aweisberg commented on code in PR #4043: URL: https://github.com/apache/cassandra/pull/4043#discussion_r2027775778
########## src/java/org/apache/cassandra/service/paxos/v1/PrepareCallback.java: ########## @@ -79,8 +86,28 @@ public synchronized void onResponse(Message<PrepareResponse> message) latch.decrement(); } - public Iterable<InetAddressAndPort> replicasMissingMostRecentCommit() + public Iterable<InetAddressAndPort> replicasMissingMostRecentCommit(TableMetadata metadata) { + /** + * this check is only needed for mixed mode operation with 4.0 and can be removed once upgrade support dropped + * see the comment in {@link org.apache.cassandra.distributed.upgrade.MixedModePaxosTTLTest} for a full explanation. + */ + if (DatabaseDescriptor.paxosStatePurging() == Config.PaxosStatePurging.legacy) Review Comment: I wonder how you safely transition to a new Paxos state purging configuration? It's not atomic to change it across the entire cluster. ########## src/java/org/apache/cassandra/service/paxos/v1/PrepareCallback.java: ########## @@ -79,8 +86,28 @@ public synchronized void onResponse(Message<PrepareResponse> message) latch.decrement(); } - public Iterable<InetAddressAndPort> replicasMissingMostRecentCommit() + public Iterable<InetAddressAndPort> replicasMissingMostRecentCommit(TableMetadata metadata) { + /** + * this check is only needed for mixed mode operation with 4.0 and can be removed once upgrade support dropped + * see the comment in {@link org.apache.cassandra.distributed.upgrade.MixedModePaxosTTLTest} for a full explanation. + */ + if (DatabaseDescriptor.paxosStatePurging() == Config.PaxosStatePurging.legacy) + { + // In general, we need every replicas that have answered to the prepare (a quorum) to agree on the MRC (see + // coment in StorageProxy.beginAndRepairPaxos(), but basically we need to make sure at least a quorum of nodes + // have learn a commit before commit a new one otherwise that previous commit is not guaranteed to have reach a + // quorum and further commit may proceed on incomplete information). + // However, if that commit is too hold, it may have been expired from some of the replicas paxos table (we don't Review Comment: s/hold/old, s/replicas/replica's -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: pr-unsubscr...@cassandra.apache.org For additional commands, e-mail: pr-h...@cassandra.apache.org