aweisberg commented on code in PR #3842:
URL: https://github.com/apache/cassandra/pull/3842#discussion_r1932793214
##########
src/java/org/apache/cassandra/service/accord/AccordConfigurationService.java:
##########
@@ -407,7 +407,11 @@ void maybeReportMetadata(ClusterMetadata metadata)
long epoch = metadata.epoch.getEpoch();
synchronized (epochs)
{
- if (epochs.maxEpoch() == 0)
+ long maxEpoch = epochs.maxEpoch();
+ if (maxEpoch >= epoch)
Review Comment:
Does Accord knowing about the epoch guarantee that TCM has already loaded
it? We don't want to skip the TCM loading step by not indirectly calling
`fetchTopologyInternal` or something to ensure TCM loaded it.
##########
src/java/org/apache/cassandra/service/accord/AccordService.java:
##########
@@ -410,48 +413,67 @@ public synchronized void startup()
}
/**
- * Queries peers to discover min epoch
+ * Queries peers to discover min epoch, and then fetches all topologies
between min and current epochs
*/
- private long fetchMinEpoch()
+ private List<Topology> fetchTopologies(long minEpoch, ClusterMetadata
metadata) throws ExecutionException, InterruptedException
{
- ClusterMetadata metadata = ClusterMetadata.current();
- Map<InetAddressAndPort, Set<TokenRange>> peers = new HashMap<>();
- for (KeyspaceMetadata keyspace : metadata.schema.getKeyspaces())
+ if (configService.maxEpoch() >= metadata.epoch.getEpoch())
{
- List<TableMetadata> tables =
keyspace.tables.stream().filter(TableMetadata::requiresAccordSupport).collect(Collectors.toList());
- if (tables.isEmpty())
- continue;
- DataPlacement current =
metadata.placements.get(keyspace.params.replication);
- DataPlacement settled =
metadata.writePlacementAllSettled(keyspace);
- Sets.SetView<InetAddressAndPort> alive =
Sets.intersection(settled.writes.byEndpoint().keySet(),
current.writes.byEndpoint().keySet());
- InetAddressAndPort self = FBUtilities.getBroadcastAddressAndPort();
- settled.writes.forEach((range, group) -> {
- if (group.endpoints().contains(self))
- {
- for (InetAddressAndPort peer : group.endpoints())
- {
- if (peer.equals(self) || !alive.contains(peer))
continue;
- for (TableMetadata table : tables)
- peers.computeIfAbsent(peer, i -> new
HashSet<>()).add(AccordTopology.fullRange(table.id));
- }
- }
- });
+ logger.info("Accord epoch {} matches TCM. All topologies are known
locally", metadata.epoch);
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));
}
+
+ Set<InetAddressAndPort> peers = new HashSet<>();
+ peers.addAll(metadata.directory.allAddresses());
+ peers.remove(FBUtilities.getBroadcastAddressAndPort());
+
+ // No peers: single node cluster or first node to boot
if (peers.isEmpty())
- return -1;
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));;
+
+ // Bootstrap, fetch min epoch
+ if (minEpoch == 0)
+ {
+ long fetched = findMinEpoch(SharedContext.Global.instance, peers);
+ // No other node has advanced epoch just yet
+ if (fetched == 0)
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));
+
+ minEpoch = fetched;
+ }
+
+ long maxEpoch = metadata.epoch.getEpoch();
+
+ // If we are behind minEpoch, catch up to at least minEpoch
+ if (metadata.epoch.getEpoch() < minEpoch)
+ {
+ minEpoch = metadata.epoch.getEpoch();
+ maxEpoch = minEpoch;
+ }
+
+ List<Future<Topology>> futures = new ArrayList<>();
+ logger.info("Discovered min epoch of {}. Proceeding to fetch epochs up
to {}.", minEpoch, maxEpoch);
+
+ for (long epoch = minEpoch; epoch <= maxEpoch; epoch++)
+ futures.add(FetchTopology.fetch(SharedContext.Global.instance,
peers, epoch));
+
+ FBUtilities.waitOnFutures(futures);
+ List<Topology> topologies = new ArrayList<>(futures.size());
+ for (Future<Topology> future : futures)
+ topologies.add(future.get());
- Long minEpoch = findMinEpoch(SharedContext.Global.instance, peers);
- if (minEpoch == null)
- return -1;
- return minEpoch;
+ return topologies;
}
@VisibleForTesting
- static Long findMinEpoch(SharedContext context, Map<InetAddressAndPort,
Set<TokenRange>> peers)
+ static long findMinEpoch(SharedContext context, Set<InetAddressAndPort>
peers)
{
try
{
- return FetchMinEpoch.fetch(context, peers).get();
+ Long result = FetchMinEpoch.fetch(context, peers).get();
+ if (result == null)
+ return 0L;
+ return result.longValue();
Review Comment:
Won't this unbox automatically?
