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Re: Please a parameter to disable undo, like _disable_logging

From: Tanel Põder <tanel.poder.003_at_mail.ee>
Date: Thu, 7 Oct 2004 00:55:28 +0300
Message-ID: <050401c4abef$31b670f0$39bd9fd9@porgand>


> Or I'm wrong.

Yep, you've made the wrong conclusion.

The reasons why you can't see nor modify a table after you've done a direct path insert into it, is that Oracle doesn't advance high water mark to the end of newly formatted blocks before commit (this allows efficient "undo" for this transaction by just not moving hwm to new location during rollback. Things get more complex with indexes, though).

So, if your session would be allowed to see a table right after direct path insert, we could get wrong query results because full table scan for example only scans up to current HWM and knows nothing about the newly formatted blocks above it...

Tanel.

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Received on Wed Oct 06 2004 - 16:51:04 CDT

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