DBLINK_FETCH(3) PostgreSQL 15.7 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 15.7 2024 DBLINK_FETCH(3)
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