##########
src/java/org/apache/cassandra/service/accord/FetchTopology.java:
##########
@@ -123,18 +116,20 @@ public Response(long epoch, Topology topology)
long epoch = message.payload.epoch;
Topology topology =
AccordService.instance().topology().maybeGlobalForEpoch(epoch);
if (topology == null)
- MessagingService.instance().respond(Response.UNKNOWN, message);
+ MessagingService.instance().respond(Response.unkonwn(epoch),
message);
else
MessagingService.instance().respond(new Response(epoch, topology),
message);
};
+ private static final Logger logger =
LoggerFactory.getLogger(FetchTopology.class);
Review Comment:
`logger` goes at the top? Also unused.
##########
src/java/org/apache/cassandra/service/accord/FetchMinEpoch.java:
##########
@@ -145,21 +108,22 @@ public static Future<Long> fetch(SharedContext context,
Map<InetAddressAndPort,
}
@VisibleForTesting
- static Future<Long> fetch(SharedContext context, InetAddressAndPort to,
Set<TokenRange> value)
+ static Future<Long> fetch(SharedContext context, InetAddressAndPort to)
{
- FetchMinEpoch req = new FetchMinEpoch(value);
- return context.messaging().<FetchMinEpoch,
FetchMinEpoch.Response>sendWithRetries(Backoff.NO_OP.INSTANCE,
-
MessageDelivery.ImmediateRetryScheduler.instance,
-
Verb.ACCORD_FETCH_MIN_EPOCH_REQ, req,
+ Backoff backoff = Backoff.fromConfig(context,
DatabaseDescriptor.getAccord().minEpochSyncRetry);
+ return context.messaging().<FetchMinEpoch,
FetchMinEpoch.Response>sendWithRetries(backoff,
+
context.optionalTasks()::schedule,
+
Verb.ACCORD_FETCH_MIN_EPOCH_REQ,
+
FetchMinEpoch.instance,
Iterators.cycle(to),
-
RetryPredicate.times(DatabaseDescriptor.getAccord().minEpochSyncRetry.maxAttempts.value),
+
RetryPredicate.ALWAYS_RETRY,
Review Comment:
Does this mean that fetching the min epoch requires all nodes to be up to
complete? Just looking at how this is accumulated by the caller of `fetch`
which combines all the futures and can't complete until every future completes
which means any down node would stop this from working?
##########
src/java/org/apache/cassandra/service/accord/AccordService.java:
##########
@@ -377,24 +371,33 @@ public synchronized void startup()
node.commandStores().restoreShardStateUnsafe(topology ->
configService.reportTopology(topology, true, true));
configService.start();
- long minEpoch = fetchMinEpoch();
- if (minEpoch >= 0)
+ try
{
- for (long epoch = minEpoch; epoch <= metadata.epoch.getEpoch();
epoch++)
- node.configService().fetchTopologyForEpoch(epoch);
+ // Fetch topologies up to current
+ List<Topology> topologies = fetchTopologies(0, metadata);
Review Comment:
Maybe make 0 a constant indicating that it is actually supposed to find the
`minEpoch` to fetch?
