BaseX-Talk

basex-talk@mailman.uni-konstanz.de

13 participants
5244 discussions

Fwd: Insert position of attributes
by Jan Vlčinský (CAD) 04 Dec '11

04 Dec '11

Hi Regarding the (not existent) requirement for attribute order: In http://www.w3.org/TR/2008/REC-xml-20081126/#sec-starttags there is a note "Note that the order of attribute specifications in a start-tag or empty-element tag is not significant." And my recommendation is: Do not put any extra requirements to any XML, which is not really needed. In case of attributes, you may and up promissing your consumers that the order of attributes will be as you define, and later you may have problems switching tools, which follow W3C recommendation, but not your extra promise. So the general advice is: keep your promises at minimum possible, it will easy work for you and also for your partners. The same often applies, when people start insisting on certain XML encoding, encoding or not encoding of special characters - all these requirements are more cosmetic then practical and often do originate from people, who do not understand the topic so well, but are well trained in the exercise "find three differences it those two pictures". Jan *Ing. Jan Vlčinský* CAD programy Slunečnicová 338/3, 734 01 Karviná Ráj, Czech Republic tel: +420-597 602 024; mob: +420-608 979 040 skype: janvlcinsky; GoogleTalk: jan.vlcinsky(a)gmail.com http://cz.linkedin.com/in/vlcinsky On 2 December 2011 18:46, Dave Glick <dglick(a)dracorp.com> wrote: > After a little more investigation of the XQuery Update standard, it looks > to me like BaseX is doing this right and the standard does not allow for > positioning of attribute insertions (unless there’s another approach I’ve > overlooked). In case anyone else has a similar question – all insert > operations involving attributes resolve to the function > upd:insertAttributes which does not allow for positioning. It appears as > though the modifiers “as first” and “as last” are ignored in the case of > attributes.**** > > ** ** > > I suppose this makes sense if the ordering of attributes in XML is > unimportant and undefined. Can anyone clarify what the XML/XDM standard has > to say on the topic of attribute ordering? It’s a little confusing because > many XML processors attempt to present attributes with some kind of > explicit ordering (as an example, see the .NET XmlAttributeCollection class > which allows programmatic insertion of attributes before/after a reference > attribute).**** > > ** ** > > Thanks (again),**** > > ** ** > > Dave**** > > ** ** > > *From:* Dave Glick > *Sent:* Friday, December 02, 2011 12:37 PM > *To:* basex-talk(a)mailman.uni-konstanz.de > *Subject:* Insert position of attributes**** > > ** ** > > How would one go about inserting an attribute at a specific position > (i.e., somewhere other than at the front of the attribute list)? I would > expect the following expression would do the trick: “insert node attribute > aname {'avalue'} as last into //XYZ” but it still inserts the attribute at > the front of the attribute list.**** > > ** ** > > By looking at the code in the InsertAttribute update primitive, I can see > that it’s hardcoded to insert at the front of the attribute list. Does this > mean that there is no way to control attribute insertion location? Does the > XQuery Update standard not allow such an update or is this a bug/oversight > on the part of BaseX?**** > > ** ** > > Thanks!**** > > ** ** > > Dave**** > > ** ** > > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk(a)mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > >

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cdata-section-elements collisions
by jidanni＠jidanni.org 04 Dec '11

04 Dec '11

declare option output:cdata-section-elements "description"; works great, except that I want it to work only on my //Folder/description's not my //Placemark/description's. I read http://www.w3.org/TR/2010/REC-xslt-xquery-serialization-20101214/index.html… and http://docs.basex.org/wiki/Serialization and no matter what I do...

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Hi! form Mongolia
by Tuguldur J 03 Dec '11

03 Dec '11

Dear Sir, My name is Tuguldur from Mongolia. I am database architecturer of CSMS. So i want to develop BaseX to Mongolian language so much. I'm finally done, but the one thing i can't change that application name of 7.0.3 "beta" to 7.0.3 /"бета хувилбар" in Mongolian/. If it is done, one international version may has done. so please how can i fix that own problem.I look forward to your reply. thank you. Yours sincerely Bayangol district, 7-25 Ulaanbaatar, Mongolia

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running server commands from a script?
by C. M. Sperberg-McQueen 02 Dec '11

