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How long will my database upgrade take? Revisited …

I received this question twice within a few days. And I remember that a tiny little while ago I wrote something on the blog about it. But as this “while” is 11 years ago, I came to conclusion to refresh this topic – and write something about How long will my database upgrade take? Revisited …

How long will my database upgrade take? Revisited ...

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Is there a query?

At first, before I go into details, an important fact upfront: There is neither any query nor any tool giving you a rough estimate or precise figure of how long your upgrade will

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Differences between Automatic Statistics Gathering job and GATHER_SCHEMA_STATS

Recently a customer raised a question whether there are differences between the Automatic Statistics Gathering job and a manual creation of stats via the GATHER_SCHEMA_STATS procedure.

The results in performance were quite interesting. Performance after an upgrade from Oracle Database 11.2.0.3 to Oracle Database 11.2.0.4 was not good when the automatic stats job got used. But performance changed significantly to the better when schema stats were created with the downside of taking more resources during the gathering.

Is the Automatic Stats Gathering job enabled?

That question can be answered quite easily. There’s a very good MOS Note:1233203.1 – FAQ: Automatic

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