Hi Bruce,

Sumedh from Citus Data here.

> August, 2015:  While speaking at SFPUG, Citus Data approached me about joining
the FDW sharding team.  They have been invited to the September 1 meeting,
as have the XC and XL people.

I'd like to add a clarification. We already tried the FDW APIs for pg_shard
two years ago and failed. We figured sharing our learnings could contribute
to the technical discussion and that's why we wanted to be in the call.

Ozgun summarized our technical learnings in this design document:
https://goo.gl/vJWF85

In the document, we focused on one of the four learnings we had with FDW
APIs. For us, we switched to the hook API based approach, and things went
smoothly from there.

Best,
Sumedh

On Sat, Aug 29, 2015 at 7:17 PM, Bruce Momjian <br...@momjian.us> wrote:

> I have recently increased my public statements about the idea of adding
> horizontal scaling/sharding to Postgres. I wanted to share with hackers
> a timeline of how we got here, and where I think we are going in the
> short term:
>
> 2012-2013:  As part of writing my scaling talk
> (http://momjian.us/main/presentations/overview.html#scaling), studying
> Oracle RAC, and talking to users, it became clear that an XC-like
> architecture (sharding) was the only architecture that was going to allow
> for write scaling.
>
> Users and conference attendees I talked to were increasingly concerned
> about the ability of Postgres to scale for high write volumes.  They didn't
> necessarily need that scale now, but they needed to know they could get
> it if they wanted it, and wouldn't need to switch to a new database in
> the future.  This is similar to wanting a car that can get you on a highway
> on-ramp fast --- even if you don't need it, you want to know it is there.
>
> 2014:  I started to shop around the idea that we could use FDWs,
> parallelism, and a transaction/snapshot manager to get XC features
> as built-in to Postgres.  (I don't remember where the original idea
> came from.)  It was clear that having separate forks of the source code
> in XC and XL was never going to achieve critical mass --- there just
> aren't enough people who need high right scale right now, and the fork
> maintenance overhead is a huge burden.
>
> I realized that we would never get community acceptance to dump the XC
> (or XL) code needed for sharding into community Postgres, but with FDWs,
> we could add the features as _part_ of improving FDWs, which would benefit
> FDWs _and_ would be useful for sharding.  (We already see some of those
> FDW features in 9.5.)
>
> October, 2014:  EDB and NTT started working together in the community
> to start improving FDWs as a basis for an FDW-based sharding solution.
> Many of the 9.5 FDW improvements that also benefit sharding were developed
> by a combined EDB/NTT team.  The features improved FDWs independent of
> sharding, so they didn't need community buy-in on sharding to get them
> accepted.
>
> June, 2015:  I attended the PGCon sharding unconference session and
> there was a huge discussion about where we should go with sharding.
> I think the big take-away was that most people liked the FDW approach,
> but had business/customer reasons for wanting to work on XC or XL because
> those would be production-ready faster.
>
> July, 2015:  Oleg Bartunov and his new company Postgres Professional (PP)
> started to think about joining the FDW approach, rather than working on
> XL, as they had stated at PGCon in June.  A joint NTT/EDB/PP phone-in
> meeting is scheduled for September 1.
>
> August, 2015:  While speaking at SFPUG, Citus Data approached me about
> joining the FDW sharding team.  They have been invited to the September
> 1 meeting, as have the XC and XL people.
>
> October, 2015:  EDB is sponsoring a free 3-hour summit about FDW sharding
> at the PG-EU conference in Vienna.   Everyone is invited, but it is hoped
> most of the September 1 folks can attend.
>
> February, 2016:  Oleg is planning a similar meeting at their February
> Moscow conference.
>
> Anyway, I wanted to explain the work that has been happening around
> sharding.  As things move forward, I am increasingly convinced that write
> scaling will be needed soon, that the XC approach is the only reasonable
> way to do it, and that FDWs are the cleanest way to get it into community
> Postgres.
>
> --
>   Bruce Momjian  <br...@momjian.us>        http://momjian.us
>   EnterpriseDB                             http://enterprisedb.com
>
>   + Everyone has their own god. +
>
>
> --
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>



-- 
*Sumedh Pathak*
Citus Data
650.422.9797
sum...@citusdata.com

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