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
It is also possible to attempt to cancel an active async query
Name of the connection to use.
The SQL statement that you wish to execute in the remote database, for example select * from pg_class.