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https://issues.apache.org/jira/browse/SENTRY-1771?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16021834#comment-16021834
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Na Li commented on SENTRY-1771:
-------------------------------

I have added more logging in DBUpdateForwarder and delay in generating full 
permission update to reproduce this issue of requesting concurrent full 
permission updates in TestHDFSIntegrationEnd2End and real cluster, but I could 
not reproduce this issue.

What I observed behavior is:
1. The requests are sequential. I always see the HDFS request returns before 
next request is received at Sentry.
2. Full snapshot is obtained only once for permission and once for path. After 
that Sentry only responds with delta updates if there are updates. Otherwise, 
Sentry sends empty updates.

By looking at the code, the only possible situations that full updates are 
generated more than once is
1. The SentryStore cleans up the path change table and perm change table. The 
default interval is 12 hours (SENTRY_STORE_CLEAN_PERIOD_SECONDS_DEFAULT). When 
some changes are purged but not received by HDFS, full update is be generated.
2. There is no entries in perm change table. Then full update for permission 
will be generated for each request because changeID is 0.  ChangeID could be 0, 
if Sentry server has been running before enabling SentryPlugin(HDFS Sync 
feature). 

I suggest to add more log message at debug level and monitor this issue. 


> HDFS client requests full permission update multiple times
> ----------------------------------------------------------
>
>                 Key: SENTRY-1771
>                 URL: https://issues.apache.org/jira/browse/SENTRY-1771
>             Project: Sentry
>          Issue Type: Sub-task
>          Components: Sentry
>    Affects Versions: sentry-ha-redesign
>            Reporter: Na Li
>            Assignee: Na Li
>              Labels: hfs
>             Fix For: sentry-ha-redesign
>
>         Attachments: SENTRY-1771.001-sentry-ha-redesign.patch
>
>
> When running performance test, we found there are OOM, and the memory dump 
> shows that there are 6 requests from HDFS to get full update for permission 
> when OOM happens. 
> Server sends back full update if the sequence number from client is 1 at 
> DBUpdateForwarder.getAllUpdatesFrom()
> Example of call stack at the Sentry server is 
>   166,999K (17.4%) (org.datanucleus.ExecutionContextThreadedImpl)
>      <-- Java Local (org.datanucleus.ExecutionContextThreadedImpl) 
> [@c01196f0,@c07dbb10]
>   99,019K (10.3%) (j.u.HashSet, j.u.HashMap)
>      <-- 
> org.datanucleus.ExecutionContextThreadedImpl.reachabilityPersistedIds <-- 
> Java Local (org.datanucleus.ExecutionContextThreadedImpl) 
> [@c01196f0,@c07dbb10]
>   85,196K (8.9%) (org.datanucleus.identity.OIDImpl)
>      <--  {j.u.HashSet} <-- 
> org.datanucleus.ExecutionContextThreadedImpl.reachabilityPersistedIds <-- 
> Java Local (org.datanucleus.ExecutionContextThreadedImpl) 
> [@c01196f0,@c07dbb10]
>   64,606K (6.7%)
>      <-- org.datanucleus.identity.OIDImpl.toString <--  {j.u.HashSet} <-- 
> org.datanucleus.ExecutionContextThreadedImpl.reachabilityPersistedIds <-- 
> Java Local (org.datanucleus.ExecutionContextThreadedImpl) 
> [@c01196f0,@c07dbb10]
>   GC root stack trace:
>     
> org.datanucleus.store.rdbms.scostore.JoinSetStore.iterator(JoinSetStore.java:914)
>     org.datanucleus.store.types.backed.Set.loadFromStore(Set.java:323)
>     org.datanucleus.store.types.backed.Set.initialise(Set.java:272)
>     org.datanucleus.store.types.SCOUtils.createSCOWrapper(SCOUtils.java:256)
>     org.datanucleus.store.types.SCOUtils.newSCOInstance(SCOUtils.java:142)
>     
> org.datanucleus.store.rdbms.mapping.java.AbstractContainerMapping.replaceFieldWithWrapper(AbstractContainerMapping.java:399)
>     
> org.datanucleus.store.rdbms.mapping.java.AbstractContainerMapping.postFetch(AbstractContainerMapping.java:417)
>     
> org.datanucleus.store.rdbms.request.FetchRequest.execute(FetchRequest.java:420)
>     
> org.datanucleus.store.rdbms.RDBMSPersistenceHandler.fetchObject(RDBMSPersistenceHandler.java:324)
>     
> org.datanucleus.state.AbstractStateManager.loadFieldsFromDatastore(AbstractStateManager.java:1122)
>     
> org.datanucleus.state.JDOStateManager.loadUnloadedFieldsInFetchPlan(JDOStateManager.java:3000)
>     
> org.datanucleus.state.AbstractStateManager.loadFieldsInFetchPlan(AbstractStateManager.java:1064)
>     
> org.datanucleus.ExecutionContextImpl.performDetachAllOnTxnEndPreparation(ExecutionContextImpl.java:4574)
>     
> org.datanucleus.ExecutionContextImpl.preCommit(ExecutionContextImpl.java:4259)
>     
> org.datanucleus.ExecutionContextImpl.transactionPreCommit(ExecutionContextImpl.java:654)
>     
> org.datanucleus.TransactionImpl.internalPreCommit(TransactionImpl.java:379)
>     org.datanucleus.TransactionImpl.commit(TransactionImpl.java:268)
>     org.datanucleus.api.jdo.JDOTransaction.commit(JDOTransaction.java:98)
>     
> org.apache.sentry.provider.db.service.persistent.TransactionManager.executeTransaction(TransactionManager.java:113)
>     
> org.apache.sentry.provider.db.service.persistent.SentryStore.retrieveFullPermssionsImage(SentryStore.java:2225)
>     
> org.apache.sentry.hdfs.PermImageRetriever.retrieveFullImage(PermImageRetriever.java:56)
>     
> org.apache.sentry.hdfs.PermImageRetriever.retrieveFullImage(PermImageRetriever.java:40)
>     
> org.apache.sentry.hdfs.DBUpdateForwarder.getAllUpdatesFrom(DBUpdateForwarder.java:85)
>     
> org.apache.sentry.hdfs.SentryPlugin.getAllPermsUpdatesFrom(SentryPlugin.java:178)
>     
> org.apache.sentry.hdfs.SentryHDFSServiceProcessor.get_all_authz_updates_from(SentryHDFSServiceProcessor.java:48)
>     
> org.apache.sentry.hdfs.service.thrift.SentryHDFSService$Processor$get_all_authz_updates_from.getResult(SentryHDFSService.java:403)
>     
> org.apache.sentry.hdfs.service.thrift.SentryHDFSService$Processor$get_all_authz_updates_from.getResult(SentryHDFSService.java:388)
>     org.apache.thrift.ProcessFunction.process(ProcessFunction.java:39)
>     org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:39)
>     
> org.apache.sentry.hdfs.SentryHDFSServiceProcessorFactory$ProcessorWrapper.process(SentryHDFSServiceProcessorFactory.java:47)
>     
> org.apache.thrift.TMultiplexedProcessor.process(TMultiplexedProcessor.java:123)
>     
> org.apache.thrift.server.TThreadPoolServer$WorkerProcess.run(TThreadPoolServer.java:286)
>     
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
>     
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
>     java.lang.Thread.run(Thread.java:745)



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