scans in 11g

  • From: Sayan Malakshinov <xt.and.r@xxxxxxxxx>
  • To: Brandon.Allen@xxxxxxxxxxx
  • Date: Fri, 31 Aug 2012 01:30:19 +0400

Hi, Brandon.

You may be interested in these articles:
http://hoopercharles.wordpress.com/2010/06/17/_small_table_threshold-parameter-and-buffer-cache-what-is-wrong-with-this-quote/
http://afatkulin.blogspot.com/2012/07/serial-direct-path-reads-in-11gr2-and.html


On Fri, Aug 31, 2012 at 1:09 AM, Allen, Brandon
<Brandon.Allen@xxxxxxxxxxx> wrote:
> I found the answer to question #3 - apparently it's a new feature called 
> "In-Memory Parallel Execution" as documented at the links below.  I'm still 
> looking for answers on #1 and 2 though if anyone has any ideas.
> http://docs.oracle.com/cd/E11882_01/server.112/e25554/px.htm
>
> http://docs.oracle.com/cd/E11882_01/server.112/e25523/parallel002.htm
>
>
> From: Allen, Brandon
>
>
>
> 1)      How can I force production to use the direct path reads?
>
> 2)      Why is it using "db file sequential read" for a full table scan 
> instead of "db file scattered read"?
>
> 3)      I also tried setting PARALLEL to 2 on the table in question and it 
> did force Oracle to use a parallel execution plan, but it still used "db file 
> sequential read" instead of "direct path read" - any idea why this could be?
>
>
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-- 
Best regards,
Sayan Malakshinov
Senior oracle developer
PromSvayzBank
Tel: +7 903 207-1576
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