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Message Posted: Tue, 11 Dec 2007 @ 22:43:34 GMT

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Amol ,

I got some information for your question :--

If the update is for a single row a time then the indexes (including the join index) are updated at that time, but only the values in the indexed column (or join index) change. If the index is not impacted by the change, no update takes place to the index.

If you are doing set-level updates then all changes to the index (or join index) will be batched up and performed a block at a time, after the base table updates. With a join index you can see the join index maintenance as a separate step in the plan. With secondary indexes the batched maintenance is performed in the same step as the base table updates, the file system simply puts the changes into a temporary table and applies them in batch.

Hope it helps

Regards

Ganesh Babu P V
Teradata Certified Master

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