diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c
index a90bdb8ab6d..56a8266bc3f 100644
--- a/src/interfaces/libpq/fe-connect.c
+++ b/src/interfaces/libpq/fe-connect.c
@@ -3952,6 +3952,7 @@ makeEmptyPGconn(void)
 	conn->verbosity = PQERRORS_DEFAULT;
 	conn->show_context = PQSHOW_CONTEXT_ERRORS;
 	conn->sock = PGINVALID_SOCKET;
+	conn->Pfdebug = NULL;
 
 	/*
 	 * We try to send at least 8K at a time, which is the usual size of pipe