##########
src/java/org/apache/cassandra/service/accord/AccordConfigurationService.java:
##########
@@ -420,14 +424,17 @@ void maybeReportMetadata(ClusterMetadata metadata)
@Override
protected void fetchTopologyInternal(long epoch)
{
+ if (ClusterMetadata.current().epoch.getEpoch() < epoch)
+
ClusterMetadataService.instance().fetchLogFromCMS(Epoch.create(epoch));
+
try
{
Set<InetAddressAndPort> peers = new
HashSet<>(ClusterMetadata.current().directory.allJoinedEndpoints());
peers.remove(FBUtilities.getBroadcastAddressAndPort());
if (peers.isEmpty())
return;
Topology topology;
- while ((topology
=FetchTopology.fetch(SharedContext.Global.instance, peers, epoch).get()) ==
null) {}
+ while ((topology =
FetchTopology.fetch(SharedContext.Global.instance, peers, epoch).get()) ==
null) {}
Review Comment:
Why do we need to run `FetchTopology` here if we would indirectly get the
topology from `
ClusterMetadataService.instance().fetchLogFromCMS(Epoch.create(epoch));`
##########
src/java/org/apache/cassandra/service/accord/AccordService.java:
##########
@@ -410,48 +413,67 @@ public synchronized void startup()
}
/**
- * Queries peers to discover min epoch
+ * Queries peers to discover min epoch, and then fetches all topologies
between min and current epochs
*/
- private long fetchMinEpoch()
+ private List<Topology> fetchTopologies(long minEpoch, ClusterMetadata
metadata) throws ExecutionException, InterruptedException
{
- ClusterMetadata metadata = ClusterMetadata.current();
- Map<InetAddressAndPort, Set<TokenRange>> peers = new HashMap<>();
- for (KeyspaceMetadata keyspace : metadata.schema.getKeyspaces())
+ if (configService.maxEpoch() >= metadata.epoch.getEpoch())
{
- List<TableMetadata> tables =
keyspace.tables.stream().filter(TableMetadata::requiresAccordSupport).collect(Collectors.toList());
- if (tables.isEmpty())
- continue;
- DataPlacement current =
metadata.placements.get(keyspace.params.replication);
- DataPlacement settled =
metadata.writePlacementAllSettled(keyspace);
- Sets.SetView<InetAddressAndPort> alive =
Sets.intersection(settled.writes.byEndpoint().keySet(),
current.writes.byEndpoint().keySet());
- InetAddressAndPort self = FBUtilities.getBroadcastAddressAndPort();
- settled.writes.forEach((range, group) -> {
- if (group.endpoints().contains(self))
- {
- for (InetAddressAndPort peer : group.endpoints())
- {
- if (peer.equals(self) || !alive.contains(peer))
continue;
- for (TableMetadata table : tables)
- peers.computeIfAbsent(peer, i -> new
HashSet<>()).add(AccordTopology.fullRange(table.id));
- }
- }
- });
+ logger.info("Accord epoch {} matches TCM. All topologies are known
locally", metadata.epoch);
Review Comment:
I don't know why this is true so I am just going to have to take it on faith.
##########
src/java/org/apache/cassandra/service/accord/AccordConfigurationService.java:
##########
@@ -420,14 +424,17 @@ void maybeReportMetadata(ClusterMetadata metadata)
@Override
protected void fetchTopologyInternal(long epoch)
{
+ if (ClusterMetadata.current().epoch.getEpoch() < epoch)
Review Comment:
Had to put this on the migration stage on my branch
##########
test/distributed/org/apache/cassandra/distributed/test/accord/AccordDropKeyspaceTest.java:
##########
@@ -35,8 +34,7 @@ public void dropKeyspace() throws IOException
int steps = 5;
try (Cluster cluster = Cluster.build(3)
.withoutVNodes()
- .withConfig(c -> c.with(Feature.values())
Review Comment:
When I merged I set it explicitly to `GOSSIP, NETWORK, NATIVE_PROTOCOL` but
we should probably go back to `values` if the tests can run fine now that we
know that `BLANK_GOSSIP` is ignored.
