May 2013 - BaseX-Talk - mailman.uni-konstanz.de

using data() is slow!
by James Wright 22 May '13

22 May '13

Hey Again, Sorry if I am here often. I got my system up and running and at first was seeing 1 second query times which is unacceptable. I started doing some research and trying different things. Here are some interesting things I found: 1) Using data() is SLOW!!! For example: (//DataElement(data(Name) = 'Transformer'])[1] : this takes 350 ms avg to complete (Most of it evaluation)(//DataElement(Name = 'Transformer')[1] : this takes 4 - 10 ms. Not sure why this is, but its good to know. I'm assuming the data() usage circumvents the indexes or something... 2) In a dynamic context is often worthwhile to 'construct' a query with the names embedded and execute xquery:eval rather than using variables within the expression. For example when trying to find a node based on a key property name which you don't know until run time: ($page:database//DataElement[(*|@*)[name() = $keyPropName)] = $entityId])[1] Above query takes about 1200 ms to complete in our data. If you have more than one of these being executed, it jumps to 10,000 ms or more!! xquery:eval("($context//" || $entityListName || "[" || $keyPropertyName || " = $entityId])[1]", map{ '$context' := $page:database, '$entityId' := $entityId }) This query takes between 2 - 8 ms to complete. Awesome!! Just thought I would share my findings! So far I am really enjoying BaseX!! Thanks for all the hard work! - James

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Support for "Feature 'http://apache.org/xml/features/xinclude' is not recognized."
by subbarao＠intense.in 22 May '13

22 May '13

Dear BaseX, I am getting following exception while creating XML DB org.basex.core.BaseXException: "file://XML/Backup/149874654.XML": Feature 'http://apache.org/xml/features/xinclude' is not recognized. at org.basex.core.Command.execute(Command.java:73) at org.basex.core.Command.execute(Command.java:85) at core.data.CRSXqueryComp.addXML(CRSXqueryComp.java:123) And following are the Jars files using in my project BaseX671.jar basex-api.jar xmldb-api-1.0.jar xom-1.2.1.jar xwork-2.0.4.jar xalan.jar xalan-2.7.0.jar xercesImpl-2.9.1.jar xml.jar xml-apis.jar Please suggest me the way forward. Thanks & Regards Subbu

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Quick question regarding subsequences
by James Wright 22 May '13

22 May '13

Hey, In the BaseX implementation this query: ($context//*[name() = $type and data((*|@*)[name() = $entityMetadata/property[@key = 'true']/@name]) = $entityId])[1] Will the query execute completely and then a 'subset' of 1 will be extracted, or will it only execute until it find the '1st' item that matches the query? Maybe this is a general XQuery question but I figured it was implementation specific. - James

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Search based on count of particular word
by John Best 21 May '13

21 May '13

Hi there Below is a sample XML file. ******************************* <Docs> <Doc> <Name>Doc 1</Name> <Info>Hurray</Info> </Doc> <Doc> <Name>Doc 2</Name> <Info>Brinjal is king of vegetables.</Info> </Doc> <Doc> <Name>Doc 3</Name> <Info>Alexandar was a great king. His desire was to conquer the world and rule the world as a king.</Info> </Doc> <Doc> <Name>Doc 4</Name> <Info>I love cherries.</Info> </Doc> <Doc> <Name>Doc 5</Name> <Info>Mango is king of fruits. Alphonso is king of mangoes. So Alphonso is king's king.</Info> </Doc> </Docs> ************************ I want to search the <Info> tag for the word "king" and return the <Name> as output. I know this is simple... :) But the *order of the <Name> should be in order of the word searched (here it will be king) ie the most numbers will come first. * *Doc 5 (3 times king) * *Doc 3 (2 times king) * *Doc 2 (1 time king) * * * -- Have a nice day JBest

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[FULL TEXT] Indexing text in several languages
by Vincent 21 May '13

21 May '13

Dear BaseX Team, I have some text in different languages stored in my XML files (tagged with xml:lang attributes) and I'd like to perform efficient full text queries on it (using stemming, stopwords...). I planned to use full text index. I can't figure out how I can set full text index for different languages in a given database. Is there a way to do it ? Thanks, Vincent

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Re: [basex-talk] BaseX generate-id()
by Christian Grün 20 May '13

