ifesdjeen commented on code in PR #3288:
URL: https://github.com/apache/cassandra/pull/3288#discussion_r1598049800
##########
src/java/org/apache/cassandra/tcm/PeerLogFetcher.java:
##########
@@ -74,40 +74,54 @@ public ClusterMetadata
fetchLogEntriesAndWait(InetAddressAndPort remote, Epoch a
public Future<ClusterMetadata> asyncFetchLog(InetAddressAndPort remote,
Epoch awaitAtleast)
{
- Function<Promise<LogState>, ClusterMetadata> fn = promise ->
fetchLogEntriesAndWaitInternal(promise, remote, awaitAtleast);
- return EpochAwareDebounce.instance.getAsync(fn, awaitAtleast);
+ return EpochAwareDebounce.instance.getAsync(() ->
fetchLogEntriesAndWaitInternal(remote, awaitAtleast), awaitAtleast);
}
- private ClusterMetadata fetchLogEntriesAndWaitInternal(Promise<LogState>
remoteRequest, InetAddressAndPort remote, Epoch awaitAtleast)
+ private Future<ClusterMetadata>
fetchLogEntriesAndWaitInternal(InetAddressAndPort remote, Epoch awaitAtleast)
{
Epoch before = ClusterMetadata.current().epoch;
if (before.isEqualOrAfter(awaitAtleast))
- return ClusterMetadata.current();
+ {
+ Promise<ClusterMetadata> res = new AsyncPromise<>();
+ res.setSuccess(ClusterMetadata.current());
+ return res;
+ }
+ Promise<LogState> fetchRes = new AsyncPromise<>();
logger.info("Fetching log from {}, at least {}", remote, awaitAtleast);
-
try (Timer.Context ctx =
TCMMetrics.instance.fetchPeerLogLatency.time())
{
- RemoteProcessor.sendWithCallbackAsync(remoteRequest,
+ RemoteProcessor.sendWithCallbackAsync(fetchRes,
Verb.TCM_FETCH_PEER_LOG_REQ,
new FetchPeerLog(before),
new
RemoteProcessor.CandidateIterator(Collections.singletonList(remote)),
Retry.Deadline.after(DatabaseDescriptor.getCmsAwaitTimeout().to(TimeUnit.NANOSECONDS),
new
Retry.Jitter(TCMMetrics.instance.fetchLogRetries)));
- LogState logState = remoteRequest.awaitUninterruptibly().get();
- log.append(logState);
- ClusterMetadata fetched = log.waitForHighestConsecutive();
- if (fetched.epoch.isEqualOrAfter(awaitAtleast))
- {
- TCMMetrics.instance.peerLogEntriesFetched(before,
logState.latestEpoch());
- return fetched;
- }
+
+ return fetchRes.map((logState) -> {
+ log.append(logState);
+ ClusterMetadata fetched = log.waitForHighestConsecutive();
+ if (fetched.epoch.isEqualOrAfter(awaitAtleast))
+ {
+ TCMMetrics.instance.peerLogEntriesFetched(before,
logState.latestEpoch());
+ return fetched;
+ }
+ else
+ {
+ throw new IllegalStateException(String.format("Queried for
epoch %s, but could not catch up", awaitAtleast));
Review Comment:
Right now, we will log this (rare) exception, which ji think is a reasonable
behaviour.
On the other hand, if we have a listener, it will have to deal with
exception one way or the other: this seems ok, too.
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