--- a/src/backend/libpq/pqmq.c
+++ b/src/backend/libpq/pqmq.c
@@ -26,7 +26,7 @@
static shm_mq_handle *pq_mq_handle;
static bool pq_mq_busy = false;
static pid_t pq_mq_parallel_leader_pid = 0;
-static pid_t pq_mq_parallel_leader_backend_id = InvalidBackendId;
+static pid_t pq_mq_parallel_leader_proc_number = INVALID_PROC_NUMBER;
I guess it was a historical mistake that this variable of type pid_t
instead of BackendId, but now it should be ProcNumber?