RE: v$sql.disk_reads versus v$sql.physical_read_requests
- From: "Walker, Jed S" <Jed_Walker@xxxxxxxxxxxxxxxxx>
- To: Tanel Poder <tanel@xxxxxxxxxxxxxx>
- Date: Fri, 7 Jun 2013 17:17:44 +0000
If the customer doesn't have AWR (due to licensing) is there any way to get
this over snapshots of time other than doing it yourself?
From: Walker, Jed S
Sent: Friday, June 07, 2013 11:16 AM
To: 'Tanel Poder'
Cc: oracle-l@xxxxxxxxxxxxx
Subject: RE: v$sql.disk_reads versus v$sql.physical_read_requests
Ah, of course, thank you!
From: tanel@xxxxxxxxxx [mailto:tanel@xxxxxxxxxx] On Behalf Of Tanel Poder
Sent: Friday, June 07, 2013 11:10 AM
To: Tanel Poder
Cc: Walker, Jed S; oracle-l@xxxxxxxxxxxxx
Subject: Re: v$sql.disk_reads versus v$sql.physical_read_requests
the same goes for the "physical read IO requests" and "physical reads"
statistics in v$sesstat/v$sysstat....
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Tanel Poder
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On Fri, Jun 7, 2013 at 8:08 PM, Tanel Poder
<tanel@xxxxxxxxxxxxxx<mailto:tanel@xxxxxxxxxxxxxx>> wrote:
disk_reads is number of blocks read
physical_read_requests is the number of IO requests done
so if all you do is single block reads, the disk_reads = physical_read_requests
but if you also do multiblock reads, then the dist_reads should be bigger
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Tanel Poder
Enkitec (The Exadata Experts)
Training<http://blog.tanelpoder.com/seminar/> |
Troubleshooting<http://blog.tanelpoder.com/> |
Exadata<http://www.amazon.com/Expert-Oracle-Exadata-Apress/dp/1430233923> |
Voicee App<http://voic.ee/>
On Fri, Jun 7, 2013 at 8:03 PM, Walker, Jed S
<Jed_Walker@xxxxxxxxxxxxxxxxx<mailto:Jed_Walker@xxxxxxxxxxxxxxxxx>> wrote:
I was looking over v$sql and noticed it has disk_reads and
physical_read_requests. I couldn't tell from the docs exactly what the
difference is.
I'm guessing disk_reads is the number of disk reads requested, and
physical_read_requests is how many reads were actually required from the disk
(maybe because of diffs in db block size and disk block size?)
Curious if anyone knows for certain?
thanks
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