sijie commented on a change in pull request #1549: offloadPrefix implementation
for managed ledger
URL: https://github.com/apache/incubator-pulsar/pull/1549#discussion_r181173676
##########
File path:
managed-ledger/src/main/java/org/apache/bookkeeper/mledger/impl/ManagedLedgerImpl.java
##########
@@ -1850,9 +1854,172 @@ public void offloadFailed(ManagedLedgerException e,
Object ctx) {
@Override
public void asyncOffloadPrefix(Position pos, OffloadCallback callback,
Object ctx) {
- callback.offloadFailed(new ManagedLedgerException("Not implemented"),
ctx);
+ PositionImpl requestOffloadTo = (PositionImpl)pos;
+ if (!isValidPosition(requestOffloadTo)) {
+ callback.offloadFailed(new InvalidCursorPositionException("Invalid
position for offload"), ctx);
+ return;
+ }
+
+ Position firstUnoffloaded;
+
+ List<LedgerInfo> ledgersToOffload = Lists.newArrayList();
+ synchronized (this) {
+ log.info("[{}] Start ledgersOffload. ledgers={} totalSize={}",
name, ledgers.keySet(),
+ TOTAL_SIZE_UPDATER.get(this));
+
+ if (STATE_UPDATER.get(this) == State.Closed) {
+ log.info("[{}] Ignoring offload request since the managed
ledger was already closed", name);
+ callback.offloadFailed(new ManagedLedgerAlreadyClosedException(
+ "Can't offload closed managed
ledger"), ctx);
+ return;
+ }
+
+ long current = ledgers.lastKey();
+
+ // the first ledger which will not be offloaded. Defaults to
current,
+ // in the case that the whole headmap is offloaded. Otherwise it
will
+ // be set as we iterate through the headmap values
+ long firstLedgerRetained = current;
+ for (LedgerInfo ls : ledgers.headMap(current).values()) {
+ if (requestOffloadTo.getLedgerId() > ls.getLedgerId()) {
+ if (!ls.hasOffloadContext()) {
+ ledgersToOffload.add(ls);
+ }
+ } else {
+ firstLedgerRetained = ls.getLedgerId();
+ break;
+ }
+ }
+ firstUnoffloaded = PositionImpl.get(firstLedgerRetained, 0);
+ }
+
+ if (ledgersToOffload.isEmpty()) {
+ callback.offloadComplete(firstUnoffloaded, ctx);
+ return;
+ }
+
+ log.info("[{}] Going to offload ledgers {}", name,
+ ledgersToOffload.stream().map(l ->
l.getLedgerId()).collect(Collectors.toList()));
+ List< Pair<Long, CompletableFuture<byte[]>> > contexts =
ledgersToOffload.stream()
+ .map(info -> {
+ long ledgerId = info.getLedgerId();
+ Map<String, String> extraMetadata =
ImmutableMap.of("ManagedLedgerName", name);
+ CompletableFuture<byte[]> context =
getLedgerHandle(ledgerId).thenCompose(
+ readHandle ->
config.getLedgerOffloader().offload(readHandle, extraMetadata));
+ return Pair.of(ledgerId, context);
+ }).collect(Collectors.toList());
+
+ CompletableFuture.allOf(contexts.stream().map(p ->
p.getRight()).toArray(CompletableFuture[]::new))
+ .whenComplete((ignore, offloadException) -> {
+ // If any of the offload operations failed
offloadException will
+ // be set. However some of the operations could have been
successful.
+ // If so, save the contexts for the successful prefix and
notify the client
+ // of the error if any occurred.
+ List<Pair<Long, byte[]>> successfulOffloads =
Lists.newArrayList();
+ int errors = 0;
+ synchronized (this) {
+ ledgersListMutex.lock();
+
+ // loop through results of offload operations. If an
error occurred
+ // check that the ledger still exists for the ML. If
not, then it was
+ // trimmed and the error can be ignored.
+ for (Pair<Long, CompletableFuture<byte[]>> context :
contexts) {
+ if (context.getRight().isCompletedExceptionally())
{
+ if (ledgers.containsKey(context.getLeft())) {
+ errors++;
+ }
+ } else {
+
successfulOffloads.add(Pair.of(context.getLeft(), context.getRight().join()));
+ }
+ }
+ ledgersListMutex.unlock();
+ }
+ log.info("[{}] All offload operations complete, {}
successful, {} errors",
+ name, successfulOffloads.size(), errors);
+
+ int errorsToReport = errors; // effectively final so can
be used in lambda
+ if (successfulOffloads.size() > 0) {
+
updateLedgerInfoForOffloaded(successfulOffloads).whenComplete(
+ (ignore2, exception) -> {
+ if (exception != null) {
+ callback.offloadFailed(new
ManagedLedgerException(exception), ctx);
+ } else if (offloadException != null &&
errorsToReport > 0) {
+ callback.offloadFailed(new
ManagedLedgerException(offloadException), ctx);
+ } else {
+
callback.offloadComplete(firstUnoffloaded, ctx);
+ }
+ });
+ } else {
+ // All failed, so throw up the error
+ callback.offloadFailed(new
ManagedLedgerException(offloadException), ctx);
+ }
+ });
}
+ private CompletableFuture<Void>
updateLedgerInfoForOffloaded(List<Pair<Long, byte[]>> contexts) {
+ CompletableFuture<Void> promise = new CompletableFuture<>();
+ synchronized (this) {
+ ledgersListMutex.lock();
+
+ contexts.forEach((context) -> {
+ long ledgerId = context.getLeft();
+ LedgerInfo oldInfo = ledgers.get(ledgerId);
+ if (oldInfo == null) {
+ cleanupOffloadedOnFailure(context.getLeft(),
context.getRight(),
Review comment:
if pulsar broker fails during offloading, who is responsible for cleaning up
those "partially completed" ledgers in tier storage?
I was imaging a sequence like below:
- update metadata indicate a ledger is offloading
- offloading
- update metadata indicate a ledger is offloaded
so if a ML is crashed during offloading, when it is recovered and start
offloading again, it will know the state from ledger info. however I don't see
metadata being updated before offloading, do I miss anything here?
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