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

  • From: Alex Fatkulin <afatkulin@xxxxxxxxx>
  • To: "Brandon.Allen@xxxxxxxxxxx" <Brandon.Allen@xxxxxxxxxxx>
  • Date: Thu, 30 Aug 2012 21:25:38 -0400

From the events it looks like direct path read did happen - you can see
both object level checkpoint as well as direct path read events. What's
your DBFMRC set to? And what's your SQL*Plus arraysize set to?
Last, if you look into raw trace - are db file sequential read blocks
indeed belong to the table?



>
> Plan and wait events from tkprof:
> --------------------------------
>
> Number of plan statistics captured: 1
>
> Rows (1st) Rows (avg) Rows (max)  Row Source Operation
> ---------- ---------- ----------
>  ---------------------------------------------------
>     600815     600815     600815  SORT ORDER BY (cr=1352370 pr=180699
> pw=24956 time=777998 us cost=69947 size=199593540 card=599380)
>     600815     600815     600815   TABLE ACCESS FULL T_TRIWORKTASK
> (cr=1352370 pr=155743 pw=0 time=96932776 us cost=27251 size=199593540
> card=599380)
>
>
> Elapsed times include waiting on following events:
>   Event waited on                             Times   Max. Wait  Total
> Waited
>   ----------------------------------------   Waited  ----------
>  ------------
>   SQL*Net message to client                   40056        0.00
>  0.02
>   db file sequential read                     32667        0.02
> 74.75
>   reliable message                                1        0.00
>  0.00
>   enq: KO - fast object checkpoint                1        0.01
>  0.01
>   db file scattered read                          1        0.01
>  0.01
>   direct path read                             1798        0.01
>  5.29
>   direct path write temp                        807        0.02
>  1.53
>   asynch descriptor resize                        3        0.00
>  0.00
>   direct path read temp                         346        0.08
>  1.19
>   SQL*Net message from client                 40056       29.28
>  311.98
>
>
>
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-- 
Alex Fatkulin,
http://afatkulin.blogspot.com

Enkitec,
http://www.enkitec.com


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