FreeLists / oracle-l / Re: Column order in indices (oracle 9.2)

[genegurevich@xxxxxxxxxxxxxxxxxxxxx]

Goran,

In my case I don't have any range conditions. My query is select * from
table where column='zzz';

thank you

Gene Gurevich



                                                                           
             "goran                                                        
             bogdanovic"                                                   
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             m>                        genegurevich@xxxxxxxxxxxxxxxxxxxxx  
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             08/01/2006 08:03          sac@xxxxxxxxxxxxx, oracle-l         
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                                                                   Subject 
                                       Re: Column order in indices (oracle 
                                       9.2)                                
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           
                                                                           




Pay also attention if some of those columns has been used in the where
clause with a range condition.
If such, put this column(s) at the end of the index. The reason why, you
can find in the book of J.Lewis.
CBO walk the mysterious ways :-)

On 8/1/06, Schultz, Charles <sac@xxxxxxxxxxxxx> wrote:
  The column order does matter, but Oracle can SKIP SCAN an index in the
  situation you talk about. To determine exactly what is going on, you
  should at least get an explain plan of your sql. I imagine there are
  other factors involved.

  -----Original Message-----
  From: oracle-l-bounce@xxxxxxxxxxxxx
  [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of
  genegurevich@xxxxxxxxxxxxxxxxxxxxx
  Sent: Tuesday, August 01, 2006 7:44 AM
  To: oracle-l
  Subject: Column order in indices (oracle 9.2)

  Hi everybody:

  I remember reading that in Oracle 9.2 and higher the order of the
  columns in an index does not matter.
  That is oracle will be able to quickly search on a column even if it is
  not a leading one. I have a table with a primary key consisting of three
  columns. When a table is queried based on the third column, the data
  start coming out immediately, but when I use the second column the query
  just sits there.
  Is that an expected behavior? Did I misunderstood something about the
  column order?

  thanks for any insight

  Gene Gurevich


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