02 Dec '11

From time to time, I find myself wanting to run BaseX server commands from a shell script. For example, if I have two or three documents I'd like to add to a database, it's easy enough to do so from the GUI interface, or from the interactive server prompt. But if it's five or ten documents (and even more so if it's a few hundred or a few thousand documents), entering the commands interactively can become tedious and error prone. When the files are available on the local file system, I can use wildcards and I can add a directory at a time. But when the files are on a remote server and identified by URI instead of file name, I guess that won't work. What I think I'm looking for is the ability to specify a sequence of BaseX server commands and have it run that sequence of commands -- or some other way of being able to specify a list of filenames or URIs and have them all added to a given database. For example CREATE DATABASE demo OPEN demo ADD http://example.com/docs/a.xml ADD http://example.com/docs/b.xml ADD http://example.com/docs/c.xml ADD http://example.com/docs/d.xml ADD http://example.com/docs/e.xml ... ADD http://example.com/docs/z.xml RENAME http://example.com/docs/ / # I'd use ADD to a.xml http://example.com/docs/a.xml, but # that doesn't seem to have the effect I expect. But # RENAME works for what I need There is certainly a lot of BaseX documentation I have not read, but I have not found any mention of this kind of thing. Have I overlooked it? One technique that I guess would work would be to exploit the new REST interface (very nice, by the way!) and write a bash script that went something like this: curl http://localhost:8984/rest?command=CREATE+DATABASE+demo curl http://localhost:8984/rest/demo?command=ADD+http://example.com/docs/a.xml curl http://localhost:8984/rest/demo?command=ADD+http://example.com/docs/b.xml curl http://localhost:8984/rest/demo?command=ADD+http://example.com/docs/c.xml curl http://localhost:8984/rest/demo?command=ADD+http://example.com/docs/d.xml curl http://localhost:8984/rest/demo?command=ADD+http://example.com/docs/e.xml ... curl http://localhost:8984/rest/demo?command=ADD+http://example.com/docs/z.xml curl http://localhost:8984/rest/demo?command=RENAME+http://example.com/docs/+/ or rather CURL="curl --user X:secretpasswd" $CURL http://localhost:8984/rest?command=CREATE+DATABASE+demo etc. But if there is s nicer way to handle this case, I'd be glad to learn about it. Perhaps this is when I should buckle down and learn how to do this kind of thing with XQuery Update? Thanks! Michael Sperberg-McQueen -- **************************************************************** * C. M. Sperberg-McQueen, Black Mesa Technologies LLC * http://www.blackmesatech.com * http://cmsmcq.com/mib * http://balisage.net ****************************************************************

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Re: [basex-talk] Insert position of attributes
by Dave Glick 02 Dec '11

02 Dec '11

After a little more investigation of the XQuery Update standard, it looks to me like BaseX is doing this right and the standard does not allow for positioning of attribute insertions (unless there's another approach I've overlooked). In case anyone else has a similar question - all insert operations involving attributes resolve to the function upd:insertAttributes which does not allow for positioning. It appears as though the modifiers "as first" and "as last" are ignored in the case of attributes. I suppose this makes sense if the ordering of attributes in XML is unimportant and undefined. Can anyone clarify what the XML/XDM standard has to say on the topic of attribute ordering? It's a little confusing because many XML processors attempt to present attributes with some kind of explicit ordering (as an example, see the .NET XmlAttributeCollection class which allows programmatic insertion of attributes before/after a reference attribute). Thanks (again), Dave From: Dave Glick Sent: Friday, December 02, 2011 12:37 PM To: basex-talk(a)mailman.uni-konstanz.de Subject: Insert position of attributes How would one go about inserting an attribute at a specific position (i.e., somewhere other than at the front of the attribute list)? I would expect the following expression would do the trick: "insert node attribute aname {'avalue'} as last into //XYZ" but it still inserts the attribute at the front of the attribute list. By looking at the code in the InsertAttribute update primitive, I can see that it's hardcoded to insert at the front of the attribute list. Does this mean that there is no way to control attribute insertion location? Does the XQuery Update standard not allow such an update or is this a bug/oversight on the part of BaseX? Thanks! Dave

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Insert position of attributes
by Dave Glick 02 Dec '11