##########
src/java/org/apache/cassandra/service/accord/FetchTopology.java:
##########
@@ -123,18 +116,20 @@ public Response(long epoch, Topology topology)
long epoch = message.payload.epoch;
Topology topology =
AccordService.instance().topology().maybeGlobalForEpoch(epoch);
if (topology == null)
- MessagingService.instance().respond(Response.UNKNOWN, message);
+ MessagingService.instance().respond(Response.unkonwn(epoch),
message);
Review Comment:
Is this for test code that can catch the actual exception?
##########
src/java/org/apache/cassandra/service/accord/AccordService.java:
##########
@@ -410,48 +413,67 @@ public synchronized void startup()
}
/**
- * Queries peers to discover min epoch
+ * Queries peers to discover min epoch, and then fetches all topologies
between min and current epochs
*/
- private long fetchMinEpoch()
+ private List<Topology> fetchTopologies(long minEpoch, ClusterMetadata
metadata) throws ExecutionException, InterruptedException
{
- ClusterMetadata metadata = ClusterMetadata.current();
- Map<InetAddressAndPort, Set<TokenRange>> peers = new HashMap<>();
- for (KeyspaceMetadata keyspace : metadata.schema.getKeyspaces())
+ if (configService.maxEpoch() >= metadata.epoch.getEpoch())
{
- List<TableMetadata> tables =
keyspace.tables.stream().filter(TableMetadata::requiresAccordSupport).collect(Collectors.toList());
- if (tables.isEmpty())
- continue;
- DataPlacement current =
metadata.placements.get(keyspace.params.replication);
- DataPlacement settled =
metadata.writePlacementAllSettled(keyspace);
- Sets.SetView<InetAddressAndPort> alive =
Sets.intersection(settled.writes.byEndpoint().keySet(),
current.writes.byEndpoint().keySet());
- InetAddressAndPort self = FBUtilities.getBroadcastAddressAndPort();
- settled.writes.forEach((range, group) -> {
- if (group.endpoints().contains(self))
- {
- for (InetAddressAndPort peer : group.endpoints())
- {
- if (peer.equals(self) || !alive.contains(peer))
continue;
- for (TableMetadata table : tables)
- peers.computeIfAbsent(peer, i -> new
HashSet<>()).add(AccordTopology.fullRange(table.id));
- }
- }
- });
+ logger.info("Accord epoch {} matches TCM. All topologies are known
locally", metadata.epoch);
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));
}
+
+ Set<InetAddressAndPort> peers = new HashSet<>();
+ peers.addAll(metadata.directory.allAddresses());
+ peers.remove(FBUtilities.getBroadcastAddressAndPort());
+
+ // No peers: single node cluster or first node to boot
if (peers.isEmpty())
- return -1;
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));;
+
+ // Bootstrap, fetch min epoch
+ if (minEpoch == 0)
Review Comment:
OK, that makes 0 sneaky. I guess 0 is the empty epoch so we never need to
fetch it? It might be better/clearer to use a boxed Long and null or a constant.
