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From "Ryan Rawson" <ryano...@gmail.com>
Subject Re: Review Request: Timestamp based optimization for selecting the StoreFiles to be used in a Scan
Date Mon, 12 Jul 2010 20:09:10 GMT

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there are a number of intenting issues, HBase uses a 2 space base and a 4 space hanging indent
standard.  Also we space separate the outside of our braces, so it is "if (" not "if(".  The
interior of the braces are not to be spaced, eg: "(foo)" not "( foo )".  I am also seeing
a large number of trailing whitespace, you should be able to set your editor to automatically
remove that for you. They show up as red blocks on the code review.  

It also appears that this patch includes pieces from other bloom related patches... those
code snippets should be removed from this patch.


    This doesnt appear to be germane to the issue at hand.  It shouldn't appear in this patch.


    indentation, looks like there might be a tab here


    is this idiomatic? I dont think I've seen this particular pattern before?


    This doesnt seem germane to the issue at hand... Can we not do this here?

- Ryan

On 2010-07-09 15:28:53, Pranav Khaitan wrote:
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> http://review.hbase.org/r/257/
> -----------------------------------------------------------
> (Updated 2010-07-09 15:28:53)
> Review request for hbase, Nicolas, Jonathan Gray, Karthik Ranganathan, and Kannan Muthukkaruppan.
> Summary
> -------
> Every memstore and store file will have a minimum and maximum timestamp associated with
it. If the range of timestamps we are searching for doesn't overlap with the range for a particular
file, we can skip searching it and save time.
> Would significantly improve the performance for timestamp range queries. Particularly
useful when most of the reads are for recent entries and the older files can be safely skipped.

> Addresses HBASE-2265 JIRA. 
> This diff includes fixing some minor bugs like KeyValueHeap used to throw an uncaught
exception when size of scanner set was zero. 
> Internal review done by Jonathan and Kannan.
> This addresses bug HBASE-2265.
>     http://issues.apache.org/jira/browse/HBASE-2265
> Diffs
> -----
>   trunk/src/main/java/org/apache/hadoop/hbase/KeyValue.java 959782 
>   trunk/src/main/java/org/apache/hadoop/hbase/regionserver/KeyValueHeap.java 959782 
>   trunk/src/main/java/org/apache/hadoop/hbase/regionserver/MemStore.java 959782 
>   trunk/src/main/java/org/apache/hadoop/hbase/regionserver/Store.java 959782 
>   trunk/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFile.java 959782 
>   trunk/src/main/java/org/apache/hadoop/hbase/regionserver/StoreFileScanner.java 959782

>   trunk/src/main/java/org/apache/hadoop/hbase/regionserver/StoreScanner.java 959782 
>   trunk/src/main/java/org/apache/hadoop/hbase/regionserver/TimeRangeTracker.java PRE-CREATION

>   trunk/src/test/java/org/apache/hadoop/hbase/client/TestMultipleTimestamps.java PRE-CREATION

>   trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestMemStore.java 960082 
>   trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestStore.java 959782 
>   trunk/src/test/java/org/apache/hadoop/hbase/regionserver/TestStoreFile.java 959782

> Diff: http://review.hbase.org/r/257/diff
> Testing
> -------
> All existing JUnit tests run successfully. More JUnit tests for Memstore, StoreFile and
Store added to test correctness with multiple timestamps.
> Conducted a test to measure the extra time required to keep track of min and max timestamps
while writing KeyValues.  The comparison was done by entering 1 Million KeyValues into memstore
ten times with and without timestamp tracking and then taking the average time for each of
them.  WAL was disabled and no flushing was done during this test to minimize overheads. The
average time taken for entering 1M KeyValues into memstore without keeping track of timestamp
was 13.44 seconds while the average time when keeping track of timestamps was 13.45 seconds.
This shows that no significant overhead has been added while keeping track of timestamps.
> Thanks,
> Pranav

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