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From Ceki Gülcü <c...@qos.ch>
Subject Re: BufferSize always the same
Date Thu, 02 Oct 2003 15:16:13 GMT

I should have verified for typos before posting my reply. Corrections below.

At 05:10 PM 10/2/2003 +0200, you wrote:
>Well, in Java IO there are buffers and buffers.
>
>Even if you do *not* set the bufferedIO option in FileAppender, that is if 
>bufferedIO is set to false, writing to the file is buffered. 
>FileOutputStream is buffered.

I mean to say that FileOutputStream *always* buffers writes to the hard 
disk independently of FileAppender's bufferedIO option.

>If you set the bufferedIO option, FileAppender will buffer String 
>(unicode) to stream conversions, FileOutputStream will continue to buffer 
>writes to physical media.

FileAppender's bufferedIO option only saves String (unicode) to stream 
conversions.

>At 09:26 AM 10/2/2003 -0500, Pascal Rheaume (QC/EMC) wrote:
>>Hi,
>>
>>I'm using a custom FileAppender with buffered io because speed is really 
>>important for me. I have amazing improvement over not buffered io, so I 
>>would like to keep it buffered. I'm able to live with a small lost of 
>>logging at the end due to the buffer that has not been emptied. And if 
>>I'm correct, the default size for the buffer is 8kb. For me, 8kb is too 
>>big so I want to reduce this size.
>
>Yes, the default buffer for buffered for BufferedWriter is 8KB.

Yes, the default buffer for BufferedWriter (created by FileAppender when 
bufferedIO=yes) is 8KB.

>I am surprised to learn that the bufferedIO option yields in "an amazing 
>improvement". Which JDK version are you using?
>
>
>>Here is my problem: whatever number I put in the BufferSize parameter, it 
>>is ALWAYS a 8kb buffer. The final size of my log file is 8kb or less than 
>>the log file I would have for the same operations sequence in a not 
>>buffered IO.
>
>I fail to not understand the above sentence.
>
>
>>I set the ImmediateFlush parameter to false and the BufferedIO parameter 
>>to true. So, anybody has an idea on what could be the source of my 
>>problem here? I really don' get it!
>>
>>I have a secondary question: that BufferSize parameter, is it a size in 
>>kb or a size in number of log statements?
>
>It size in bytes.

The size is in bytes.


>>  Because, if what I read was correct, in AsyncAppender, BufferSize is a 
>> number of log statements.
>
>Correct.  In AsyncAppender, BufferSize is the number of log statements.
>
>>Pascal
>
>--
>Ceki Gülcü

-- 
Ceki Gülcü

      For log4j documentation consider "The complete log4j manual"
      ISBN: 2970036908 http://www.qos.ch/shop/products/clm_t.jsp

      import org.apache.Facetime;
      ApacheCon US 2003, 18-21 November http://apachecon.com/



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