On Sat, 2003-03-29 at 14:47, Christopher Kings-Lynne wrote:
> Hi Andreas,
>
> A few points:
>
> PostgreSQL is rarely going to use an index for a boolean column. The
> reason is that since almost by definition true will occupy 50% of the rows
> and false will occupy 50% (say). In this case, a sequential scan is
> always faster. You would say that the 'selectivity' isn't good enough.
Well, perhaps it should collect statistics, because a "deleted" column
is a prime candidate for a strongly skewed population.
Andreas
