(How) Is it possible to convert tables into foreign tables in Postgres?
<p>We have a large table in our Postgres production database which we want to start "sharding" using foreign tables and inheritance. </p>

<p>The desired architecture will be to have 1 (empty) table that defines the schema and several foreign tables inheriting from the empty "parent" table. (possible with Postgres 9.5)</p>

<p>I found this well written article <a href="https://www.depesz.com/2015/04/02/waiting-for-9-5-allow-foreign-tables-to-participate-in-inheritance/" rel="nofollow">https://www.depesz.com/2015/04/02/waiting-for-9-5-allow-foreign-tables-to-participate-in-inheritance/</a> that explains everything on how to do it from scratch. 
My question is how to reduce the needed migration of data to a minimum. </p>

<p>We have this 100+ GB table now, that should become our first "shard". And in the future we will regulary add new "shards". At some point, the older shards will be moved to another tablespace (on cheaper hardware since they become less important).</p>

<p><strong>My question now:</strong>
Is there a way to "ALTER" an existing table to be a foreign table instead?</p>