From: Peter van Dijk <peter.van.dijk@powerdns.com>
Date: Thu, 6 Jul 2023 13:09:07 +0000 (+0200)
Subject: auth lmdb: in Lightning Stream mode, during deleteDomain, use RW transaction to get... 
X-Git-Tag: rec-5.0.0-alpha1~127^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=refs%2Fpull%2F12990%2Fhead;p=thirdparty%2Fpdns.git

auth lmdb: in Lightning Stream mode, during deleteDomain, use RW transaction to get ID list
---

diff --git a/modules/lmdbbackend/lmdbbackend.cc b/modules/lmdbbackend/lmdbbackend.cc
index ada437db98..7a062b24d5 100644
--- a/modules/lmdbbackend/lmdbbackend.cc
+++ b/modules/lmdbbackend/lmdbbackend.cc
@@ -1321,7 +1321,11 @@ bool LMDBBackend::deleteDomain(const DNSName& domain)
     idvec.push_back(txn.get<0>(domain, di));
   }
   else {
-    auto txn = d_tdomains->getROTransaction();
+    // this transaction used to be RO.
+    // it is now RW to narrow a race window between PowerDNS and Lightning Stream
+    // FIXME: turn the entire delete, including this ID scan, into one RW transaction
+    // when doing that, first do a short RO check to see if we actually have anything to delete
+    auto txn = d_tdomains->getRWTransaction();
 
     txn.get_multi<0>(domain, idvec);
   }