Statistics accuracy
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| Subject: | Statistics accuracy |
| Author: | Lauri, Netherlands |
| Date: | Mar 08, 2010, 185 days ago |
| Os info: | All |
| Oracle info: | 10gR2 |
| Message: | Hi,
Statistics are re-initialized each time the instance is restarted. If I modify the value of pga_aggregate_target, should the instance be restarted to reflect the current statistics (in this situation the values of the pga advisor)? Kind Regards. |
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| Subject: | Re: Statistics accuracy |
| Author: | Michel Cadot, France |
| Date: | Mar 08, 2010, 185 days ago |
| Message: |
It depends if you use spfile or init.ora. Some of the latest values have been written in spfile but surely not v$pgastat. Regards Michel |
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| Subject: | Re-Statistics accuracy |
| Author: | Lauri, Netherlands |
| Date: | Mar 08, 2010, 185 days ago |
| Message: | Hi Michel,
Thanks. I use a spfile. Does this mean that I should restart the instance to have accurate values in v$pgastat? Kind Regards. |
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| Subject: | Re: Re-Statistics accuracy |
| Author: | Michel Cadot, France |
| Date: | Mar 08, 2010, 185 days ago |
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| Message: |
No, as I said v$pgastat is not in spfile. If you restart the instance, you also restart instance statistics from 0 and Oracle has to learn again what is your activity. Regards Michel |
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| Subject: | Re: Re-Statistics accuracy |
| Author: | Philip Wisse, Netherlands |
| Date: | Mar 08, 2010, 185 days ago |
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| Message: | Hi Lauri,
Instance bouncing is not needed: Base statistics for this view are reset at instance startup and when the value of the PGA_AGGREGATE_TARGET initialization parameter is dynamically modified. http://youngcow.net/doc/oracle10g/server.102/b14237/dynviews_2015.htm Regards, Philip |
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| Subject: | Re: Re-Statistics accuracy |
| Author: | Lauri, Netherlands |
| Date: | Mar 08, 2010, 185 days ago |
| Message: | Hi,
Thanks for these good answers. But I when I am modifying the value of pga_aggregate_target I am also concerned by the statistics in v$pgastat and v$sysstat, and these values are cumulative since instance startup. So, I guess that if I want to see accurate values of statistics for the PGA I would need to restart the instance? Kind Regards. |
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