diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 19a362526d..edbc9ab02a 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -1346,22 +1346,28 @@ PG_FUNCTION_INFO_V1(dblink_cancel_query);
 Datum
 dblink_cancel_query(PG_FUNCTION_ARGS)
 {
-	int			res;
 	PGconn	   *conn;
-	PGcancel   *cancel;
-	char		errbuf[256];
+	PGcancelConn *cancelConn;
+	char	   *msg;
 
 	dblink_init();
 	conn = dblink_get_named_conn(text_to_cstring(PG_GETARG_TEXT_PP(0)));
-	cancel = PQgetCancel(conn);
+	cancelConn = PQcancelCreate(conn);
 
-	res = PQcancel(cancel, errbuf, 256);
-	PQfreeCancel(cancel);
+	PG_TRY();
+	{
+		if (!PQcancelBlocking(cancelConn))
+			msg = pchomp(PQcancelErrorMessage(cancelConn));
+		else
+			msg = "OK";
+	}
+	PG_FINALLY();
+	{
+		PQcancelFinish(cancelConn);
+	}
+	PG_END_TRY();
 
-	if (res == 1)
-		PG_RETURN_TEXT_P(cstring_to_text("OK"));
-	else
-		PG_RETURN_TEXT_P(cstring_to_text(errbuf));
+	PG_RETURN_TEXT_P(cstring_to_text(msg));
 }
 
 
diff --git a/src/fe_utils/connect_utils.c b/src/fe_utils/connect_utils.c
index 808d54461f..5ed9f3ba17 100644
--- a/src/fe_utils/connect_utils.c
+++ b/src/fe_utils/connect_utils.c
@@ -157,19 +157,14 @@ connectMaintenanceDatabase(ConnParams *cparams,
 void
 disconnectDatabase(PGconn *conn)
 {
-	char		errbuf[256];
-
 	Assert(conn != NULL);
 
 	if (PQtransactionStatus(conn) == PQTRANS_ACTIVE)
 	{
-		PGcancel   *cancel;
+		PGcancelConn *cancelConn = PQcancelCreate(conn);
 
-		if ((cancel = PQgetCancel(conn)))
-		{
-			(void) PQcancel(cancel, errbuf, sizeof(errbuf));
-			PQfreeCancel(cancel);
-		}
+		(void) PQcancelBlocking(cancelConn);
+		PQcancelFinish(cancelConn);
 	}
 
 	PQfinish(conn);
diff --git a/src/test/isolation/isolationtester.c b/src/test/isolation/isolationtester.c
index ed110f740f..0b342b5c2b 100644
--- a/src/test/isolation/isolationtester.c
+++ b/src/test/isolation/isolationtester.c
@@ -946,26 +946,21 @@ try_complete_step(TestSpec *testspec, PermutationStep *pstep, int flags)
 			 */
 			if (td > max_step_wait && !canceled)
 			{
-				PGcancel   *cancel = PQgetCancel(conn);
+				PGcancelConn *cancel_conn = PQcancelCreate(conn);
 
-				if (cancel != NULL)
+				if (PQcancelBlocking(cancel_conn))
 				{
-					char		buf[256];
-
-					if (PQcancel(cancel, buf, sizeof(buf)))
-					{
-						/*
-						 * print to stdout not stderr, as this should appear
-						 * in the test case's results
-						 */
-						printf("isolationtester: canceling step %s after %d seconds\n",
-							   step->name, (int) (td / USECS_PER_SEC));
-						canceled = true;
-					}
-					else
-						fprintf(stderr, "PQcancel failed: %s\n", buf);
-					PQfreeCancel(cancel);
+					/*
+					 * print to stdout not stderr, as this should appear in
+					 * the test case's results
+					 */
+					printf("isolationtester: canceling step %s after %d seconds\n",
+						   step->name, (int) (td / USECS_PER_SEC));
+					canceled = true;
 				}
+				else
+					fprintf(stderr, "PQcancel failed: %s\n", PQcancelErrorMessage(cancel_conn));
+				PQcancelFinish(cancel_conn);
 			}
 
 			/*