Re: Horizontal scalability/sharding - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Horizontal scalability/sharding
Date
Msg-id 20150831185947.GB17858@momjian.us
Whole thread Raw
In response to Re: Horizontal scalability/sharding  (Mason S <masonlists@gmail.com>)
List pgsql-hackers
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@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + Everyone has their own god. +



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