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From Karl Weber <karl.webe...@googlemail.com>
Subject Re: Reclaim unused space, but how exactly?
Date Sun, 06 Mar 2016 17:57:07 GMT
Hi Bryan,

thank you for your answer. My problem is the following: You may think about a 
table with a column (among others) that contains a large amount of 
unstructured data. These data will to a large extent (but perhaps not 
completely) be replaced by structured data (in some user defined data type) in 
another column. This will reduce the space requirements considerably for each 
particular row. This conversion of the data will be done only once and also 
require the addition of one new column to the table in question. After this 
conversion, the newly added rows will already have the data structured.

So my question is about what to do after this conversion in order to have no 
disk space wasted.

Am Sonntag, 6. März 2016, 08:53:10 schrieb Bryan Pendleton:
> > I want to make the unused space availabe to derby for the insertion of new
> > rows. It should be optinal to give unused space back to the OS. In order
> > to do so, I have to use some system utility.
> I'm not totally sure whether the 5th word in the above line is "optional"
> or "optimal".

The word is optional. The point is, that the number of rows will further 
increase, so there seems to be no point in giving the space back to the OS 
after the conversion, derby will need this space later anyway. I just want to 
make sure that disk space will be used efficiently after the conversion.

With kind regards

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