02 Dec '11

How would one go about inserting an attribute at a specific position (i.e., somewhere other than at the front of the attribute list)? I would expect the following expression would do the trick: "insert node attribute aname {'avalue'} as last into //XYZ" but it still inserts the attribute at the front of the attribute list. By looking at the code in the InsertAttribute update primitive, I can see that it's hardcoded to insert at the front of the attribute list. Does this mean that there is no way to control attribute insertion location? Does the XQuery Update standard not allow such an update or is this a bug/oversight on the part of BaseX? Thanks! Dave

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Writing output to multiple files
by Andreas Karpf 01 Dec '11

01 Dec '11

Dear BaseX Team! After several unfortunately unsuccessful trials & errors I am appealing to with a question which should be easy for you to answer, as I think it is pretty basic. I have a BaseX database filled up with thousands of different but equally structured xml-documents. What I want to do is to parse out necessary information and transform that into html files with distinct names. Actually I can parse out all the information I want but the output at the moment is just one huge html-file. The corresponding xquery looks something like this (I just left the parts in there which seem in my opinion relevant for my question, for real the whole xquery files is much much longer) declare option output:method "html"; (:Define word count function:) declare namespace functx = "http://www.functx.com"; declare function functx:word-count ($arg as xs:string?) as xs:integer {count(tokenize($arg,'\W+')[. != ''])}; let $items:= for $docitem in .//docitem where (:Text length (number of tokens):) for $text in $docitem/text where functx:word-count($text)<250 return (:Language :) for $language in $docitem/@xml:lang where $language="en" return <html> <body> <h3>{data($docitem/headline/text())}</h3> {$docitem/text/p/text()} <br>ID: {data($docitem/@itemid)}</br> <br>Word count:{functx:word-count($text)}</br> </body> </html> return file:write("//htmlfolder/file.html", $items) At the moment I just get all the parsed out elements in one if also well structured html file. What I however want would be multiple html files as output which have a filename like "itemid.htm" from $docitem/@itemid which is a distinct and exact identifier for all the xml files in the database. how can I achieve that. I have tried it with something like the following, but it won't work and I don't arrive to figue it out why: let $docitem:= .//docitem let $doc_id := data($docitem/@itemid) let $documentname := concat('//htmlfolder/', $doc_id, '.html') return file:write($documentname, $items) BaseX always tells me that "no sequences are allowed regarding $docitem/@itemid". What could be the problem there, or how could I solve this problem. I have tried several combinations because from what I have found on the web regarding my problem the solution should go into a similar direction. Would please somebody of you be so nice to help me with that. Every hint would be very much appreciated! Best regards, Andreas

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namespace limit?
by C. M. Sperberg-McQueen 01 Dec '11

01 Dec '11

Greetings! I've just downloaded BaseX 7.0.2, and was very happy to see the checkbox for "Skip corrupt (non-well-formed) files", since it makes it much much easier to create a BaseX database of the XSD test suite. But my attempt to build the database still fails with the message "idI001.xsd" (Line 2): Too many different namespaces (limit: 256). Since document idI001.xsd only declares 5 namespaces, I guess the 256-namespace limit is for the database, not for an individual document. Is there any way to ease the limit, or do I have to contemplate making multiple databases, each covering just part of the test suite? Thank you! Michael Sperberg-McQueen -- **************************************************************** * C. M. Sperberg-McQueen, Black Mesa Technologies LLC * http://www.blackmesatech.com * http://cmsmcq.com/mib * http://balisage.net ****************************************************************

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Re: [basex-talk] ajax and http server - cross-domain, jsonp or proxy?
by Maud Ingarao 30 Nov '11

