[ http://issues.apache.org/jira/browse/DERBY-326?page=all ]
Tomohito Nakayama updated DERBY-326:
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Comment: was deleted
> 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 Server, Network Client, Performance
> Reporter: Kathey Marsden
> Assignee: Tomohito Nakayama
> Attachments: DERBY-326.patch, DERBY-326_2.patch, DERBY-326_3.patch,
> DERBY-326_4.patch, DERBY-326_5.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.
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