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Archives of the TeradataForum
Message Posted: Fri, 14 Mar 2003 @ 17:57:46 GMT
| Subj: | | Re: Deleting from a huge table |
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| From: | | Dennis Calkins |
Anantaraman, Kumaran (K.) wrote:
| | wall time in secs (mload = 75, insert-select = 2160)
AMP CPU (mload = 1686, insert-select = 39067)
Disk I/O (mload = 4305018, insert-select = 14124056) | |
| | The table had 500 mill rows and I was deleting 100 mill (20%) on a WHERE on a non-PI column date column. There are no SIs, and there
were no blocking during the runs. I am using V2R4.1 | |
| | What could explain the above results? | |
Hi,
Insert select has to move the 80% of the rows which are remaining to a new table.
Multiload delete only needs to delete 20% of the rows.
Deleting 100 million rows is faster than writing 400 million rows.
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