Re: On partitioning

On Fri, Dec 5, 2014 at 10:12 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Fri, Dec 5, 2014 at 2:18 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
wrote:
> > Do we really need to support dml or pg_dump for individual partitions?
>
> I think we do. It's quite reasonable for a DBA (or developer or
> whatever) to want to dump all the data that's in a single partition;
> for example, maybe they have the table partitioned, but also spread
> across several servers. When the data on one machine grows too big,
> they want to dump that partition, move it to a new machine, and drop
> the partition from the old machine. That needs to be easy and
> efficient.
>
> More generally, with inheritance, I've seen the ability to reference
> individual inheritance children be a real life-saver on any number of
> occasions. Now, a new partitioning system that is not as clunky as
> constraint exclusion will hopefully be fast enough that people don't
> need to do it very often any more. But I would be really cautious
> about removing the option. That is the equivalent of installing a new
> fire suppression system and then boarding up the emergency exit.
> Yeah, you *hope* the new fire suppression system is good enough that
> nobody will ever need to go out that way any more. But if you're
> wrong, people will die, so getting rid of it isn't prudent. The
> stakes are not quite so high here, but the principle is the same.
>

Sure, I don't feel we should not provide anyway to take dump
for individual partition but not at level of independent table.
May be something like --table <table_name>
--partition <partition_name>.

In general, I think we should try to avoid exposing that partitions are
individual tables as that might hinder any future enhancement in that
area (example if we someone finds a different and better way to
arrange the partition data, then due to the currently exposed syntax,
we might feel blocked).

With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com