##########
test/unit/org/apache/cassandra/service/accord/FetchMinEpochTest.java:
##########
@@ -271,21 +223,21 @@ private static MessageDelivery.FailedResponseException
getFailedResponseExceptio
}
catch (ExecutionException e)
{
- if (e.getCause() instanceof
MessageDelivery.FailedResponseException)
+ if (e.getCause() instanceof MessageDelivery.MaxRetriesException)
{
- exception = (MessageDelivery.FailedResponseException)
e.getCause();
+ maxRetries = (MessageDelivery.MaxRetriesException)
e.getCause();
}
else
{
throw e;
}
}
- return exception;
+ return maxRetries;
}
- private static MessageDelivery.MaxRetriesException
getMaxRetriesException(Future<Long> f) throws InterruptedException,
ExecutionException
+ private static MessageDelivery.FailedResponseException
getFailedResponseException(Future<Long> f) throws InterruptedException,
ExecutionException
Review Comment:
This method is unused
##########
src/java/org/apache/cassandra/service/accord/AccordService.java:
##########
@@ -410,48 +413,67 @@ public synchronized void startup()
}
/**
- * Queries peers to discover min epoch
+ * Queries peers to discover min epoch, and then fetches all topologies
between min and current epochs
*/
- private long fetchMinEpoch()
+ private List<Topology> fetchTopologies(long minEpoch, ClusterMetadata
metadata) throws ExecutionException, InterruptedException
{
- ClusterMetadata metadata = ClusterMetadata.current();
- Map<InetAddressAndPort, Set<TokenRange>> peers = new HashMap<>();
- for (KeyspaceMetadata keyspace : metadata.schema.getKeyspaces())
+ if (configService.maxEpoch() >= metadata.epoch.getEpoch())
{
- List<TableMetadata> tables =
keyspace.tables.stream().filter(TableMetadata::requiresAccordSupport).collect(Collectors.toList());
- if (tables.isEmpty())
- continue;
- DataPlacement current =
metadata.placements.get(keyspace.params.replication);
- DataPlacement settled =
metadata.writePlacementAllSettled(keyspace);
- Sets.SetView<InetAddressAndPort> alive =
Sets.intersection(settled.writes.byEndpoint().keySet(),
current.writes.byEndpoint().keySet());
- InetAddressAndPort self = FBUtilities.getBroadcastAddressAndPort();
- settled.writes.forEach((range, group) -> {
- if (group.endpoints().contains(self))
- {
- for (InetAddressAndPort peer : group.endpoints())
- {
- if (peer.equals(self) || !alive.contains(peer))
continue;
- for (TableMetadata table : tables)
- peers.computeIfAbsent(peer, i -> new
HashSet<>()).add(AccordTopology.fullRange(table.id));
- }
- }
- });
+ logger.info("Accord epoch {} matches TCM. All topologies are known
locally", metadata.epoch);
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));
}
+
+ Set<InetAddressAndPort> peers = new HashSet<>();
+ peers.addAll(metadata.directory.allAddresses());
+ peers.remove(FBUtilities.getBroadcastAddressAndPort());
+
+ // No peers: single node cluster or first node to boot
if (peers.isEmpty())
- return -1;
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));;
+
+ // Bootstrap, fetch min epoch
+ if (minEpoch == 0)
+ {
+ long fetched = findMinEpoch(SharedContext.Global.instance, peers);
+ // No other node has advanced epoch just yet
+ if (fetched == 0)
+ return
Collections.singletonList(AccordTopology.createAccordTopology(metadata));
+
+ minEpoch = fetched;
+ }
+
+ long maxEpoch = metadata.epoch.getEpoch();
+
+ // If we are behind minEpoch, catch up to at least minEpoch
+ if (metadata.epoch.getEpoch() < minEpoch)
+ {
+ minEpoch = metadata.epoch.getEpoch();
+ maxEpoch = minEpoch;
+ }
+
+ List<Future<Topology>> futures = new ArrayList<>();
+ logger.info("Discovered min epoch of {}. Proceeding to fetch epochs up
to {}.", minEpoch, maxEpoch);
+
+ for (long epoch = minEpoch; epoch <= maxEpoch; epoch++)
+ futures.add(FetchTopology.fetch(SharedContext.Global.instance,
peers, epoch));
Review Comment:
This is going to be kind of a flood if you have to collect a lot of these.
Maybe not an issue if it's just one node.
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