conf: call mdb_reader_check() if confdb opening fails

diff --git a/src/libknot/db/db_lmdb.c b/src/libknot/db/db_lmdb.c
index 9341f5dd9e84994b5c019b784e4e3d5fa62503ee..b5eae0944ac1ec41a5eee921470120d52f0ddc9a 100644 (file)
--- a/src/libknot/db/db_lmdb.c
+++ b/src/libknot/db/db_lmdb.c
@@ -1,4 +1,4 @@
-/*  Copyright (C) 2021 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+/*  Copyright (C) 2022 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
 
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
@@ -181,6 +181,13 @@ static int dbase_open(struct lmdb_env *env, struct knot_db_lmdb_opts *opts)
        /* Open the database. */
        MDB_txn *txn = NULL;
        int ret = mdb_txn_begin(env->env, NULL, flags, &txn);
+       if (ret == MDB_READERS_FULL) {
+               int cleared = 0;
+               ret = mdb_reader_check(env->env, &cleared);
+               if (ret == MDB_SUCCESS) {
+                       ret = mdb_txn_begin(env->env, NULL, flags, &txn);
+               }
+       }
        if (ret != MDB_SUCCESS) {
                mdb_env_close(env->env);
                return lmdb_error_to_knot(ret);