RE: sreadtim and mreadtim < 1ms
- From: "Allen, Brandon" <Brandon.Allen@xxxxxxxxxxx>
- To: "oracle-l@xxxxxxxxxxxxx" <oracle-l@xxxxxxxxxxxxx>
- Date: Tue, 3 Nov 2009 14:27:16 -0700
There seems to be some confusion about what I was asking in my original post -
I already understand why I'm getting such fast sreadtim and mreadtim values
(from OS caching). I'm just trying to figure out what is the best approach (in
general) for setting the system stats in this scenario:
1) Leaving them unset and using the default stats (ioseektim=10,
iotfrspeed=4096) - this is what I have currently in place
2) Gathering noworkload stats (I get ioseektim=5 and iotfrspeed=35632)
3) Leaving them at their very small values as gathered by
gather_system_stats (sreadtim=.1, mreadtim=.3)
4) Manually setting them higher so the CBO won't ignore them, e.g.
sreadtim=1, mreadtim=3
5) Other options I haven't considered?
I know testing every single one of my application's queries with each different
setting is the only way to know for sure, but I'm just looking for any general
guidelines, rules of thumb, best practices, personal experiences, etc. that
others may have had in this same situation. I figure there must be lots of
people in the same situation with the price & size of RAM these days. I wish I
had 11g with the Real Application Testing license so I could run Database
Capture & Replay with the different stats in place, but this is only 10g
Standard Edition.
Thanks,
Brandon
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