Re: Optimization for updating foreign tables in Postgres FDW

On 2015/03/05 21:08, Etsuro Fujita wrote:
> Here is an updated version.

> The EXPLAIN output has also been improved as discussed in [1].

I noticed that the EXPLAIN for a pushed-down update (delete) on 
inheritance childs doubly displays "Foreign Update" ("Foreign Delete"), 
one for ForeignScan and the other for ModifyTable.  Here is an example:

postgres=# explain verbose update parent set c1 = c1;                                  QUERY PLAN
------------------------------------------------------------------------------ Update on public.parent
(cost=0.00..364.54rows=4819 width=10)   Update on public.parent   Foreign Update on public.ft1   Foreign Update on
public.ft2  ->  Seq Scan on public.parent  (cost=0.00..0.00 rows=1 width=10)         Output: parent.c1, parent.ctid
-> Foreign Update on public.ft1  (cost=100.00..182.27 rows=2409 
 
width=10)         Remote SQL: UPDATE public.t1 SET c1 = c1   ->  Foreign Update on public.ft2  (cost=100.00..182.27
rows=2409
 
width=10)         Remote SQL: UPDATE public.t2 SET c1 = c1
(10 rows)

Should we do something?  Suggestions are welcome.

Best regards,
Etsuro Fujita

[1] http://www.postgresql.org/message-id/31942.1410534785@sss.pgh.pa.us