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From Mike Matrigali <mikem_...@sbcglobal.net>
Subject Re: Modified UTF-8 or UTF-16 for temporary Clobs?
Date Wed, 23 May 2007 16:35:10 GMT


Oystein Grovlen - Sun Norway wrote:
> Mike Matrigali wrote:
>  > What is the expected usage pattern for an update on a clob that uses
> 
>> these "temporary" clobs?  What is the usual input format, what is the
>> usual output format?  Do you expect more than one update usually?  Does
>> an update have to rewrite the end of the file on and shrink or expand of
>> a middle of the clob?
> 
> 
> In client/server, a single update may cause a sequence of updates 
> against the embedded driver.  This is because the locator implementation 
>  uses a stored procedure to perform the update, and Derby does not 
> support Clob as procedure parameters.  To overcome that, the Blob is 
> split into segments of max size for VARCHAR.  Hence, it is important at 
> the overhead of positioning is not big in these cases.  One way to 
> optimize for this would be to remember the end position from last write.
> 
How do these calls relate to calls to the store code for the update?  Is
there still one call to store or one per segment?


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