dblink_send_query — sends an async query to a remote database
dblink_send_query(text connname, text sql) returns int
dblink_send_query sends a query to be executed
asynchronously, that is, without immediately waiting for the result.
There must not be an async query already in progress on the
connection.
After successfully dispatching an async query, completion status
can be checked with dblink_is_busy, and the results
are ultimately collected with dblink_get_result.
It is also possible to attempt to cancel an active async query
using dblink_cancel_query.
connnameName of the connection to use.
sql
The SQL statement that you wish to execute in the remote database,
for example select * from pg_class.
Returns 1 if the query was successfully dispatched, 0 otherwise.
SELECT dblink_send_query('dtest1', 'SELECT * FROM foo WHERE f1 < 3');