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Message Posted: Thu, 31 Jul 2008 @ 15:55:29 GMT


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Subj:		Query man Teradata EXPLAIN interpretation

From:		Derwojed, Olaf

I am sure that it is pretty simple, soo please help me understand something in here.

excerpt from EXPLAIN:

`Explanation --------------------------------------------------`
	`37)`	`We do an all-AMPs RETRIEVE step from Spool 40 (Last Use) by way of an all-rows scan into Spool 21 (all_amps), which is redistributed by hash code to all AMPs. Then we do a SORT to order Spool 21 by the sort key in spool field1 eliminating duplicate rows. The size of Spool 21 is estimated with no confidence to be 4,184,621 rows. The estimated time for this step is 20.07 seconds.`
	`38)`	`Finally, we send out an END TRANSACTION step to all AMPs involved in processing the request.`
	`->`	`The contents of Spool 21 are sent back to the user as the result of statement 1. No rows are returned to the user as the result of statement 2. The total estimated time is 3 minutes and 55 seconds.`

???????????

`Explanation --------------------------------------------------`
	`->`	`The contents of Spool 21 are sent back to the user as the result of statement 1. No rows are returned to the user as the result of statement 2.`

I am trying to identify what does it mean and where do I find this "statement 2"

Because despite of the same thing for similar query I managed to pulled data.

Best Regards

Olaf


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