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Home -> Community -> Mailing Lists -> Oracle-L -> RE: wait event puzzler
For the record, 'db file sequential read' isn't ALWAYS a single-block read.
There are cases in which you can see 'db file sequential read' events with
p3>1. It happens (well, happened) when the kernel reads from a data file
directly into a user's non-shared process space (not the SGA). It used to
happen in Oracle7.3 when reading sort segments from disk into a PGS.
Nowadays, these reads are done with the event 'direct path read'.
It is true that 'db file scattered read' will never have p3=1.
Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com
Upcoming events:
- Hotsos Clinic 101 in Dallas, Washington, Denver, Sydney - Hotsos Symposium 2004, March 7-10 Dallas - Visit www.hotsos.com for schedule details...
-----Original Message-----
Wolfgang Breitling
Sent: Wednesday, June 11, 2003 3:55 PM
To: Multiple recipients of list ORACLE-L
Yes, 'db file sequential read' is always a single block read. It is 'db file scattered read' which is <= DB_FILE_MULTIBLOCK_READ_COUNT
At 10:35 AM 6/11/2003 -0800, you wrote:
>A SINGLE block? I was convinced that it was <=
DB_FILE_MULTIBLOCK_READ_COUNT
>blocks.
>Are you sure?
>
>Mladen Gogala
>Oracle DBA
>Phone:(203) 459-6855
>Email:[EMAIL PROTECTED]
>
>
>-----Original Message-----
>Sent: Wednesday, June 11, 2003 2:19 PM
>To: Multiple recipients of list ORACLE-L
>
>
>Dennis:
>
>THe event 'db file sequential read' is NOT always an INDEX Scan. It is
>just a single block read which TYPICALLY happens during an INDEX scan.
>The word 'TYPICALLY' is the key here.
>
>
>
>Best Regards,
>K Gopalakrishnan
Wolfgang Breitling
Oracle7, 8, 8i, 9i OCP DBA
Centrex Consulting Corporation
http://www.centrexcc.com
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Wolfgang Breitling INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Cary Millsap INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).Received on Sun Jun 15 2003 - 00:38:55 CDT
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