20 May '13

I’m not quite sure on what you were asking, but I noticed that the explanation of PRE and ID values in our Wiki was somewhat deficient. Please don‘t hesitate to have yet another look at the revised articles [1,2], which are hopefully more self-explanatory. If not, you are always invited to read the dissertation in more detail ;) [1] http://docs.basex.org/wiki/Database_Module#db:open-pre [2] http://docs.basex.org/wiki/Node_Storage _______________________________ On Mon, May 20, 2013 at 10:46 PM, James Wright <james.jw(a)hotmail.com> wrote: > How did I not notice this!! I have read through those modules so many times > now!! I think this is exactly what I was looking for. I expected there to be > some sort of persistent id because I skimmed the initial dissertation on > BaseX from several years ago and it talks about a persistent ID. In regards > to the 'pre' this ID represents the id of a node which 'hasn't' been > inserted yet but it does not necessarily denote the ID the node will take > when actually inserted... So whats the point? Is this more for internal > uses? Maybe I don't fully understand... > > Thanks for the quick reply! > > - James > >> From: christian.gruen(a)gmail.com >> Date: Mon, 20 May 2013 22:30:08 +0200 >> Subject: Re: [basex-talk] BaseX generate-id() >> To: james.jw(a)hotmail.com >> CC: basex-talk(a)mailman.uni-konstanz.de > >> >> Hi James, >> >> a node id generated via generate-id() is unique and the same during >> the runtime of a query. If you want to ensure that you are requesting >> the same nodes of a database, I recommend you to check out the >> node-id() and node-pre() functions of our database module [1]. >> >> Hope this helps, >> Christian >> >> [1] http://docs.basex.org/wiki/Database_Module >> ___________________________ >> >> On Mon, May 20, 2013 at 10:09 PM, James Wright <james.jw(a)hotmail.com> >> wrote: >> > In the W3C specs it says this method should generate the same ID for a >> > node >> > regardless of when its called. Is this how it is implemented in BaseX or >> > does it simply generate a random number? My testing seems to implicate >> > the >> > ladder. If it does generate the same ID for each node each time its run, >> > does it do ensure uniqueness at the db or resource level? >> > >> > Thx for your time. >> > - James >> > >> > _______________________________________________ >> > BaseX-Talk mailing list >> > BaseX-Talk(a)mailman.uni-konstanz.de >> > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk >> >

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Redo logs. Feature
by Alexander Shpack 20 May '13

20 May '13

Hi Team! Oracle DB have very powerful feature for recovery operations http://docs.oracle.com/cd/B28359_01/server.111/b28310/onlineredo001.htm Is it possible to realize something similar?

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BaseX generate-id()
by James Wright 20 May '13

20 May '13

In the W3C specs it says this method should generate the same ID for a node regardless of when its called. Is this how it is implemented in BaseX or does it simply generate a random number? My testing seems to implicate the ladder. If it does generate the same ID for each node each time its run, does it do ensure uniqueness at the db or resource level? Thx for your time.- James

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XQuery question
by Marco Lettere 20 May '13

20 May '13

Hello all, sorry this email is not properly basex specific but rather XQuery related. What is the most correct, most efficient in general best way of treating sequences sequentially? In particular I have an XML describing a sequence of set operations that have to be applied sequentially to the contained sequences of <tem/>s resulting into a final set represented by a sequence of <item/>s. Unfortunately they are expressed as siblings (flat) rather than dependent nodes (nested hierarchy) which could be handled easily with recursion. As an example the following sequence shall add the first three items to the empty set then cut down the resulting set to only contain item 2 and 3 and finally remove item 2 from the set resulting in a final set containing only item 3. <set operator="UNION"> <item name="1"/> <item name="2"/> <item name="3"/> </set> <set operator="INTERSECT"> <item name="2"/> <item name="3"/> <item name="4"/> <item name="5"/> </set> <set operator="DIFFERENCE"> <item name="2"/> </set> I'd prefer to not have to alter the input data structure. Thanks a lot for any help, M.

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Re: [basex-talk] BaseX-Talk Digest, Vol 41, Issue 28
by Francis Avila 20 May '13

20 May '13

Gosh, I've been up and down the commands list looking for this. I can't believe I missed it! Thanks! On May 19, 2013, at 5:00 AM, basex-talk-request(a)mailman.uni-konstanz.de wrote: > From: Dirk Kirsten <dk(a)basex.org> > Subject: Re: [basex-talk] Easy way to serialize a DB to files? > Date: May 18, 2013 4:09:15 PM CDT > To: basex-talk(a)mailman.uni-konstanz.de > > > Dear Francis, > > There is the Export command, which should do exactly what you want. Read more about it here: http://docs.basex.org/wiki/Commands#EXPORT > > Cheers, > Dirk -- Francis Avila Web Developer Dancing Mammoth, Inc. (Formerly PJ Doland Web Design, Inc.) E: favila(a)dancingmammoth.com http://dancingmammoth.com

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