RE: How long are statistics good for

From: Christopher Spence <cspence_at_FuelSpot.com>
Date: Tue, 23 Oct 2001 11:05:17 -0700
Message-ID: <F001.003B261B.20011023112020@fatcity.com>

Statistics become old after a single change is made to the object.

Granted adding a single row to a 1 Million row table isn't going to effect much. But adding 100,000 rows will. So where do you draw the line?

I really don't know. But 5%-10% is generally a good measure. Sometimes more sometimes less depending on the size.

"Do not criticize someone until you walked a mile in their shoes, that way when you criticize them, you are a mile a way and have their shoes."

Christopher R. Spence
Oracle DBA
Phone: (978) 322-5744
Fax: (707) 885-2275

Fuelspot
73 Princeton Street
North, Chelmsford 01863

-----Original Message-----
Sent: Tuesday, October 23, 2001 2:00 PM
To: Multiple recipients of list ORACLE-L

We have a data-warehouse that is a combination of Snapshots and table-builds based on the snapshots.

The table builds run at 4:30 am, scripts are setup to start the snapshots at 7:00am and end
at 9:00pm. At 6:30 am a script performs an analyze on ALL (except sys and system) tables in
the database.

If the snapshots have been running all day, should I run an analyze before I do the table builds?
as opposed to after ?

At what point do the statistics on a table become no good ? when a new row is added ?

Thanks

Darren

Darren Browett P.Eng                                            This message
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Author: Browett, Darren
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Author: Christopher Spence
INET: cspence_at_FuelSpot.com

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