Re: Temporary table use and the redo log

From: Jonathan Lewis <>
Date: Mon, 14 Sep 2009 13:00:09 +0100
Message-ID: <>

"Randolf Geist" <> wrote in message On Sep 13, 1:15 pm, "Jonathan Lewis" <> wrote:
> Running on (where the bug is fixed) the insert reports about
> 38 redo records and 32KB of redo size on a global temporary table
> (compared with about 65 and 100KB on a normal table). This is due
> to the way that Oracle can pack multiple changes to a single block
> into a single undo record and redo change vector).
> On, this test reported 2,000 redo records and about 350KB
> or redo generated because that packing optimisation was missing.
> According to my notes, this bug was fixed in (so my comment
> about "most" versions of 9i was wrong) and (The optimisation
> was in 8i).


thanks for the explanation. Your test case seems to refer to conventional DML, does this also apply to direct-path inserts? The test case would generate undo and redo for the primary key index, so I could imagine that it applies there, too, but I'm not sure.

I don't have a pre- version at hand (and no 10.1 either), so cannot test myself at present.


Oracle related stuff blog:

SQLTools++ for Oracle (Open source Oracle GUI for Windows):


The error was only in the code for conventional DML.


Jonathan Lewis

Author: Cost Based Oracle: Fundamentals

The Co-operative Oracle Users' FAQ
Received on Mon Sep 14 2009 - 07:00:09 CDT

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