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https://issues.apache.org/jira/browse/HBASE-10060?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Lars Hofhansl updated HBASE-10060:
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Attachment: 10060-trunk-v2.txt
This fixed TestAtomicOperation, by always initializing syncObject, even when it
is later overwritten with the resp RegionScannerImpl in the normal scanner case.
This is correct, because when it matters, we always sync on the
RegionScannerImpl methods.
Works, but is a bit fragile.
> Unsynchronized scanning
> -----------------------
>
> Key: HBASE-10060
> URL: https://issues.apache.org/jira/browse/HBASE-10060
> Project: HBase
> Issue Type: Bug
> Reporter: Lars Hofhansl
> Attachments: 10060-trunk-v2.txt, 10060-trunk.txt
>
>
> HBASE-10015 has some lengthy discussion. The solution there ended up
> replacing synchronized with ReentrantLock, which - somewhat surprisingly -
> yielded a non-trivial improvement for tall tables.
> The goal should be to avoid locking in StoreScanner at all. StoreScanner is
> only accessed by a single thread *except* when we have a concurrent flush or
> a compaction, which is rare (we'd acquire and release the lock millions of
> times per second, and compact/flush a few time an hour at the most).
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