30 Nov '11

Hello, The support of jsonp would be very welcomed here, since several projects on tge-adonis use or will use the basex.tge-adonis.fr/rest service... For now, I went on with the proxy solution : http://hyperdonat.tge-adonis.fr/basex/basex.html Cheers, Maud On Sat, Oct 22, 2011 at 12:07 AM, < basex-talk-request(a)mailman.uni-konstanz.de> wrote: > Send BaseX-Talk mailing list submissions to > basex-talk(a)mailman.uni-konstanz.de > > To subscribe or unsubscribe via the World Wide Web, visit > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > or, via email, send a message with subject or body 'help' to > basex-talk-request(a)mailman.uni-konstanz.de > > You can reach the person managing the list at > basex-talk-owner(a)mailman.uni-konstanz.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of BaseX-Talk digest..." > > > Today's Topics: > > 1. Re: Performance of Basex 7.0 XQuery execution (Leo W?rteler) > 2. Re: Problems in using BaseX REST server - > IncompatibleClassChangeError javax.ws.rs.core.Response$Status > does not implement the requested interface (Pushkaraj Thorat) > 3. Re: ajax and http server - cross-domain, jsonp or proxy? > (Godmar Back) > 4. Re: ajax and http server - cross-domain, jsonp or proxy? > (Michael Seiferle) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 21 Oct 2011 14:12:50 +0200 > From: Leo W?rteler <lw(a)basex.org> > To: Constantine Hondros <Constantine.Hondros(a)tomtom.com> > Cc: basex-talk <basex-talk(a)mailman.uni-konstanz.de> > Subject: Re: [basex-talk] Performance of Basex 7.0 XQuery execution > Message-ID: <4EA161C2.3060908(a)basex.org> > Content-Type: text/plain; charset=UTF-8; format=flowed > > Dear Constantine, > > Am 20.10.2011 09:44, schrieb Constantine Hondros: > > Of course, I am really interested in more useful queries such as: > > > > //tns:poi[not(tns:id = preceding-sibling::tns:poi/tns:id)] > > this query basically compiles to two nested loops, the outer one > iterating over //tns:poi and the inner one over all preceding-siblings. > So it has an O(n^2) runtime. > > > I guess what I am asking is ... while most XPath queries I run are quick > to resolve, anything using preceding::, preceding-sibling:: or following::, > following-sibling:: essentially runs too slowly to be workable - at least, > on my sample dataset with about 100K sibling children of the root element. > > Well, that's an extreme example, 100'000^2 is a huge number of nodes to > traverse. I performed some tests with > a) 10'000 sibling elements inside the root: > <root> > <item id="1"/> > <item id="2"/> > [...] > <item id="10000"/> > </root> > > and the query //item[not(preceding-sibling::*)] > > b) 10'000 nested elements: > <root> > <item id="1"> > <item id="2"> > [...] > <item id="10000"/> > [...] > </item> > </item> > </root> > > and the query //item[not(ancestor::*)] > > The timings I get are almost identical, replacing "preceding" with > "following" or "ancestor" with "descendant" doesn't change much. > > > So is this any sort of known issue? Should I be looking at any sort of > configuration options? Is there any way to profile the execution of the > Xpath? > > My guess is that the number of nodes on the *-sibling-axes is usually > much bigger than on the vertical axes, so an expensive algorithm gets > unusable earlier. > > To return to your example query, you could drastically reduce its > runtime by only traversing the database once, comparing