Archives of the TeradataForum
Message Posted: Thu, 04 Oct 2001 @ 16:15:31 GMT
| 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.
IA&DSS Team Leader
Information Resource Management
Hudson's Bay Company