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https://issues.apache.org/jira/browse/HBASE-1938?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13071484#comment-13071484
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stack commented on HBASE-1938:
------------------------------
On 20110726_1938_MemStore.patch:
FYI, in future, just remove code rather than commment it out: i.e. +
//long readPoint = ReadWriteConsistencyControl.getThreadReadPoint();
The 'thenext' data member looks fine to me. Worst that could happen is that we
lag the read point slightly though unlikely ('theNext' ain't best name but I
see you are just taking the old local variable name so not your malnaming... no
worries).
Any chance of our calling a 'next' without doing a 'seek' first (or a reseek)?
Am worried we'd trip on a null theNext.
If seek has a synchronized, yeah, reseek should too -- good one.
I'm good with committing this. We have a bunch of tests that should vomit if
stuff comes back out of order or not what we expect (If this does prove to
break things, then we are lacking key coverage and lets address it then).
I'll let it hang out a day. Someone else might have an opinion in here.
> Make in-memory table scanning faster
> ------------------------------------
>
> Key: HBASE-1938
> URL: https://issues.apache.org/jira/browse/HBASE-1938
> Project: HBase
> Issue Type: Improvement
> Components: performance
> Reporter: stack
> Assignee: stack
> Priority: Blocker
> Attachments: 20110726_1938_KeyValueSkipListSet.patch,
> 20110726_1938_MemStore.patch, 20110726_1938_MemStoreScanPerformance.java,
> MemStoreScanPerformance.java, MemStoreScanPerformance.java,
> caching-keylength-in-kv.patch, test.patch
>
>
> This issue is about profiling hbase to see if I can make hbase scans run
> faster when all is up in memory. Talking to some users, they are seeing
> about 1/4 million rows a second. It should be able to go faster than this
> (Scanning an array of objects, they can do about 4-5x this).
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