TLC XQuery timings and XMark size factors

[Michael Kay]

> The 
> authors say they tested 'size factors from 0.1 (approx. 67MB 
> combined data plus indexes space) up to factor 5 (3.5GB 
> combined data plus indexes space), and I'm wondering if 
> anyone who has read (or cares to read) that paper can tell me 
> if they understand how those sizes were reached?
> 
> The sizes I'm seeing from xmlgen don't seem to map to the 
> same sizes the authors list.  A size factor of 0.1 comes out 
> to just under 12MB of data.

Generally, the size occupied by XML in searchable form will be larger than
the size of the raw lexical XML. An expansion factor of about 5 is quite
good; if you build lots of indexes, or use a DOM, then it can be a lot
higher. I would assume they are quoting the space occupied by the searchable
XML (I haven't read the paper to see whether that's on disk or in memory).

Michael Kay
http://www.saxonica.com/