Re: Horizontal scalability/sharding

On Mon, Aug 31, 2015 at 02:48:31PM -0400, Mason S wrote:
> I assume that future work around PG sharding probably would be more likely to
> be accepted with the FDW approach. One could perhaps work on pushing down
> joins, aggregates and order by, then look at any optimizations gained if code
> is moved outside of FDW.  It would make sense if some kind of generic
> optimization for foreign tables for SQL-based sources could be leveraged across
> all databases, rather than having to re-implement for each FDW.
>
> There are different approaches and related features that may need to be
> improved.
>
> Do we want multiple copies of shards, like the pg_shard approach? Or keep
> things simpler and leave it up to the DBA to add standbys? 

I agree with all of the above.

> Do we want to leverage table inheritance? If so, we may want to spend time
> improving performance for when the number of shards becomes large with what
> currently exists. If using table inheritance, we could add the ability to
> specify what node (er, foreign server) the subtable lives on. We could create
> top level sharding expressions that allow these to be implicitly created.
>
> Should we allow arbitrary expressions for shards, not just range, list and
> hash?
>
> Maybe the most community-acceptable approach would look something like

I think everyone agrees that our current partitioning setup is just too
verbose and error-prone for users, and needs a simpler interface, and
one that can be better optimized internally. I assume FDW-based
sharding will benefit from that work as well.

--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com

+ Everyone has their own god. +