BaseX-Talk February 2016

basex-talk@mailman.uni-konstanz.de

28 participants
35 discussions

client:query freeze
by Strasser Pablo 01 Mar '16

01 Mar '16

Hi, Thanks for your great software. Using basex 8.4. I found the following strange behaviour in client:query call. Calling a repository function which use client:query to call another repository function freeze the basex server if done on the server. The only way to stop the server is with a kill -9. However using the standalone client it work normally. Trying to reproduce this problem I managed to get a similar problem using 2 repository test and test2. Where the first repo use a function of the second. Do you have some idea how to investigate this problem? Is it a bug? Code of test: module namespace m = 'http://strasser-family.ch/test'; declare variable $m:c := client:connect('localhost', 1984, 'admin', 'admin'); declare function m:test(){ client:query($m:c, "import module namespace m = 'http://strasser-family.ch/test2';m:test()") }; Code of test2: module namespace m = 'http://strasser-family.ch/test2'; declare function m:test() { <dummy/> }; usage code: import module namespace m = 'http://strasser-family.ch/test'; m:test() Have a nice evening. Pablo

2 5

About user names
by France Baril 29 Feb '16

29 Feb '16

Hi, I'm looking at the user module because I want to implement a login feature on one of my web application. More specifically, I'm looking at the restrictions: http://docs.basex.org/wiki/Valid_Names#Valid_Names For web applications, it is very usual for people to use an email as a username. The restriction on the period character is very annoying in that regard. I understand why it's a restriction on database names, but for user names it creates a limit on the ability for less frequent users to access the site. Most people remember which email they used or have only 2 or 3 to try. Passwords are saved in keychains. However, remembering a username... pfff! Is there any way that the restrictions on user names could be adapted to allow for characters that are valid for an email address in the near future? -- France Baril Architecte documentaire / Documentation architect france.baril(a)architextus.com

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Re: [basex-talk] basex-xqj source?
by Kendall Shaw 29 Feb '16

29 Feb '16

Oh, it’s here: http://xqj.net/basex/download.jsp Kendall From: <basex-talk-bounces(a)mailman.uni-konstanz.de<mailto:basex-talk-bounces@mailman.uni-konstanz.de>> on behalf of Kendall Shaw <kendall.shaw(a)workday.com<mailto:kendall.shaw@workday.com>> Date: Monday, February 22, 2016 at 3:27 PM To: "basex-talk(a)mailman.uni-konstanz.de<mailto:basex-talk@mailman.uni-konstanz.de>" <basex-talk(a)mailman.uni-konstanz.de<mailto:basex-talk@mailman.uni-konstanz.de>> Subject: [basex-talk] basex-xqj source? Hi, Where can I find source code for the basex xqj implementation? I want to see what it is doing. Thanks, Kendall

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Re: [basex-talk] Add docments and retrieve results using java
by Kendall Shaw 23 Feb '16

23 Feb '16

It looks like the basex-test projects shows how to do what I want. Using QueryProcessor and the Xdm classes. Kendall From: <basex-talk-bounces(a)mailman.uni-konstanz.de<mailto:basex-talk-bounces@mailman.uni-konstanz.de>> on behalf of Kendall Shaw <kendall.shaw(a)workday.com<mailto:kendall.shaw@workday.com>> Date: Monday, February 22, 2016 at 4:56 PM To: "basex-talk(a)mailman.uni-konstanz.de<mailto:basex-talk@mailman.uni-konstanz.de>" <basex-talk(a)mailman.uni-konstanz.de<mailto:basex-talk@mailman.uni-konstanz.de>> Subject: [basex-talk] Add docments and retrieve results using java How can I incrementally import XML documents into the database, using java? And, how can I incrementally retrieve query results and XML documents from the database, using java? Either I am missing it, or XQJ does not allow you to store data into a database. Should I use xmldb API? Or, should I use the native API? If so how do I incrementally read and write, instead of loading everything into a string or reading and writing to/from files? Kendall

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Add docments and retrieve results using java
by Kendall Shaw 22 Feb '16

22 Feb '16

How can I incrementally import XML documents into the database, using java? And, how can I incrementally retrieve query results and XML documents from the database, using java? Either I am missing it, or XQJ does not allow you to store data into a database. Should I use xmldb API? Or, should I use the native API? If so how do I incrementally read and write, instead of loading everything into a string or reading and writing to/from files? Kendall

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basex-xqj source?
by Kendall Shaw 22 Feb '16

