diff --git a/contrib/dlz/modules/include/dlz_list.h b/contrib/dlz/modules/include/dlz_list.h
index 202bc0690a..077ae89a73 100644
--- a/contrib/dlz/modules/include/dlz_list.h
+++ b/contrib/dlz/modules/include/dlz_list.h
@@ -54,3 +54,17 @@
 
 #define DLZ_LIST_PREV(elt, link) ((elt)->link.prev)
 #define DLZ_LIST_NEXT(elt, link) ((elt)->link.next)
+
+#define DLZ_LIST_UNLINK(list, elt, link)                                \
+	do {                                                            \
+		if ((elt)->link.next != NULL)                           \
+			(elt)->link.next->link.prev = (elt)->link.prev; \
+		else                                                    \
+			(list).tail = (elt)->link.prev;                 \
+		if ((elt)->link.prev != NULL)                           \
+			(elt)->link.prev->link.next = (elt)->link.next; \
+		else                                                    \
+			(list).head = (elt)->link.next;                 \
+		(elt)->link.prev = (void *)(-1);                        \
+		(elt)->link.next = (void *)(-1);                        \
+	} while (0)
diff --git a/contrib/dlz/modules/mysqldyn/dlz_mysqldyn_mod.c b/contrib/dlz/modules/mysqldyn/dlz_mysqldyn_mod.c
index 9af5a7e692..bdd0bccdc6 100644
--- a/contrib/dlz/modules/mysqldyn/dlz_mysqldyn_mod.c
+++ b/contrib/dlz/modules/mysqldyn/dlz_mysqldyn_mod.c
@@ -461,9 +461,8 @@ build_query(mysql_data_t *state, mysql_instance_t *dbi, const char *command,
 fail:
 	va_end(ap1);
 
-	for (item = DLZ_LIST_HEAD(arglist); item != NULL;
-	     item = DLZ_LIST_NEXT(item, link))
-	{
+	while ((item = DLZ_LIST_HEAD(arglist)) != NULL) {
+		DLZ_LIST_UNLINK(arglist, item, link);
 		if (item->arg != NULL) {
 			free(item->arg);
 		}
@@ -1078,6 +1077,8 @@ dlz_destroy(void *dbdata) {
 isc_result_t
 dlz_findzonedb(void *dbdata, const char *name, dns_clientinfomethods_t *methods,
 	       dns_clientinfo_t *clientinfo) {
+	UNUSED(methods);
+	UNUSED(clientinfo);
 	isc_result_t result = ISC_R_SUCCESS;
 	mysql_data_t *state = (mysql_data_t *)dbdata;
 	MYSQL_RES *res;
@@ -1110,6 +1111,8 @@ isc_result_t
 dlz_lookup(const char *zone, const char *name, void *dbdata,
 	   dns_sdlzlookup_t *lookup, dns_clientinfomethods_t *methods,
 	   dns_clientinfo_t *clientinfo) {
+	UNUSED(methods);
+	UNUSED(clientinfo);
 	isc_result_t result;
 	mysql_data_t *state = (mysql_data_t *)dbdata;
 	bool found = false;