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Message Posted: Wed, 22 Mar 2006 @ 20:30:17 GMT


     
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Subj:   Re: Usage of TOP function
 
From:   Dieter Noeth

Frank.C.Martinez wrote:

  But what about the fact that each AMP will return rows as they become available as well? So rowid X on AMP N may come back before rowid Y on AMP M the first time, but then when AMP N is busy doing other stuff, rowid Y will come in before the other one, 'cause AMP M isn't doing as much as the other AMP? Right?  


Hmmm, don't know, how it's actually implemented...

Maybe just wait until the system is really busy and then:

     .SESSION 10
     .REPEAT 1000
     insert into xxx select top 5001 * from large_table;
     select distinct * from xxx;
     ;-)

At least in the "Single AMP optimization" case it's probably always the same.

Unless it's utilizing "Sync Scan" :-(


Dieter



     
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