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https://issues.apache.org/jira/browse/HBASE-20403?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16518684#comment-16518684
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Todd Lipcon commented on HBASE-20403:
-------------------------------------
I'm guessing maybe this is partially due to HBASE-17917. It seems there used to
be a lock {{streamLock}} inside HFileBlock which prevented multiple threads
from doing non-positional reads on top of each other. That patch basically
removed usage of this lock except for in "unbuffer", but now it no longer
really protects anything (except perhaps multiple unbuffers from each other?).
I'm not sure if there are other cases where non-preads are used but worth
auditing to make sure my patch here isn't too shallow.
Also worth noting that moving from streaming to positional probably means that
the prefetching will be slower.
> Prefetch sometimes doesn't work with encrypted file system
> ----------------------------------------------------------
>
> Key: HBASE-20403
> URL: https://issues.apache.org/jira/browse/HBASE-20403
> Project: HBase
> Issue Type: Bug
> Affects Versions: 2.0.0-beta-2
> Reporter: Umesh Agashe
> Assignee: Todd Lipcon
> Priority: Major
> Fix For: 3.0.0
>
> Attachments: hbase-20403.patch
>
>
> Log from long running test has following stack trace a few times:
> {code}
> 2018-04-09 18:33:21,523 WARN
> org.apache.hadoop.hbase.io.hfile.HFileReaderImpl: Prefetch
> path=hdfs://ns1/hbase/data/default/IntegrationTestBigLinkedList_20180409172704/35f1a7ef13b9d327665228abdbcdffae/meta/9089d98b2a6b4847b3fcf6aceb124988,
> offset=36884200, end=231005989
> java.lang.IllegalArgumentException
> at java.nio.Buffer.limit(Buffer.java:275)
> at
> org.apache.hadoop.hdfs.ByteBufferStrategy.readFromBlock(ReaderStrategy.java:183)
> at org.apache.hadoop.hdfs.DFSInputStream.readBuffer(DFSInputStream.java:705)
> at
> org.apache.hadoop.hdfs.DFSInputStream.readWithStrategy(DFSInputStream.java:766)
> at org.apache.hadoop.hdfs.DFSInputStream.read(DFSInputStream.java:831)
> at
> org.apache.hadoop.crypto.CryptoInputStream.read(CryptoInputStream.java:197)
> at java.io.DataInputStream.read(DataInputStream.java:149)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock.readWithExtra(HFileBlock.java:762)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl.readAtOffset(HFileBlock.java:1559)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl.readBlockDataInternal(HFileBlock.java:1771)
> at
> org.apache.hadoop.hbase.io.hfile.HFileBlock$FSReaderImpl.readBlockData(HFileBlock.java:1594)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderImpl.readBlock(HFileReaderImpl.java:1488)
> at
> org.apache.hadoop.hbase.io.hfile.HFileReaderImpl$1.run(HFileReaderImpl.java:278)
> at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
> at java.util.concurrent.FutureTask.run(FutureTask.java:266)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180)
> at
> java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
> at java.lang.Thread.run(Thread.java:748)
> {code}
> Size on disk calculations seem to get messed up due to encryption. Possible
> fixes can be:
> * if file is encrypted with FileStatus#isEncrypted() and do not prefetch.
> * document that hbase.rs.prefetchblocksonopen cannot be true if file is
> encrypted.
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