22 Feb '16

Hi, Where can I find source code for the basex xqj implementation? I want to see what it is doing. Thanks, Kendall

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Benchmarking and caching in BaseX
by Bram Vanroy | KU Leuven 21 Feb '16

21 Feb '16

Dear all My name is Bram Vanroy, and I am an intern at the Centre for Computational Linguistics (CCL; http://www.arts.kuleuven.be/ling/ccl [Dutch]) at the University of Leuven. My supervisor, Vincent Vandeghinste, has had contact with this mailing list some time ago, more specifically with Dirk Kirsten. My intership is titled "Fine-tuning the GrETEL Treebank Query Engine". GrETEL stands for Greedy Extraction of Trees for Empirical Linguistics; available at http://gretel.ccl.kuleuven.be/gretel-2.0/. Its goal is to provide users with a fast, user-friendly on-line tool to search through text corpora backed by treebanks. Accessibility is an important point for us: users do not need to be proficient with any programming languages, strict formalisms, or treebank specific annotations; every query can be executed by using an intuitive graphical interface. More advanced users can use XPath to write the representation of the syntactic structure that they are looking for. BaseX is our tool of choice as a database for our corpora in XML format. Initially, GrETEL provided access to smaller corpora such as CGN (9 million words) and Lassy Small (1 million words). We would like to expand the searchable corpora by also making the full Sonar corpus available (500 million words). This is already partially possible in GrETEL 2.0 but due to efficiency reasons, capabilities are restricted: users can only search in one component at a time, and the largest component in the corpus is not available due to its size (15 million sentences). We have applied these restrictions because the search time for the whole corpus was too long, which in turn would decrease the user-friendliness of the tool drastically. Steps have already been taken to improve search times in larger corpora. (See "Making a Large Treebank Searchable Online. The SoNaR Case." by Vincent Vandeghinste, and Liesbeth Augustinus; http://nederbooms.ccl.kuleuven.be/documentation/LREC2014-GrETELSoNaR.pdf.) To spare you the effort to go through the whole article, I hereby quote the most relevant citation from that article for this email: The general idea behind our approach is to restrict the search space by splitting up the data in many small databases, allowing for faster retrieval of syntactic structures. We organise the data in databases that contain all bottom-up subtrees for which the two top levels (i.e. the root and its children) adhere to the same syntactic pattern. When querying the database for certain syntactic constructions, we know on which databases we have to apply the XPath query which would otherwise have to be applied on the whole data set. We have called this method GrETEL Indexing (GrInd). (p. 17) So to optimise searching, the data has been pulled apart - in a sense - which would make the search space smaller and subsequently the search time shorter. In the future we would like to apply this technique on parallel corpora as well. We have not tested yet what influence this change has made to query time which is what I am going to find out during my internship. I have already analysed the XPath queries that users have made since GrETEL saw its first user and found that the queries are ten embedded levels deep at the most, but most are between one and five. The amount of nodes per query varies between one and 24, but most searches are for structures that contain between one and eight nodes. Based on this information, I am writing example XPaths that I am going to pull through BaseX as a sort of benchmark. I can then compare the query speeds between the split-up corpus, and the regular one. The problem that I have encountered is that BaseX seems to cache very efficiently. Obviously this is not a problem on production websites but for benchmarking it may not be ideal. My first question to you, then, is: is it possible to disable caching when testing queries locally? And how exactly does BaseX handle the caching? Or more specifically, if I enter a query: what is cached, and for how long? This information me be useful to analyse our logs with. If you have any feedback on GrETEL, or the new approach of GrInding, or if you have any ideas to improve search time for large corpora - I would love to hear from you, you can contact me via this email address or on LinkedIn. I reply to each email as extensively as possible. Thank you in advance, Kind regards Bram Vanroy https://be.linkedin.com/in/bramvanroy

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from xquery:parse to data paths ...
by Hans-Juergen Rennau 20 Feb '16

