po 19. 10. 2020 v 20:18 odesílatel Igor Korot <ikorot01@gmail.com> napsal:
Hi, Pavel,
On Mon, Oct 19, 2020 at 12:51 PM Pavel Stehule <pavel.stehule@gmail.com> wrote: > > Hi > > po 19. 10. 2020 v 19:40 odesílatel Igor Korot <ikorot01@gmail.com> napsal: >> >> Hi, >> IIUC, PostgreSQL does not support attaching a database to an existing >> connection. >> However I was told that I can use this: >> https://www.postgresql.org/docs/9.3/postgres-fdw.html. >> >> Is it the same thing? Why there is no simple >> >> ATTACH <db> AS <dbname> >> > > It is a different thing - postgresql_fdw does nested connect - it uses client-server protocol. > > For postgres connect and sql engine process is one entity - and engine is written without a possibility to reconnect to another database.
So if I understand correctly the postgresql_fdw is creating a second connection and uses it as kind of "virtualizing mechanism" in order to give access to the second database.
yes - it does new connect to somewhere (local or remote server, but mechanism is absolutely same)