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Re: [v9.3] writable foreign tables

From: Kohei KaiGai <kaigai(at)kaigai(dot)gr(dot)jp>
To: Atri Sharma <atri(dot)jiit(at)gmail(dot)com>
Cc: Albe Laurenz <laurenz(dot)albe(at)wien(dot)gv(dot)at>, "Alexander Korotkov *EXTERN*" <aekorotkov(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, PgHacker <pgsql-hackers(at)postgresql(dot)org>, Shigeru Hanada <shigeru(dot)hanada(at)gmail(dot)com>
Subject: Re: [v9.3] writable foreign tables
Date: 2012-11-15 17:53:46
Message-ID: CADyhKSWV6mOQ2oD0z1V=HTOY14UCmqqEm0RbDhOS0EWSg9d7bg@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-hackers
The attached patch is just a refreshed version for clean applying to
the latest tree.

As previous version doing, it makes pseudo enhancement on file_fdw
to print something about the supplied tuple on INSERT, UPDATE and
DELETE statement.
Here is one other idea. My GPU acceleration module (PG-Strom)
implements column-oriented data store underlying foreign table.
It might make sense to cut out this portion for proof-of-concept of
writable foreign tables.

Any ideas?

2012/11/8 Atri Sharma <atri(dot)jiit(at)gmail(dot)com>:
>
>
> On 08-Nov-2012, at 13:35, "Albe Laurenz" <laurenz(dot)albe(at)wien(dot)gv(dot)at> wrote:
>
>> Alexander Korotkov wrote:
>>> 2) You wrote that FDW can support or don't support write depending on
>> having corresponding functions.
>>> However it's likely some tables of same FDW could be writable while
>> another are not. I think we should
>>> have some mechanism for FDW telling whether particular table is
>> writable.
>>
>> I think that this would best be handled by a table option,
>> if necessary.
>> That allows maximum flexibility for the design of the FDW.
>> In many cases it might be enough if the foreign data source
>> raises an error on a write request.
>>
>> Yours,
>> Laurenz Albe
>>
>>
>> --
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>
> +1
>
> I agree, we should have a system where if the foreign data source raises an error on write, FDW can raise corresponding error on PostgreSQL side.exposing this as a table option is IMHO a bit risky, and the user may not know whether the foreign data source will accept writes or not.
>
> Atri



-- 
KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp>

Attachment: pgsql-v9.3-writable-fdw-poc.v4.patch
Description: application/octet-stream (46.3 KB)

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