DBLINK_FETCH(3)          PostgreSQL 16.2 Documentation         DBLINK_FETCH(3)

NAME
       dblink_fetch - returns rows from an open cursor in a remote database

SYNOPSIS
       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

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

ARGUMENTS
       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.

RETURN VALUE
       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.

NOTES
       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.

EXAMPLES
           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)

PostgreSQL 16.2                      2024                      DBLINK_FETCH(3)