Re: How number of columns affects performance

On Fri, 1 Aug 2003, Ron Johnson wrote:

> Do all 100 fields *really* all refer to the same *one* entity,
> with no repeating values, etc?

Yes all fields belong to the same entity. I used 100 as an example it may
be something like 60 to 80 fields (there are two tables in question). I
don't formally do 3rd normal form, but for the most part I do most of
the general concepts of normalization.

> If not, then good design says to split the table.

The original data was in Foxpro tables and I have made better normalized
tables in PostgreSQL.


> Also, if it's a high-activity table, but you only rarely need fields
> 60-90, then splitting them out to their own table might be useful
> (especially if some of those fields are large *CHAR or TEXT).

Yes some of the fields are varchars. 5 fields are varchar(22) and 3 longer
(35, 58, 70). The total row length is a little over 400 characters in
Foxpro. In postgreSQL may be less than 300 (ie Foxpro uses ASCII
representation for numbers so to store "1234567" it uses 7 bytes, whereas
in PostgreSQL I can just make it an int and use 4 bytes)