[seek-dev] cache post-relational database
Bertram Ludaescher
ludaesch at sdsc.edu
Fri Nov 5 05:45:37 PST 2004
Matt, Serguei, Shawn:
Also related to our discussion yesterday is this paper:
A Comprehensive XQuery to SQL Translation using Dynamic Interval Encoding
ABSTRACT The W3C XQuery language recommendation, based on a
hierarchical and ordered document model, supports a wide variety of
constructs and use cases. There is a diversity of approaches and
strategies for evaluating XQuery expressions, in many cases only
dealing with limited subsets of the language. In this paper we
describe an implementation approach that handles XQuery with
arbitrarily-nested FLWR expressions, element constructors and built-in
functions (including structural comparisons). Our proposal maps an
XQuery expression to a single equivalent SQL query using a novel
dynamic interval encoding of a collection of XML documents as
relations, augmented with information tied to the query evaluation
environment. The dynamic interval technique enables (suitably
enhanced) relational engines to produce predictably good query plans
that do not restrict the use of sort-merge join query operators. The
benefits are realized despite the challenges presented by intermediate
results that create arbitrary documents and the need to preserve
document order as prescribed by semantics of XQuery. Finally, our
experimental results demonstrate that (native or relational) XML
systems can benefit from the above technique to avoid a quadratic
scale up penalty that effectively prevents the evaluation of nested
FLWR expressions for large documents.
Here is the paper: http://db.uwaterloo.ca/~david/papers-sigmod03.pdf
Bertram
>>>>> "SK" == Serguei Krivov <Serguei.Krivov at uvm.edu> writes:
SK>
SK> Dear All,
SK> The InterSystem Corporation http://www.intersystems.com/cache/
SK> claims that CACHE database has far better performance comparing to
SK> Oracle.
SK> It has native XML mapping and a bunch of other useful features.
SK>
SK> Does anyone have any opinion on pros vs. cons of their multidimensional
SK> arrays storage technology,
SK> described eg. At
SK> http://www.intersystems.com/cache/technology/techguide/index.html ???
SK>
SK> Thanks,
SK> Serguei
SK>
SK>
SK>
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SK> <div class=Section1>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
SK> font-family:Arial'>Dear All,<o:p></o:p></span></font></p>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
SK> font-family:Arial'>The <span class=SpellE>InterSystem</span> Corporation <a
SK> href="http://www.intersystems.com/cache/">http://www.intersystems.com/cache/</a><o:p></o:p></span></font></p>
SK>
SK> <p class=MsoNormal><span class=GramE><font size=2 face=Arial><span
SK> style='font-size:10.0pt;font-family:Arial'>claims</span></font></span><font
SK> size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> that CACHE
SK> database<span style='mso-spacerun:yes'> </span>has far better performance
SK> <span style='mso-spacerun:yes'> </span>comparing to Oracle. <o:p></o:p></span></font></p>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
SK> font-family:Arial'>It has native <span class=GramE>XML <span
SK> style='mso-spacerun:yes'> </span>mapping</span> and a bunch of other useful
SK> features.<o:p></o:p></span></font></p>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
SK> font-family:Arial'><o:p> </o:p></span></font></p>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
SK> font-family:Arial'>Does anyone have any opinion on pros vs. cons of their multidimensional
SK> arrays storage <span style='mso-spacerun:yes'> </span>technology,<o:p></o:p></span></font></p>
SK>
SK> <p class=MsoNormal><span class=GramE><font size=2 face=Arial><span
SK> style='font-size:10.0pt;font-family:Arial'>described</span></font></span><font
SK> size=2 face=Arial><span style='font-size:10.0pt;font-family:Arial'> <span
SK> class=SpellE>eg</span>. </span></font><font size=2 face=Arial><span lang=DA
SK> style='font-size:10.0pt;font-family:Arial;mso-ansi-language:DA'>At http://www.intersystems.com/cache/technology/techguide/index.html<span
SK> style='mso-spacerun:yes'> </span>???<o:p></o:p></span></font></p>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span lang=DA style='font-size:10.0pt;
SK> font-family:Arial;mso-ansi-language:DA'><o:p> </o:p></span></font></p>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
SK> font-family:Arial'>Thanks,<o:p></o:p></span></font></p>
SK>
SK> <p class=MsoNormal><font size=2 face=Arial><span style='font-size:10.0pt;
SK> font-family:Arial'>Serguei<o:p></o:p></span></font></p>
SK>
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SK>
SK> <p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
SK> 12.0pt'><o:p> </o:p></span></font></p>
SK>
SK> </div>
SK>
SK> </body>
SK>
SK> </html>
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