Re: On partitioning

On Wed, Dec 03, 2014 at 10:00:26AM -0300, Alvaro Herrera wrote:
> Amit Langote wrote:
>
> > From: Robert Haas [mailto:robertmhaas(at)gmail(dot)com]
>
> > > What is an overflow partition and why do we want that?
> >
> > That would be a default partition. That is, where the tuples that
> > don't belong elsewhere (other defined partitions) go. VALUES clause of
> > the definition for such a partition would look like:
> >
> > (a range partition) ... VALUES LESS THAN MAXVALUE
> > (a list partition) ... VALUES DEFAULT
> >
> > There has been discussion about whether there shouldn't be such a
> > place for tuples to go. That is, it should generate an error if a
> > tuple can't go anywhere (or support auto-creating a new one like in
> > interval partitioning?)
>
> In my design I initially had overflow partitions too, because I
> inherited the idea from Itagaki Takahiro's patch. Eventually I realized
> that it's a useless concept, because you can always have leftmost and
> rightmost partitions, which are just regular partitions (except they
> don't have a "low key", resp. "high key"). If you don't define
> unbounded partitions at either side, it's fine, you just raise an error
> whenever the user tries to insert a value for which there is no
> partition.
>
Hi,

Maybe I am not clear on the concept of an overflow partition, but I
thought that it functioned to catch any record that did not fit the
partitioning scheme. You end of range with out a "low key" or "high
key" would only catch problems in those areas. If you partitioned on
work days of the week, you should not have anything on Saturday/Sunday.
How would that work? You would want to catch anything that was not a
weekday in the overflow.

Regards,
Ken