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From TomohitoNakayama <tomon...@basil.ocn.ne.jp>
Subject Re: [jira] Commented: (DERBY-326) Improve streaming of large objects for network server and client
Date Sat, 29 Apr 2006 06:14:31 GMT

Thank you for your cooperation !

About 1), I will add comment to the OutBufferedStream.java

About 2),
I think description of configuration property 
derby.drda.streamOutBufferSize should be added to next,
as rendered to

I will add subtask of DERBY-326 for patch of documentation.

Best regards.

Bryan Pendleton (JIRA) wrote:

>    [ http://issues.apache.org/jira/browse/DERBY-326?page=comments#action_12377035 ] 
>Bryan Pendleton commented on DERBY-326:
>As you know, I have studied this patch multiple times; I think it is excellent.
>Two thoughts, if you have not yet committed the patch:
>1) It would be nice if you could add some comments to OutBufferedStream.java indicating
the purpose of this test.
>2) Should we add some documentation about the new configuration property derby.drda.streamOutBufferSize?
>Thank you very much for all the great work on this issue!
>>Improve streaming of large objects for network server and client
>>         Key: DERBY-326
>>         URL: http://issues.apache.org/jira/browse/DERBY-326
>>     Project: Derby
>>        Type: Improvement
>>  Components: Network Client, Performance, Network Server
>>    Reporter: Kathey Marsden
>>    Assignee: Tomohito Nakayama
>> Attachments: ClobTest.zip, DERBY-326.patch, DERBY-326_2.patch, DERBY-326_3.patch,
DERBY-326_4.patch, DERBY-326_5.patch, DERBY-326_5_indented.patch, DERBY-326_6.patch, DERBY-326_7.patch,
>>Currently the stream writing  methods in network server and client require a  length
parameter. This means that we have to get the length of the stream before sending it. For
example in network server in EXTDTAInputStream we have to use getString and getbytes() instead
of getCharacterStream and getBinaryStream so that we can get the  length.
>>SQLAM Level 7 provides for the enhanced LOB processing to allow streaming without
indicating the length, so, the writeScalarStream methods in
>>network server DDMWriter.java and network client Request.java can be changed to not
require a length.
>>Code inspection of these methods seems to indicate that while the length is never
written it is used heavily in generating the DSS. One strange thing is that it appears on
error, the stream is padded out to full length with zeros, but an actual exception is never
sent.  Basically I think perhaps these methods need to be rewritten from scratch based on
the spec requirements for lobs.
>>After the writeScalarStream methods have been changed, then EXTDAInputStream can be
changed to properly stream LOBS. See TODO tags in this file for more info.  I am guessing
similar optimizations available in the client as well, but am not sure where that code is.


        Tomohito Nakayama



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