each node only > to the nodes with unique tns:ids found before. I'll use a left fold [1][2]: > > fold-left( > function($seq, $x) { > if($seq/tns:id = $x/tns:id) then $seq > else ($seq, $x) > }, > (), > //tns:poi > ) > > If you're OK with using not-yet-standard XQuery extensions, a map [3] > instead of a sequence can potentially be even faster: > > let $map := > fold-left( > function($map, $x) { > let $key := $x/tns:id > return if(map:contains($map, $key)) then $map > else map:new(($map, map:entry($key, $x))) > }, > map:new(), > //tns:poi > ) > for $key in map:keys($map) > return $map($key) > > But this won't preserve the relative ordering of the results. > > Hope that helped, > Cheers Leo > __________ > > [1] http://www.w3.org/TR/xpath-functions-30/#func-fold-left > [2] http://en.wikipedia.org/wiki/Fold_%28higher-order_function%29 > [3] http://docs.basex.org/wiki/Map_Functions > > > ------------------------------ > > Message: 2 > Date: Sat, 22 Oct 2011 01:40:23 +0530 > From: Pushkaraj Thorat <pushkaraj.thorat.devl(a)gmail.com> > To: Rositsa Shadura <rositsa.shadura(a)uni-konstanz.de> > Cc: basex-talk(a)mailman.uni-konstanz.de > Subject: Re: [basex-talk] Problems in using BaseX REST server - > IncompatibleClassChangeError javax.ws.rs.core.Response$Status does > not > implement the requested interface > Message-ID: > <CAH5ngE_gf655mnLuTCAjStd2X1cmWKJQk8xYTErMyFv4QnMYeQ(a)mail.gmail.com > > > Content-Type: text/plain; charset="iso-8859-1" > > Thanks Rositsa! > It is bit late to reply, but indeed it is a good to know. > > Regards > Pushkaraj > > On Fri, Mar 4, 2011 at 3:01 AM, Rositsa Shadura < > rositsa.shadura(a)uni-konstanz.de> wrote: > > > Hi all, > > > > I've just managed accidentally to reproduce the error. I noticed that the > > class javax.ws.rs.core.Response.**Status is defined in both > > jsr311-api-1.0.jar and jersey-core-1.4.jar but only the class in the > > jersey-core JAR implements the interface > javax.ws.rs.core.Response.**StatusType. > > This is why it is important that the jersey-core JAR appears before the > > jsr311-api JAR in the classpath. When not the error occurs. > > > > Greetings, > > Rositsa > > > > > > On Thu, 20 Jan 2011 12:03:45 +0100, Michael Seiferle < > > michael.seiferle(a)uni-**konstanz.de <michael.seiferle(a)uni-konstanz.de>> > > wrote: > > > > Hi Pushkaraj, > >> > >> thanks in return for your response. > >> I will see if I can reproduce that in my VM; so far you are the first > one > >> to report this issue, I'll let you know what I can find. > >> > >> Kind regards > >> > >> Michael > >> > >> Am 19.01.2011 um 20:19 schrieb Pushkaraj Thorat: > >> > >> Thanks for your response Michael, > >>> > >>> I am using java 1.6 > >>> > >>> pushkaraj@toothless:~$ java -version > >>> java version "1.6.0_17" > >>> Java(TM) SE Runtime Environment (build 1.6.0_17-b04) > >>> Java HotSpot(TM) Server VM (build 14.3-b01, mixed mode) > >>> pushkaraj@toothless:~$ > >>> > >>> Just to update, the rest server ran successfully on my windows machine. > >>> Not sure what problem faced on the linux(ubuntu) machine. I will debug > once > >>> I get some time. > >>> > >>> Thanks, Pushkaraj > >>> > >>> > >>> On Tue, Jan 18, 2011 at 3:46 AM, Michael Seiferle > <michael.seiferle@uni- > >>> **konstanz.de <michael.seiferle(a)uni-konstanz.de>> wrote: > >>> Dear Pushkaraj, > >>> > >>> I am deeply sorry for you having to mess around with that erroneous > >>> startup scripts. > >>> We fixed them in both the ZIP & DMG distribution, feel free to download > >>> them again. > >>> > >>> >> java.lang.