20 Feb '16

Dear BaseX team, perhaps I hear an opinion about the following idea. (1) The function xquery:parse is already immensely useful as it allows to *validate* XPath expressions, as for example used in configuration data. (A practical example: the XPath expressions used in JMeter [1] test plans in order to extract message data and define test assertions.) (2) Given the XSDs of a Web Service (or other application), it is possible to determine all valid data paths (e.g. /a/b/c is valid, /a/b/C is not valid). (3) If there were a reliable way to map the output of xquery:parse to the implied data paths, then one could use xquery:parse to validate xpath expression not only for syntactic correctness (which is already very much!), but also for consistency with application XSDs. This would be extremly usefuly as XSDs evolve and a checking if configuration-based XPath expressions must be adapted is otherwise very difficult to achieve in any systematic way. (4) Looking at the xquery:parse output, it seems certainly feasible to write such a mapping (xquery:parse output => data paths); but the problem I see is that the format is not guaranteed to be stable, as it is no standard. (And it is probably not described.) If BaseX provided such a functionality as an additional extension function (e.g. xquery:data-paths($query as xs:string)) you would simply be - heros. Cheers,Hans-Jürgen [1] http://jmeter.apache.org/ PS: Illustrative example. let $query := "/descendant::OutboundFlight[Status = 'Booked'][1]/FlightDeparture/DepartureTime"return xquery:parse($query)=><MainModule updating="false"> <QueryPlan compiled="false"> <CachedPath> <Root/> <IterPosStep axis="descendant" test="OutboundFlight"> <CmpG op="="> <CachedPath> <IterStep axis="child" test="Status"/> </CachedPath> <Str value="Booked" type="xs:string"/> </CmpG> <Int value="1" type="xs:integer"/> </IterPosStep> <IterStep axis="child" test="FlightDeparture"/> <IterStep axis="child" test="DepartureTime"/> </CachedPath> </QueryPlan> </MainModule> let $query := "/descendant::OutboundFlight[FlightDeparture/DepartureDate][1]/FlightDeparture/DepartureDate"return xquery:data-paths($query)=>//OutboundFlight/FlightDeparture/DepartureTime,//OutboundFlight/Status

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Header problems and xmlns
by Ana Victória Ladeira 20 Feb '16

20 Feb '16

Good afternoon! I currently have a dataset with some files that use the following header (I will call it Header1): <?xml version="1.0" encoding="ISO-8859-1"?><CURRICULO-VITAE SISTEMA-ORIGEM-XML="LATTES_OFFLINE" xmlns:lattes=" http://www.cnpq.br/2001/XSL/Lattes" NUMERO-IDENTIFICADOR="X" DATA-ATUALIZACAO="07122015" HORA-ATUALIZACAO="010008" xsi:schemaLocation=" http://www.cnpq.br/2014/XSD/Lattes/Versao1 CurriculoLattes.xsd" xmlns=" http://www.cnpq.br/2014/XSD/Lattes/Versao1" xmlns:xsi=" http://www.w3.org/2001/XMLSchema-instance"> Other files use this other header (Header2): <?xml version="1.0" encoding="UTF-8"?><CURRICULO-VITAE SISTEMA-ORIGEM-XML="LATTES_OFFLINE" DATA-ATUALIZACAO="13072015" HORA-ATUALIZACAO="145233" NUMERO-IDENTIFICADOR="X" xmlns:lattes=" http://www.cnpq.br/2001/XSL/Lattes"> Using the same query, I can extract data from files with Header2, but now with Header1. I'm only using FLWOR expressions, and the queries are very simple. I've tried with multiple queries, and the result is always the same: I'm able to extract the information I want from files with Header2, but not from the ones with Header1. I think its a problem with the namespace, but I don't know how to solve it. Can anyone please help me with that? Thank you in advance, Ana Victória Ladeira

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Odd Behavior from Ruby Client
by Eliot Kimber 20 Feb '16

20 Feb '16

I have my Ruby-based server-side commit hooks working but now I'm seeing a failure result I can't figure out yet. I have a large sample data set that I'm using for testing (https://hub.docker.com/r/ditacommunity/demo-content/). This content is non-trivial DITA and all the files are valid (e.g., Oxygen validates the maps and topics). However, when I load the files via my Ruby script that uses the BaseXClient.rb file, a few of the files fail to load with the error indicating that something in the BaseX client/server chain is trying to interpret the XML data as a file path. As far as I can tell it's the same documents every time, so I suspect there is something about the documents' details that is causing this. I guess my question is: what could cause this behavior and how might I go about debugging and correcting it? The Ruby script is here: https://github.com/dita-for-small-teams/dfst-git-commit-hooks/blob/develop/ server-side/post-receive I probably have to rewrite the script to use the REST API so that I have more control over the encoding details (per earlier discussion of how to handle UTF-16 documents) but I'd still like to what's causing this as it points up to either a really subtle user error or a flaw in the basic API mechanism. Cheers, Eliot ---- Eliot Kimber, Owner Contrext, LLC http://contrext.com

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BaseX-Talk February 2016