postgres_fdw : disable extended queries

Nicolas Paris wrote:

I have a 9.6 pg instance, and I am trying to link a foreign postgresql database that do not accept
extended queries. (only simple queries https://www.postgresql.org/docs/current/static/protocol.html )

When I run a query against the foreign pg instance thought postres_fdw, it looks like it sends a
transaction containing

DECLARE c1 CURSOR FOR
SELECT customer_id FROM foodmart.customer

-> is there a way to run a simple query with postgres_fdw such:

SELECT customer_id FROM foodmart.customer

No, it is part of the design that cursors are used, so that rows can be
fetched one at a time and concurrent DML statements can be run.

You might consider using dblink.

Yours,
Laurenz Albe

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2016-10-24 10:36 GMT+02:00 Albe Laurenz <laurenz.albe@wien.gv.at>:

Nicolas Paris wrote:

I have a 9.6 pg instance, and I am trying to link a foreign postgresql

database that do not accept

extended queries. (only simple queries https://www.postgresql.org/

docs/current/static/protocol.html )

When I run a query against the foreign pg instance thought postres_fdw,

it looks like it sends a

transaction containing

DECLARE c1 CURSOR FOR
SELECT customer_id FROM foodmart.customer

-> is there a way to run a simple query with postgres_fdw such:

SELECT customer_id FROM foodmart.customer

No, it is part of the design that cursors are used, so that rows can be
fetched one at a time and concurrent DML statements can be run.

​Actually problem is not with the cursor, sorry. Error message says it's
related to a prepared statement.
I am not able to debug it and see what is happening and what is the
prepared statement. ​

You might consider using dblink.

​
Dblink works great, but It seems less flexible (no predicate push down). I
am able to create a view that encapsulate dblink, but all the rows are
fetch each time I use the view.