**IncompatibleClassChangeError > >>> We have been trying to reproduce this error - but to no avail. > >>> Your error message might have to do something with your Java Version; > >>> please make sure you are running the latest version. > >>> > >>> Hope this helps! In case it does not, feel free to ask for more. > >>> > >>> Kind regards > >>> > >>> Michael > >>> > >>> Am 17.01.2011 um 22:00 schrieb Pushkaraj Thorat: > >>> > >>> > I am doing setup for REST enabled basex database with procedure > >>> mentioned in http://docs.basex.org/wiki/**JAX-RX_API< > http://docs.basex.org/wiki/JAX-RX_API>URL. > >>> > > >>> > Configuring & starting server and running failed due to class not > >>> found, but later I've modified the ./basexrest script as: (Included > all the > >>> jars in lib folder) > >>> > > >>> > ######START > >>> > #!/bin/bash > >>> > # Path to this script > >>> > PWD=`dirname $0` > >>> > # Paths to distributed files or source directories > >>> > BASEX=$PWD/BaseX.jar > >>> > BASEXAPI=$PWD/../lib/basex-**api.jar > >>> > # Classpath > >>> > LIB=$PWD/../lib > >>> > LIB_CP="" > >>> > for JAR_FILE in $LIB/*.jar > >>> > do > >>> > LIB_CP="$LIB/$JAR_FILE:$LIB_**CP" > >>> > done > >>> > CP=$BASEX:$BASEXAPI:$LIB_CP > >>> > # Options for virtual machine > >>> > VM=-Xmx1g > >>> > # Run REST server > >>> > java -cp "$CP" $VM org.basex.api.jaxrx.**JaxRxServer "$@" > >>> > > >>> > ######END > >>> > > >>> > after this, server started successfully, hit the URL - > >>> http://localhost:8984/basex/**jax-rx< > http://localhost:8984/basex/jax-rx>I am getting following exception: > >>> > > >>> > java.lang.**IncompatibleClassChangeError: Class > >>> javax.ws.rs.core.Response$**Status does not implement the requested > >>> interface javax.ws.rs.core.Response$**StatusType > >>> > at > com.sun.jersey.spi.container.**ContainerResponse.getStatus(** > >>> ContainerResponse.java:548) > >>> > at com.sun.jersey.spi.container.**ContainerResponse$** > >>> CommittingOutputStream.**commitWrite(ContainerResponse.**java:156) > >>> > at com.sun.jersey.spi.container.**ContainerResponse$** > >>> CommittingOutputStream.write(**ContainerResponse.java:133) > >>> > at org.basex.io.BufferedOutput.**flush(BufferedOutput.java:50) > >>> > at org.basex.io.PrintOutput.**flush(PrintOutput.java:126) > >>> > at org.basex.data.XMLSerializer.**cls(XMLSerializer.java:206) > >>> > at org.basex.data.Serializer.**close(Serializer.java:219) > >>> > at org.basex.api.jaxrx.BXJaxRx$1.**code(BXJaxRx.java:96) > >>> > at org.basex.api.jaxrx.BXCode.**run(BXCode.java:53) > >>> > at org.basex.api.jaxrx.BXOutput.**write(BXOutput.java:53) > >>> > at com.sun.jersey.core.impl.**provider.entity.** > >>> StreamingOutputProvider.**writeTo(**StreamingOutputProvider.java:**71) > >>> > at com.sun.jersey.core.impl.**provider.entity.** > >>> StreamingOutputProvider.**writeTo(**StreamingOutputProvider.java:**57) > >>> > at com.sun.jersey.spi.container.**ContainerResponse.write(** > >>> ContainerResponse.java:299) > >>> > > >>> > >>> > >>> ______________________________**_________________ > > BaseX-Talk mailing list > > BaseX-Talk(a)mailman.uni-**konstanz.de <BaseX-Talk(a)mailman.uni-konstanz.de > > > > https://mailman.uni-konstanz.**de/mailman/listinfo/basex-talk< > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk> > > >

