Re: Chained vs. migrated rows - Any easy way to tell the difference?

From: Martin Berger <>
Date: Tue, 28 Oct 2008 21:47:02 +0100
Message-Id: <>


length() and lengthb() only work for varchar2 (itherwise you may hit an implicit conversion let's say from date to varchar2, which will result in totally garbage) . be careful in guessing the correct length of any row.
I struggled about BUG:4549673 / BUG:7295712 where the distinction between chained and migrated rows is vital. The only clear way I got from Oracle support is a block dump and interpreting this (Note: 122020.1 / Note:102989.1
So after all my research I cannot give you a useful solution. We increased PCTFREE to an insane value of > 90% to make sure a migrated row can never happen. (This was ok in this particular case)

sorry, no good news, just some infos.

Martin Berger

> All I found in the Oracle docs was the suggestion to assume they're
> migrated and if the fix doesn't work then that means they were
> really chained ( Note:122020.1).
> I'm considering using length() on all the columns and adding them
> together to find any rows that wouldn’t fit in a block but was
> wondering if there was an easier way. Besides, one of the tables
> (third party app) has a long raw column so there's no easy way to
> get the column length there.


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Received on Tue Oct 28 2008 - 15:47:02 CDT

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