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https://issues.apache.org/jira/browse/HBASE-3073?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12917128#action_12917128
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ryan rawson commented on HBASE-3073:
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this does indeed fix HBASE-1937, and HBASE-2753 is in progress under it's own
commit. At that time we can make raw/sorted do the same thing (just return
'kvs').
This fixes HBASE-1937 by introducing the getColumnLatest() which returns a
KeyValue which the user can call getTimestamp() on. Instead of creating Result
API calls for every conceivable thing a user might want to do, let's just
expose the KeyValue which has a rich API for doing all sorts of things, such as
getting various fields (timestamp, qualifier, field, row, value) and comparison.
I need to do a bit more perf testing and then I will clean up those javadocs.
> New APIs for Result, faster implementation for some calls
> ---------------------------------------------------------
>
> Key: HBASE-3073
> URL: https://issues.apache.org/jira/browse/HBASE-3073
> Project: HBase
> Issue Type: Bug
> Affects Versions: 0.89.20100924
> Reporter: ryan rawson
> Assignee: ryan rawson
> Fix For: 0.90.0
>
> Attachments: HBASE-3073.txt
>
>
> Our existing API for Result hasn't been given much love in the last year. In
> the mean time, inefficiencies in the existing implementation have come to
> light, causing issues with benchmarks. Furthermore, some people are finding
> the API both difficult to use as well as not useful enough (See: HBASE-1937).
> I propose the following new APIs:
> public List<KeyValue> getColumn(byte [] family, byte [] qualifier);
> public KeyValue getColumnLatest(byte [] family, byte [] qualifier);
> The implementation of these use a binary search on the underlying kvs array
> (which is sorted). I also have new implementations for
> public boolean containsColumn(byte [] family, byte [] qualifier);
> public byte [] getValue(byte [] family, byte [] qualifier);
> Which in the small case run faster, but in the big case seem to run a bit
> slower. That is if you call getValue() 10 times for a Result it will be
> faster with the new implementation, but if you call getValue() 100 times for
> the same Result it is faster using the old implementation. My tests
> indicated about 10% slower on 'getValue' 100x with an overall 1000x iteration
> on 1000 different Result objects. Considering most people use getValue() to
> retrieve named columns and iteration when the qualifier list is unknown I
> think this is a reasonable trade off.
> Along with the new API, there is a recommendation to use raw() to get the
> list of KeyValue objects for iteration. This increases the visibility of
> KeyValue, and also is much faster to iterate (4.9 times on my mini benchmark,
> 100 columns per Result, redone 1000 times on different Result objects).
> Given my recent major speed boost by changing YCSB to use the raw()
> interface, I think that this is a must have for 0.90.
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