centos man page for dblink_get_result

DBLINK_GET_RESULT(3)					  PostgreSQL 9.2.7 Documentation				      DBLINK_GET_RESULT(3)

NAME
       dblink_get_result - gets an async query result

SYNOPSIS
       dblink_get_result(text connname [, bool fail_on_error]) returns setof record

DESCRIPTION
       dblink_get_result collects the results of an asynchronous query previously sent with dblink_send_query. If the query is not already
       completed, dblink_get_result will wait until it is.

ARGUMENTS
       conname
	   Name of the connection to use.

       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
       For an async query (that is, a SQL statement returning rows), the function returns the row(s) produced by the query. To use this function,
       you will need to specify the expected set of columns, as previously discussed for dblink.

       For an async command (that is, a SQL statement not returning rows), the function returns a single row with a single text column containing
       the command's status string. It is still necessary to specify that the result will have a single text column in the calling FROM clause.

NOTES
       This function must be called if dblink_send_query returned 1. It must be called once for each query sent, and one additional time to obtain
       an empty set result, before the connection can be used again.

       When using dblink_send_query and dblink_get_result, dblink fetches the entire remote query result before returning any of it to the local
       query processor. If the query returns a large number of rows, this can result in transient memory bloat in the local session. It may be
       better to open such a query as a cursor with dblink_open and then fetch a manageable number of rows at a time. Alternatively, use plain
       dblink(), which avoids memory bloat by spooling large result sets to disk.

EXAMPLES
	   contrib_regression=# SELECT dblink_connect('dtest1', 'dbname=contrib_regression');
	    dblink_connect
	   ----------------
	    OK
	   (1 row)

	   contrib_regression=# SELECT * FROM
	   contrib_regression-# dblink_send_query('dtest1', 'select * from foo where f1 < 3') AS t1;
	    t1
	   ----
	     1
	   (1 row)

	   contrib_regression=# SELECT * FROM dblink_get_result('dtest1') AS t1(f1 int, f2 text, f3 text[]);
	    f1 | f2 |	  f3
	   ----+----+------------
	     0 | a  | {a0,b0,c0}
	     1 | b  | {a1,b1,c1}
	     2 | c  | {a2,b2,c2}
	   (3 rows)

	   contrib_regression=# SELECT * FROM dblink_get_result('dtest1') AS t1(f1 int, f2 text, f3 text[]);
	    f1 | f2 | f3
	   ----+----+----
	   (0 rows)

	   contrib_regression=# SELECT * FROM
	   contrib_regression-# dblink_send_query('dtest1', 'select * from foo where f1 < 3; select * from foo where f1 > 6') AS t1;
	    t1
	   ----
	     1
	   (1 row)

	   contrib_regression=# SELECT * FROM dblink_get_result('dtest1') AS t1(f1 int, f2 text, f3 text[]);
	    f1 | f2 |	  f3
	   ----+----+------------
	     0 | a  | {a0,b0,c0}
	     1 | b  | {a1,b1,c1}
	     2 | c  | {a2,b2,c2}
	   (3 rows)

	   contrib_regression=# SELECT * FROM dblink_get_result('dtest1') AS t1(f1 int, f2 text, f3 text[]);
	    f1 | f2 |	   f3
	   ----+----+---------------
	     7 | h  | {a7,b7,c7}
	     8 | i  | {a8,b8,c8}
	     9 | j  | {a9,b9,c9}
	    10 | k  | {a10,b10,c10}
	   (4 rows)

	   contrib_regression=# SELECT * FROM dblink_get_result('dtest1') AS t1(f1 int, f2 text, f3 text[]);
	    f1 | f2 | f3
	   ----+----+----
	   (0 rows)

PostgreSQL 9.2.7						    2014-02-17						      DBLINK_GET_RESULT(3)