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Estimate the size of an index [message #176039]

Tue, 06 June 2006 08:50

agostino_neto
Messages: 180
Registered: July 2005

Senior Member

Hi,
Does anyone know how to estimate the size of an index if we already have data?
If you like to know if there is a rule to estimate the real size needed for datafiles.
Thanks.

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Re: Estimate the size of an index [message #176877 is a reply to message #176039]

Sun, 11 June 2006 01:28

nmacdannald
Messages: 460
Registered: July 2005
Location: Stockton, California - US...

Senior Member

I think it is as simple as
<The size of your Index segments> * <the number of rows * 1.1>
I think there is an esier way, and I could be wrong.

i.e.
index-segment01 Char(4)
index-segment02 Char( Cool

means 12 * (rowcount * 1.1)

if your number of rows is 1000, then (12 * 1000 * 1.1)
or 13200 bits.

There is a little overhead for Oracle pages but not much.

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Re: Estimate the size of an index [message #177964 is a reply to message #176877]

Sun, 18 June 2006 11:51

agostino_neto
Messages: 180
Registered: July 2005

Senior Member

nmacdannald,

Why 12 ?
Should I read index-segment02 Char( Cool

?
What should be the size for number ?
Thanks for your response.

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