dblink_fetch - Man Page

dblink_fetch(text cursorname, int howmany [, bool fail_on_error]) returns setof record
dblink_fetch(text connname, text cursorname, int howmany [, bool fail_on_error]) returns setof record

dblink_fetch fetches rows from a cursor previously established by dblink_open​.

connname

Name of the connection to use; omit this parameter to use the unnamed connection​.

cursorname

The name of the cursor to fetch from​.

howmany

The maximum number of rows to retrieve​. The next howmany rows are fetched, starting at the current cursor position, moving forward​. Once the cursor has reached its end, no more rows are produced​.

fail_on_error

If true (the default when omitted) then an error thrown on the remote side of the connection causes an error to also be thrown locally​. If false, the remote error is locally reported as a NOTICE, and the function returns no rows​.

The function returns the row(s) fetched from the cursor​. To use this function, you will need to specify the expected set of columns, as previously discussed for dblink​.

On a mismatch between the number of return columns specified in the FROM clause, and the actual number of columns returned by the remote cursor, an error will be thrown​. In this event, the remote cursor is still advanced by as many rows as it would have been if the error had not occurred​. The same is true for any other error occurring in the local query after the remote FETCH has been done​.

SELECT dblink_connect('dbname=postgres options=-csearch_path=');
 dblink_connect
----------------
 OK
(1 row)

SELECT dblink_open('foo', 'select proname, prosrc from pg_proc where proname like ''bytea%''');
 dblink_open
-------------
 OK
(1 row)

SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
 funcname |  source
----------+----------
 byteacat | byteacat
 byteacmp | byteacmp
 byteaeq  | byteaeq
 byteage  | byteage
 byteagt  | byteagt
(5 rows)

SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
 funcname  |  source
-----------+-----------
 byteain   | byteain
 byteale   | byteale
 bytealike | bytealike
 bytealt   | bytealt
 byteane   | byteane
(5 rows)

SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
  funcname  |   source
------------+------------
 byteanlike | byteanlike
 byteaout   | byteaout
(2 rows)

SELECT * FROM dblink_fetch('foo', 5) AS (funcname name, source text);
 funcname | source
----------+--------
(0 rows)