Hi Francisco,

 

thanks!

The solution with 

 

(cat q2.sql; ​ psql -h host1 -U user1 -d db1  -f /q1.sql) | psql -h host2 -U 
user2 -d db2

worked! First I have forgotten the semicolon at the end of q2.sql and got an 
error. 

 

Tim

 

Von: Francisco Olarte [mailto:fola...@peoplecall.com] 
Gesendet: Mittwoch, 4. März 2015 15:48
An: Adrian Klaver
Cc: Tim Semmelhaack; pgsql-general@postgresql.org
Betreff: Re: [GENERAL] Copy Data between different databases

 

Hi Adrian:

 

On Wed, Mar 4, 2015 at 1:03 AM, Adrian Klaver <adrian.kla...@aklaver.com 
<mailto:adrian.kla...@aklaver.com> > wrote:

 

​As you pointed, my bet is in the -f case COPY FROM STDIN expects the
data on the file ( otherwise pg_dumps would not work ), but your
sugestion seems to have a problem of double redirection, let me elaborate:


Well according to here, they should be roughly equivalent:

http://www.postgresql.org/docs/9.3/interactive/app-psql.html


​....   Yeah, they should​, I' was not discussing you. I was pointing the SHELL 
line was incorrect, 


 

Trying it showed they where and ended with the same result, the data was not 
copied over:(

 

​Of course, I'll be greatly surprissed if they did. ​

 



If I did this:

psql -h host1 -U user1 -d db1  -f /q1.sql | psql -h host2 -U user2 -d db2 -f -

I saw the stdout from my 'q1.sql' show up at the second command, where it threw 
an error because it was just the data without the COPY .. FROM statement. So 
the second command must eat the stdin before it actually runs q2.sql. Figured 
this would have been an easy fix. In my case for this sort of thing I use 
Python/psycopg2 and its COPY TO/FROM  commands and run it through a buffer. 
Though of late I have starting using Pandas also.

 

​Of course you end up with an error, I would have reported a bug otherwise. And 
also you are not using q2.sql so the result would have been wrong. I did send 
you a form ( what you've nicely quoted back ) :

 


(cat q2.sql; ​ psql -h host1 -U user1 -d db1  -f /q1.sql) | psql -h host2 -U 
user2 -d db2

 

​of putting q2.sql in front ​of the output from q1.sql in the same pipe, even 
with some samples of how this pipes works. Maybe you stopped reading too soon. 
I cannot try it as I do not have q1.sql or q2.sql, but given what I know about 
the reading/writing code of psql ( and that I have made this kinds of things 
before ) it should work. It's a classical shell construct, use a sub-shell ( 
parentheses ) to combine several commands and pipe its output to another one. 
The problem what all the others constructs seem to be trying to do it with a 
pipe of single commands, which is much more difficult. Of course, if the 
problemis due to inadequate shells ( as, say, cmd.exe ) it may need to be done 
in other ways.




Regards.

   Francisco Olarte.

 

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