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Message Posted: Thu, 04 Oct 2001 @ 16:15:31 GMT

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Subj:   Re: Removing columns
From:   Ruth Fenwick

Insert/Select to an empty table uses block-at-a-time processing with one transient journal entry per AMP and has instantaneous rollback for aborted Insert-Select statements.

An update or a row inserted into a populated table has a corresponding entry in the TJ for every inserted/updated row. A 'write' of the inserted/updated row and of the TJ entry takes place on a row-by-row basis. Should the transaction abort for any reason, all inserts/updates are deleted/updated one row at a time by scanning the TJ for rowids.

Ruth Fenwick
IA&DSS Team Leader
Information Resource Management
Hudson's Bay Company

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