Re: Foreign Data Wrapper Handler

The first pass thru https://www.postgresql.org/docs/12/fdwhandler.html 
does not tell me what I think I need to know, but I will digest this 
more thoroughly. Maybe I need to understand more of the lingo re: 
foreign data wrappers. I do understand that all fdw names must be unique 
within a database so if I want to connect to more than one foreign db, I 
need a different name for each connection. I cannot name each fdw 
postgres_fdw. I would like to name the fdws something like: 
dbname_to_foreigndbname.

For example, here are 2 possible fdws:

create foreign data wrapper stp_to_geo;
create foreign data wrapper stp_to_metrics;

That syntax creates the fdw and I can create user mappings but I cannot 
import any foreign schemas into my database. The error message says that 
there is no handler for the fdw. That's where I'm stuck.

BTW, I did try using postgres_fdw as a handler...

create foreign data wrapper stp_to_geo handler postgres_fdw;

...but then I got these errors:
ERROR:  function postgres_fdw() does not exist
ERROR:  foreign-data wrapper "stp_to_geo" does not exist

Looks like I need to study a bit more.

Sue


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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Susan E Hurst
Principal Consultant
Brookhurst Data LLC
Email: susan.hurst@brookhurstdata.com
Mobile: 314-486-3261

On 2020-11-07 14:51, Adrian Klaver wrote:
> On 11/7/20 12:44 PM, Susan Hurst wrote:
>> Can anyone recommend a good online resource for learning how to set up 
>> a foreign data wrapper using a custom fdw name?  It seems the trick is 
>> to use a handler to make it work but so far the search results have 
>> been elusive for creating a fdw with a successful outcome.
> 
> Have you gone through this?:
> 
> https://www.postgresql.org/docs/12/fdwhandler.html
> 
> Also can we get a definition of 'custom fdw name'?
> 
> 
>> 
>> I'm using 'PostgreSQL 11.8 on amd64-portbld-freebsd12.1, compiled by 
>> FreeBSD clang version 8.0.1 (tags/RELEASE_801/final 366581) (based on 
>> LLVM 8.0.1), 64-bit'
>> 
>> Thanks for your help!
>> 
>> Sue
>>