Re: varchar as primary key

On 5/3/07, Matthew Hixson <hixson@poindextrose.org> wrote:
>    Is there a significant performance difference between using int
> primary keys and string primary keys in Postgres?

PostgreSQL uses B-trees for its indexes, insertion time is logarithmic
regardless of the type of the key, but strings have a larger overhead
since they involve character comparisons; (i - j) is a lot faster than
strcmp(i, j). If you do go for strings, I would suggest that the
beginning of the key be statistically distributed as widely as
possible; ie., avoid common prefixes.

Alexander.