public inbox for [email protected]  

help / color / mirror / Atom feed

From: Koen De Groote <[email protected]>
To: PostgreSQL General <[email protected]>
Subject: Foreign Data Wrapper behavior?
Date: Fri, 11 Oct 2024 13:08:28 +0200
Message-ID: <CAGbX52Eqa25L1afuVq6NWfnMfmwV5m5zpek=whU8=5U-E9unxQ@mail.gmail.com> (raw)

In the release notes for postgres 17 I'm reading:

> The PostgreSQL foreign data wrapper (postgres_fdw), used to execute
queries on remote PostgreSQL instances, can now push EXISTS and IN
subqueries to the remote server for more efficient processing.

I'm confused as to what this means. In older versions, are parts of queries
not sent to the foreign server? Or is this change meant to imply the
sending of only the subqueries, the result of which is then directly used
in pushing the entire query?

Or am I still wrong as to what this means?

I looked at the documentation and there doesn't seem to be any indication
of particular queries not being pushed to the foreign server, so this
wording that "can now push EXISTS and IN subqueries to the remote server"
is confusing.

What am I missing?

Regards,
Koen De Groote

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected]
  Subject: Re: Foreign Data Wrapper behavior?
  In-Reply-To: <CAGbX52Eqa25L1afuVq6NWfnMfmwV5m5zpek=whU8=5U-E9unxQ@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox