Horton

Re: WIP: Join push-down for foreign tables

Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>

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From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Shigeru Hanada <shigeru.hanada@gmail.com>, Kohei KaiGai <kaigai@kaigai.gr.jp>, Robert Haas <robertmhaas@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2012-01-05T10:58:09Z
Lists: pgsql-hackers 
On 03.12.2011 01:05, Tom Lane wrote:
> Heikki Linnakangas<heikki.linnakangas@enterprisedb.com>  writes:
>> Hmm, so you're saying that the FDW function needs to be able to return
>> multiple paths for a single joinrel. Fair enough, and that's not
>> specific to remote joins. Even a single-table foreign scan could be
>> implemented differently depending on whether you prefer fast-start or
>> cheapest total.
>
> ... or ordered vs unordered, etc.  Yeah, good point, we already got this
> wrong with the PlanForeignScan API.  Good thing we didn't promise that
> would be stable.

This discussion withered down here...

I think the advice to Shigeru-san is to work on the API. We didn't reach 
a consensus on what exactly it should look like, but at least you need 
to be able to return multiple paths for a single joinrel, and should 
look at fixing the PlanForeignScan API to allow that too.

-- 
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com