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histogram [message #344088] Thu, 28 August 2008 14:11 Go to next message
ArvindBhope
Messages: 55
Registered: June 2008
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Hello,


When do we come to a conclusion that the histograms will help us basically?

thanks,
Arvind
Re: histogram [message #344089 is a reply to message #344088] Thu, 28 August 2008 14:14 Go to previous messageGo to next message
BlackSwan
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ArvindBhope wrote on Thu, 28 August 2008 12:11
Hello,


When do we come to a conclusion that the histograms will help us basically?

thanks,
Arvind



When your benchmark tests produce a demonstrable improvement in performance.
Re: histogram [message #344093 is a reply to message #344088] Thu, 28 August 2008 14:30 Go to previous messageGo to next message
Mahesh Rajendran
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Very broadly speaking,
If your data is skewed and
If the said column data is used in your where clause.
>>conclusion that the histograms will help us basically?
Histograms does not magically improve the performance.
It will give the CBO a better picture (more realistic cardinality) to do its job.
Re: histogram [message #344095 is a reply to message #344088] Thu, 28 August 2008 14:37 Go to previous messageGo to next message
ArvindBhope
Messages: 55
Registered: June 2008
Member
thanks Mahesh,
Iam very new to it ...and could get some info on this.

How do i make a histogram?

thanks,
Arvind
Re: histogram [message #344096 is a reply to message #344095] Thu, 28 August 2008 14:41 Go to previous message
Mahesh Rajendran
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http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/stats.htm#i42219
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