*** a/contrib/postgres_fdw/connection.c
--- b/contrib/postgres_fdw/connection.c
***************
*** 677,684 **** pgfdw_xact_callback(XactEvent event, void *arg)
  					 * using an asynchronous execution function, the command
  					 * might not have yet completed.  Check to see if a command
  					 * is still being processed by the remote server, and if so,
! 					 * request cancellation of the command; if not, abort
! 					 * gracefully.
  					 */
  					if (PQtransactionStatus(entry->conn) == PQTRANS_ACTIVE)
  					{
--- 677,683 ----
  					 * using an asynchronous execution function, the command
  					 * might not have yet completed.  Check to see if a command
  					 * is still being processed by the remote server, and if so,
! 					 * request cancellation of the command.
  					 */
  					if (PQtransactionStatus(entry->conn) == PQTRANS_ACTIVE)
  					{
***************
*** 694,700 **** pgfdw_xact_callback(XactEvent event, void *arg)
  												errbuf)));
  							PQfreeCancel(cancel);
  						}
- 						break;
  					}
  
  					/* If we're aborting, abort all remote transactions too */
--- 693,698 ----
***************
*** 798,803 **** pgfdw_subxact_callback(SubXactEvent event, SubTransactionId mySubid,
--- 796,825 ----
  		{
  			/* Assume we might have lost track of prepared statements */
  			entry->have_error = true;
+ 
+ 			/*
+ 			 * If a command has been submitted to the remote server by using an
+ 			 * asynchronous execution function, the command might not have yet
+ 			 * completed.  Check to see if a command is still being processed by
+ 			 * the remote server, and if so, request cancellation of the
+ 			 * command.
+ 			 */
+ 			if (PQtransactionStatus(entry->conn) == PQTRANS_ACTIVE)
+ 			{
+ 				PGcancel   *cancel;
+ 				char		errbuf[256];
+ 
+ 				if ((cancel = PQgetCancel(entry->conn)))
+ 				{
+ 					if (!PQcancel(cancel, errbuf, sizeof(errbuf)))
+ 						ereport(WARNING,
+ 								(errcode(ERRCODE_CONNECTION_FAILURE),
+ 								 errmsg("could not send cancel request: %s",
+ 										errbuf)));
+ 					PQfreeCancel(cancel);
+ 				}
+ 			}
+ 
  			/* Rollback all remote subtransactions during abort */
  			snprintf(sql, sizeof(sql),
  					 "ROLLBACK TO SAVEPOINT s%d; RELEASE SAVEPOINT s%d",