Home Page for the TeradataForum
 

Archives of the TeradataForum

Message Posted: Fri, 22 Feb 2002 @ 22:52:30 GMT


     
  <Prev Next>   <<First <Prev
Next>
Last>>
 


Subj:   Re: BTEQ Question
 
From:   Geoffrey Rommel

  Just an observation. At one of my customer sites, we discovered that when you qualify a request and then use SAMPLE, you might get a FTS anyway. In our testing, it would do the FTS when you qualified with a TIMESTAMP column but with other columns it did the quick SAMPLE....  



I don't claim to know much about this point, but my class notes for Physical Database Design (dated 1996) say, rather cryptically, "Do not include TIME in any index.... Indexes with TIME are used for insert only, because exact time is unknown." I think they assume that whenever you use a TIME or TIMESTAMP column in your query, you don't really know the exact time down to the microsecond, so they will ignore that and do a FTS instead.


--wgr



     
  <Prev Next>   <<First <Prev
Next>
Last>>
 
 
 
 
 
 
 
 
 
  
  Top Home Privacy Feedback  
 
 
Copyright for the TeradataForum (TDATA-L), Manta BlueSky    
Copyright 2016 - All Rights Reserved    
Last Modified: 27 Dec 2016