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alter table ... enable row movement [message #656794] Wed, 19 October 2016 08:50 Go to next message
John Watson
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Just a minor question - does anyone know what enabling row movement actually does? Or how to see if row movement has been enabled for a table? As far as I can tell, it has no real effect at all. It is just that if you don't enable it, some things won't work. Right now, I can think of three cases where it is needed:

A partitioned table, if updating the partitioning key
Before using ALTER TABLE ... SHRINK SPACE
Some uses of DBMS_REDEFINITION

I'm sure there are others, I'ld be interested to know them all.

This is of no practical significance - I'm just curious. Thank you for any insight.

[Updated on: Wed, 19 October 2016 08:51]

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Re: alter table ... enable row movement [message #656801 is a reply to message #656794] Wed, 19 October 2016 09:45 Go to previous messageGo to next message
Michel Cadot
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Quote:
Just a minor question - does anyone know what enabling row movement actually does?
It enables rows to move. Smile
This feature was introduced to forbid some actions because some (I hope old) applications store row ids and access rows with this "key" to be faster.

Quote:
Right now, I can think of three cases where it is needed:
ALTER TABLE MOVE is another one.

Re: alter table ... enable row movement [message #656804 is a reply to message #656801] Wed, 19 October 2016 11:32 Go to previous messageGo to next message
John Watson
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ALTER TABLE MOVE is online now, I just put up a little blog about it Smile
Re: alter table ... enable row movement [message #656825 is a reply to message #656804] Thu, 20 October 2016 02:41 Go to previous messageGo to next message
Michel Cadot
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Forgot to answer the question: "Or how to see if row movement has been enabled for a table?":
%_TABLES.ROW_MOVEMENT

Re: alter table ... enable row movement [message #656844 is a reply to message #656825] Thu, 20 October 2016 06:56 Go to previous message
John Watson
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Registered: January 2010
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Stupid of me. Ta.
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