[PERFORM] Does it matters the column order in indexes and constraints creation?

[Arnau]

Hi all,

  I've got a doubt about how to create an index and a primary key. Lets 
say I have the following table:

  CREATE TABLE blacklist
  (
    telephone    VARCHAR(15),
    customer_id    INT4
                 CONSTRAINT fk_blacklist_customerid REFERENCES
                   customers( customer_id ),
    country_id     INT2
                 CONSTRAINT fk_blacklist_countryid REFERENCES
                   countries( country_id ),
                 CONSTRAINT pk_blacklist_cidcustidtel
                   PRIMARY KEY(country_id, customer_id, telephone)
  );

  The country_id column can have maybe 100 - 250 different values.
  The customer_id column can have as much several hundred values (less 
than 1000).
  The telephone is where all will be different.

  So my doubt is, in terms of performance makes any difference the 
order of the primary key fields? The same in the index definition? I 
have checked the postgresql documentation I haven't been able to find 
anything about.

Thanks
--
Arnau

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