Re: Fwd: [PATCHES] Auto Partitioning Patch - WIP version 1

On Thu, Nov 27, 2008 at 8:07 AM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> The semantics of PARTITION ON (<expr>) are unclear to me. I was
> thinking maybe it would make sense to do something like:
>
> CREATE PARTITION <name> ON <table> WHERE <expr>
>

At first look seems nice but s Gregory said the ideal would be to
identify the key partition.

>
> I like the idea of using table inheritance as a foundation for this
> feature, but I think it's not going to be very useful for real-world
> applications without cross-table indexes. Suppose for example that I
> have five years worth of data (thus, 60 partitions) and each
> transaction has a unique identifier of some sort that is unrelated to
> the date. It's bad enough that a query like this has to check every
> partition:
>

you haven't. the WHERE clause in your hipotetical CREATE PARTITION
should create a check constraint on the child (inherited) table and if
you have constraint_exclusion to on you will check just the
partition(s) that match with the check constraint.

>
> What's even worse (at least IMHO) is that there's no way to use
> transaction (uuid) as a reference for a foreign key.
>

not directly, but you always can create a trigger instead of the
foreign key constraint...
mmm...the docs says that there is no good workaround, what about
mention a trigger?

--
Atentamente,
Jaime Casanova
Soporte y capacitación de PostgreSQL
Asesoría y desarrollo de sistemas
Guayaquil - Ecuador
Cel. +59387171157