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https://issues.apache.org/jira/browse/HDFS-16659?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17599240#comment-17599240
]
ASF GitHub Bot commented on HDFS-16659:
---------------------------------------
ZanderXu commented on code in PR #4560:
URL: https://github.com/apache/hadoop/pull/4560#discussion_r961258064
##########
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/qjournal/client/TestQuorumJournalManager.java:
##########
@@ -1122,41 +1115,50 @@ public void testSelectViaRpcTwoJNsError() throws
Exception {
* 4. Observer NameNode try to select EditLogInputStream vis PRC with start
txId 21.
* 5. Journal 1 has some abnormal cases caused slow response.
*
- * And the expected selecting result is: Response should contain 20 Edits
from txId 21 to txId 40.
- * Because there is no Edits from id 21 to 40 in the cache of JournalNode0.
+ * The expected result should contain txn 21 - 40.
*/
@Test
- public void testSelectViaRpcAfterJNJitter() throws Exception {
+ public void testSelectViaRPCAfterJNJitter() throws Exception {
EditLogOutputStream stm = qjm.startLogSegment(
1, NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION);
SettableFuture<Void> slowLog = SettableFuture.create();
Mockito.doReturn(slowLog).when(spies.get(0))
- .sendEdits(eq(1L), eq(11L), eq(1), Mockito.any());
+ .sendEdits(eq(1L), eq(11L), eq(10), Mockito.any());
+ // Successfully write these edits to JN0 ~ JN2
writeTxns(stm, 1, 10);
+ // Failed write these edits to JN0, but successfully write them to JN1 ~
JN2
writeTxns(stm, 11, 10);
- writeTxns(stm, 21, 10);
- writeTxns(stm, 31, 10);
- ListeningExecutorService service = MoreExecutors.listeningDecorator(
- Executors.newSingleThreadExecutor());
- Mockito.doAnswer(invocation -> service.submit(
- () -> {
- ByteArrayOutputStream byteStream = new ByteArrayOutputStream();
- EditLogFileOutputStream.writeHeader(
- NameNodeLayoutVersion.CURRENT_LAYOUT_VERSION,
- new DataOutputStream(byteStream));
- byteStream.write(createTxnData(21, 20));
- Thread.sleep(3000);
- return GetJournaledEditsResponseProto.newBuilder()
- .setTxnCount(20)
- .setEditLog(ByteString.copyFrom(byteStream.toByteArray()))
- .build();
- })
- ).when(spies.get(1)).getJournaledEdits(21,
+ // Successfully write these edits to JN1 ~ JN2
+ writeTxns(stm, 21, 20);
+
+ Semaphore semaphore = new Semaphore(0);
+
+
Mockito.doAnswer((Answer<ListenableFuture<GetJournaledEditsResponseProto>>)
invocation -> {
+ semaphore.release(1);
+ @SuppressWarnings("unchecked")
+ ListenableFuture<GetJournaledEditsResponseProto> result =
+ (ListenableFuture<GetJournaledEditsResponseProto>)
invocation.callRealMethod();
+ return result;
+ }).when(spies.get(0)).getJournaledEdits(21,
+ QuorumJournalManager.QJM_RPC_MAX_TXNS_DEFAULT);
+
+
Mockito.doAnswer((Answer<ListenableFuture<GetJournaledEditsResponseProto>>)
invocation -> {
+ semaphore.release(1);
+ @SuppressWarnings("unchecked")
+ ListenableFuture<GetJournaledEditsResponseProto> result =
+ (ListenableFuture<GetJournaledEditsResponseProto>)
invocation.callRealMethod();
+ return result;
+ }).when(spies.get(1)).getJournaledEdits(21,
QuorumJournalManager.QJM_RPC_MAX_TXNS_DEFAULT);
- GetJournaledEditsResponseProto responseProto = spies.get(2)
- .getJournaledEdits(21, 5000).get();
- assertEquals(20, responseProto.getTxnCount());
+
Mockito.doAnswer((Answer<ListenableFuture<GetJournaledEditsResponseProto>>)
invocation -> {
+ semaphore.acquire(2);
+ @SuppressWarnings("unchecked")
+ ListenableFuture<GetJournaledEditsResponseProto> result =
+ (ListenableFuture<GetJournaledEditsResponseProto>)
invocation.callRealMethod();
+ return result;
+ }).when(spies.get(2)).getJournaledEdits(21,
+ QuorumJournalManager.QJM_RPC_MAX_TXNS_DEFAULT);
Review Comment:
Nice suggestion, thanks.
> JournalNode should throw NewerTxnIdException if SinceTxId is bigger than
> HighestWrittenTxId
> -------------------------------------------------------------------------------------------
>
> Key: HDFS-16659
> URL: https://issues.apache.org/jira/browse/HDFS-16659
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: ZanderXu
> Assignee: ZanderXu
> Priority: Critical
> Labels: pull-request-available
> Time Spent: 1h
> Remaining Estimate: 0h
>
> JournalNode should throw `CacheMissException` if `sinceTxId` is bigger than
> `highestWrittenTxId` during handling `getJournaledEdits` rpc from NNs.
> Current logic may cause in-progress EditlogTailer cannot replay any Edits
> from JournalNodes in some corner cases, resulting in ObserverNameNode cannot
> handle requests from clients.
> Suppose there are 3 journalNodes, JN0 ~ JN1.
> * JN0 has some abnormal cases when Active Namenode is syncing 10 Edits with
> first txid 11
> * NameNode just ignore the abnormal JN0 and continue to sync Edits to Journal
> 1 and 2
> * JN0 backed to health
> * NameNode continue sync 10 Edits with first txid 21.
> * At this point, there are no Edits 11 ~ 30 in the cache of JN0
> * Observer NameNode try to select EditLogInputStream through
> `getJournaledEdits` with since txId 21
> * Journal 2 has some abnormal cases and caused a slow response
> The expected result is: Response should contain 20 Edits from txId 21 to txId
> 30 from JN1 and JN2. Because Active NameNode successfully write these Edits
> to JN1 and JN2 and failed write these edits to JN0.
> But in the current implementation, the response is [Response(0) from JN0,
> Response(10) from JN1], because there are some abnormal cases in JN2, such
> as GC, bad network, cause a slow response. So the `maxAllowedTxns` will be
> 0, NameNode will not replay any Edits.
> As above, the root case is that JournalNode should throw Miss Cache Exception
> when `sinceTxid` is more than `highestWrittenTxId`.
> And the bug code as blew:
> {code:java}
> if (sinceTxId > getHighestWrittenTxId()) {
> // Requested edits that don't exist yet; short-circuit the cache here
> metrics.rpcEmptyResponses.incr();
> return
> GetJournaledEditsResponseProto.newBuilder().setTxnCount(0).build();
> }
> {code}
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