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Message Posted: Fri, 20 Jul 2012 @ 09:49:45 GMT
If I look at the explain plan for : Select Top 5 * from cedw.mr_report_selected order by column_name; then it says
3) We do an all-AMPs STAT FUNCTION step from cedw.mr_report_selected by way of an all-rows scan with no residual conditions into Spool 5 (Last Use), which is redistributed by hash code to all AMPs. The result rows are put into Spool 1 (all_amps), which is built locally on the AMPs. This step is used to retrieve the TOP 5 rows. The size is estimated with low confidence to be 5 rows (755 bytes).
What does it mean by all-AMPs STAT FUNCTION ?? Can anyone help me in understanding the whole explain plan here.
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