Re: exp: why have statistics=estimate option?

From: Thomas J. Kyte <tkyte_at_us.oracle.com>
Date: 1996/12/30
Message-ID: <32c819d6.19351395@dcsun4>#1/1

because stats collection is more then counting rows....

it is counting discrete values within a column (lots of sort space needed for near unique columns)

it is finding high/low key values (ranges)

in later versions it is creating histograms of data distribution

and so on....

On Mon, 30 Dec 1996 18:45:32 GMT, chuckh_at_dvol.com (Chuck Hamilton) wrote:

>Maybe this is a dumb question, but why even have the
>'statistics=estimate' option in the export utility? When a table gets
>imported, the _exact_ number of rows imported is already available.
>Why not just use that number to populate DBA_TABLES.NUM_ROWS instead
>of going through the time consuming process of issuing an ANALYZE
>TABLE command?
>--
>Chuck Hamilton
>chuckh_at_dvol.com
>
>This message delivered by electronic sled dogs. WOOF!

Thomas Kyte
Oracle Government
tkyte_at_us.oracle.com                          

http://govt.us.oracle.com

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statements and opinions are mine and do not necessarily reflect the opinions of Oracle Corporation Received on Mon Dec 30 1996 - 00:00:00 CST