OraFAQ Forum: Performance Tuning

Home » RDBMS Server » Performance Tuning » histogram

Show: Today's Messages :: Polls :: Message Navigator
E-mail to friend

histogram [message #344088]

Thu, 28 August 2008 14:11

ArvindBhope
Messages: 55
Registered: June 2008

Member

Hello,

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

thanks,
Arvind

Report message to a moderator

Re: histogram [message #344089 is a reply to message #344088]

Thu, 28 August 2008 14:14

BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal

Senior Member

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.

Report message to a moderator

Re: histogram [message #344093 is a reply to message #344088]

Thu, 28 August 2008 14:30

Mahesh Rajendran
Messages: 10708
Registered: March 2002
Location: oracleDocoVille

Senior Member
Account Moderator

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.

Report message to a moderator