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https://issues.apache.org/jira/browse/HDFS-6735?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14223901#comment-14223901
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Lars Hofhansl commented on HDFS-6735:
-------------------------------------
The remaining findbugs warning is due to cachingStrategy. I am 100% sure that
the locking is correct, every single reference to cachingStrategy is guarded by
the infoLock.
This should good to go (happy to squash the bogus findbugs warning if somebody
has a suggestion how).
The findbugs website states this for IS2_INCONSISTENT_SYNC:
{quote}
Note that there are various sources of inaccuracy in this detector; for
example, the detector cannot statically detect all situations in which a lock
is held. Also, even when the detector is accurate in distinguishing locked vs.
unlocked accesses, the code in question may still be correct.
{quote}
> A minor optimization to avoid pread() be blocked by read() inside the same
> DFSInputStream
> -----------------------------------------------------------------------------------------
>
> Key: HDFS-6735
> URL: https://issues.apache.org/jira/browse/HDFS-6735
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: hdfs-client
> Affects Versions: 3.0.0
> Reporter: Liang Xie
> Assignee: Liang Xie
> Attachments: HDFS-6735-v2.txt, HDFS-6735-v3.txt, HDFS-6735-v4.txt,
> HDFS-6735-v5.txt, HDFS-6735.txt
>
>
> In current DFSInputStream impl, there're a couple of coarser-grained locks in
> read/pread path, and it has became a HBase read latency pain point so far. In
> HDFS-6698, i made a minor patch against the first encourtered lock, around
> getFileLength, in deed, after reading code and testing, it shows still other
> locks we could improve.
> In this jira, i'll make a patch against other locks, and a simple test case
> to show the issue and the improved result.
> This is important for HBase application, since in current HFile read path, we
> issue all read()/pread() requests in the same DFSInputStream for one HFile.
> (Multi streams solution is another story i had a plan to do, but probably
> will take more time than i expected)
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