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From Jean-Daniel Cryans <jdcry...@apache.org>
Subject Re: Reading while appending in 0.21
Date Tue, 12 Jan 2010 01:33:43 GMT
Thanks for the answer Konstantin, good to know. I also see that the
commenter doesn't seem pleased with the fact that the file has to be
reopened ;)

So basically what I wrongly expected was a tailing feature. Searches
in Jira don't give me a hit, would it make sense to open one?

In the mean time, I'm ok with recreating the reader.

Thx,

J-D

On Mon, Jan 11, 2010 at 5:15 PM, Konstantin Boudnik <cos@yahoo-inc.com> wrote:
> Jean,
>
> I believe this is how it has been intended to work. If you take a look at
> the test src/test/hdfs/org/apache/hadoop/hdfs/TestHFlush.java in HDFS
> workspace you'll a comment on this particular aspect in the line 124.
>
> Hope it helps,
>  Cos
>
> On 1/11/10 16:42 , Jean-Daniel Cryans wrote:
>>
>> Hi,
>>
>> I'm trying to use the new hflush function from 0.21 so that a
>> SequenceFile.Reader could read edits from a SequenceFile.Writer after
>> a signal on a Condition. If I:
>>
>> create the Writer
>> append entries
>> hflush
>> create the Reader
>> next() through the entries
>>
>> It works fine. But after that if I only next(), using the same reader,
>> after appending/hflush I won't see the new edits. But, if I create a
>> new Reader after calling hflush, it works fine.
>>
>> So this does not work:
>>
>> create the Writer
>> append entries
>> hflush
>> create the Reader
>> next() through the entries
>> append entries
>> hflush
>> next() through the entries
>> append entries
>> hflush
>> next() through the entries
>>
>> This does:
>>
>> create the Writer
>> append entries
>> hflush
>> create the Reader
>> next() through the entries
>> append entries
>> hflush
>> create a new Reader
>> seek
>> next() through the entries
>>
>> Is that the intended behavior?
>>
>> Thx!
>>
>> J-D
>

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