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From Oystein.Grov...@Sun.COM (Øystein Grøvlen)
Subject Re: RowLocation lifetime
Date Tue, 15 Nov 2005 14:30:24 GMT
>>>>> "MM" == Mike Matrigali <mikem_app@sbcglobal.net> writes:

    MM> It is only stable while some sort of stable table intent lock is held.
    MM> Rows can move during a compress table operation.

I understand, when a record is moved to another page, its RecordId
will change.  Is this the only case where a RecordId will change?  If
yes, I would think one could solve the problem for insensitive result
sets by invalidating open result sets when an underlying table is
compressed.

Some questions to how compression works:
   - Will RecordIds ever be reused or will the sequence number continue to
     increase?
   - How do you ensure that the old RecordIds are not encountered
     during recovery?  Does the compression include a checkpoint?
   - It seems like the compression heavily depends on that no log
     records are generated during compression.  Do you have any ideas
     of how to make compression on-line?  I guess you would need a
     mapping between new and old RecordIds (i.e., every move would
     have to be logged.)

-- 
Øystein


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