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Re: [basex-talk] ajax and http server - cross-domain, jsonp or proxy?
by Maud Ingarao 30 Nov '11

30 Nov '11

Hello everybody, I am very new at BaseX http server, and at jQuery, and at this mailing list too :) Concerning the error you got Colin : thrown error: [Exception... "Access to restricted URI denied" code: "1012"... I suddenly have the same problem though basex and my files have the same domain : http://hyperdonat.tge-adonis.fr/basex/basex.html (The basex server is here : http://basex.tge-adonis.fr/rest) I had other problems before this with my script, but not this one, and I don't know what I did that produced it... Maud On Fri, Oct 21, 2011 at 12:00 PM, < basex-talk-request(a)mailman.uni-konstanz.de> wrote: > Send BaseX-Talk mailing list submissions to > basex-talk(a)mailman.uni-konstanz.de > > To subscribe or unsubscribe via the World Wide Web, visit > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > or, via email, send a message with subject or body 'help' to > basex-talk-request(a)mailman.uni-konstanz.de > > You can reach the person managing the list at > basex-talk-owner(a)mailman.uni-konstanz.de > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of BaseX-Talk digest..." > > > Today's Topics: > > 1. Re: Performance of Basex 7.0 XQuery execution (Christian Gr?n) > 2. Re: Performance of Basex 7.0 XQuery execution (Jan Vl?insk? (CAD)) > 3. Clustering/replicating? (Pascal Heus) > 4. Re: ajax and http server - cross-domain, jsonp or proxy? > (colin mcenearney) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 20 Oct 2011 15:43:50 +0200 > From: Christian Gr?n <christian.gruen(a)gmail.com> > To: Constantine Hondros <Constantine.Hondros(a)tomtom.com> > Cc: "basex-talk(a)mailman.uni-konstanz.de" > <basex-talk(a)mailman.uni-konstanz.de> > Subject: Re: [basex-talk] Performance of Basex 7.0 XQuery execution > Message-ID: > <CAP94bnPYC2abLTiQJkBPt1_WquH6ix8OQeU6HnJtxCa+cp-5Vg(a)mail.gmail.com > > > Content-Type: text/plain; charset=ISO-8859-1 > > Hi Constantine, > > > The XPath I showed was just a simple example of using the > preceding-sibling axis. > > I guessed so already.. Thanks for persisting ;) > > > I guess what I am asking is ... while most XPath queries I run are quick > to resolve, anything using preceding::, preceding-sibling:: or following::, > following-sibling:: essentially runs too slowly to be workable - at least, > on my sample dataset with about 100K sibling children of the root element. > > > > So is this any sort of known issue? Should I be looking at any sort of > configuration options? Is there any way to profile the execution of the > Xpath? > > It's true that BaseX is mostly optimized for descendant and ancestor > operations. In particular, the preceding/preceding-sibling axes will > always be slower, as our storage does not contain backward pointers to > preceding nodes. I'm pretty sure, though, that there are ways to > either optimize relevant queries or the internal optimizer strategies, > but we'll probably have to spend some more time on analyzing the > relevant bottlenecks.. > > Feel free to ask for more, > Christian > > > ------------------------------ > > Message: 2 > Date: Thu, 20 Oct 2011 19:20:29 +0200 > From: Jan Vl?insk? (CAD) <jan.vlcinsky(a)cad-programs.com> > To: Christian Gr?n <christian.gruen(a)gmail.com> > Cc: "basex-talk(a)mailman.uni-konstanz.de" > <basex-talk(a)mailman.uni-konstanz.de> > Subject: Re: [basex-talk] Performance of Basex 7.0 XQuery execution > Message-ID: > <CAAq9E_fb5KymrtL=xosGsH=BuP4aWpgip0OWxDJUAHANqqO1Ng(a)mail.gmail.com > > > Content-Type: text/plain; charset="utf-8" > > Hi Constantine > Just my side note. > As far as I remember, I found this sort of performance discussion with most > the XQuery processors I have tested (Sedna, Zorba, Saxon, eXist...). Each > time related to sibling, preceding etc. and each time explaining, that > indices are not containing pointers for tracking this relationship. My > feeling is, this could lead to much bigger index file and slower > performance > when adding documents and indexing. > My conlcusion is - optimizing this sort of queries has its cost and mostly > it is better (and somehow possible) to avoid these constructions. > > With best regards > > Jan > > *Ing. Jan Vl?insk?* > CAD programy > Slune?nicov? 338/3, 734 01 Karvin? R?j, Czech Republic > tel: +420-597 602 024; mob: +420-608 979 040 > skype: janvlcinsky; GoogleTalk: jan.vlcinsky(a)gmail.com > http://cz.linkedin.com/in/vlcinsky > > > > On 20 October 2011 15:43, Christian Gr?n <christian.gruen(a)gmail.com> > wrote: > > > Hi Constantine, > > > > > The XPath I showed was just a simple example of using the > > preceding-sibling axis. > > > > I guessed so already.. Thanks for persisting ;) > > > > > I guess what I am asking is ... while most XPath queries I run are > quick > > to resolve, anything using preceding::, preceding-sibling:: or > following::, > > following-sibling:: essentially runs too slowly to be workable - at > least, > > on my sample dataset with about 100K sibling children of the root > element. > > > > > > So is this any sort of known issue? Should I be looking at any sort of > > configuration options? Is there any way to profile the execution of the > > Xpath? > > > > It's true that BaseX is mostly optimized for descendant and ancestor > > operations. In particular, the preceding/preceding-sibling axes will > > always be slower, as our storage does not contain backward pointers to > > preceding nodes. I'm pretty sure, though, that there are ways to > > either optimize relevant queries or the internal optimizer strategies, > > but we'll probably have to spend some more time on analyzing the > > relevant bottlenecks.. > > > > Feel free to ask for more, > > Christian > > _______________________________________________ > > BaseX-Talk mailing list > > BaseX-Talk(a)mailman.uni-konstanz.de > > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > > >

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