hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Lars Hofhansl (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-10015) Replace intrinsic locking with explicit locks in StoreScanner
Date Tue, 26 Nov 2013 21:11:39 GMT

     [ https://issues.apache.org/jira/browse/HBASE-10015?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Lars Hofhansl updated HBASE-10015:
----------------------------------

       Resolution: Fixed
    Fix Version/s: 0.94.15
                   0.96.1
                   0.98.0
     Hadoop Flags: Reviewed
           Status: Resolved  (was: Patch Available)

Committed to all branches.

Interestingly now I find that for tall tables region.getCoprocessorHost().postScannerFilterRow
takes the new top spot.
(with a sampling profiler)

> Replace intrinsic locking with explicit locks in StoreScanner
> -------------------------------------------------------------
>
>                 Key: HBASE-10015
>                 URL: https://issues.apache.org/jira/browse/HBASE-10015
>             Project: HBase
>          Issue Type: Bug
>            Reporter: Lars Hofhansl
>            Assignee: Lars Hofhansl
>              Labels: performance
>             Fix For: 0.98.0, 0.96.1, 0.94.15
>
>         Attachments: 10015-0.94-lock.txt, 10015-0.94-new-sample.txt, 10015-0.94-v2.txt,
10015-0.94-v3.txt, 10015-0.94-v4.txt, 10015-0.94-withtest.txt, 10015-0.94.txt, 10015-trunk-lock.txt,
10015-trunk-v2.txt, 10015-trunk-v3.txt, 10015-trunk-v4.txt, 10015-trunk-v4.txt, 10015-trunk-v4.txt,
10015-trunk.txt, TestLoad.java
>
>
> Did some more profiling (this time with a sampling profiler) and StoreScanner.peek()
showed up a lot in the samples. At first that was surprising, but peek is synchronized, so
it seems a lot of the sync'ing cost is eaten there.
> It seems the only reason we have to synchronize all these methods is because a concurrent
flush or compaction can change the scanner stack, other than that only a single thread should
access a StoreScanner at any given time.
> So replaced updateReaders() with some code that just indicates to the scanner that the
readers should be updated and then make it the using thread's responsibility to do the work.
> The perf improvement from this is staggering. I am seeing somewhere around 3x scan performance
improvement across all scenarios.
> Now, the hard part is to reason about whether this is 100% correct. I ran TestAtomicOperation
and TestAcidGuarantees a few times in a loop, all still pass.
> Will attach a sample patch.



--
This message was sent by Atlassian JIRA
(v6.1#6144)

Mime
View raw message