Re: Primary key vs unique index

On Thu, Mar 17, 2011 at 12:51 PM, Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com> wrote:
> On Thu, Mar 17, 2011 at 6:19 AM, Voils, Steven M <steve(at)sensorswitch(dot)com> wrote:
>> Is there a fundamental difference between a primary key and a unique index?
>> Currently we have primary keys on tables that have significant amounts of
>> updates performed on them, as a result the primary key indexes are becoming
>> significantly bloated.  There are other indexes on the tables that also
>> become bloated as a result of this, but these are automatically rebuild
>> periodically by the application (using the concurrently flag) when read
>> usage is expected to be very low.
>
> If you're experiencing bloat, but not deleting huge chunks of your
> table at a time, then you're not vacuuming aggressively enough

Or you're on 8.3 or before and blowing out your free space map.