BaseX-Talk March 2015

basex-talk@mailman.uni-konstanz.de

36 participants
58 discussions

BaseX 8.1: The Spring Edition
by Christian Grün 28 Mar '15

28 Mar '15

Dear all, Our traditional spring edition has just been released! We are delighted to present BaseX 8.1, our XML database and XQuery 3.1 processor, which gives you the following new features: XQUERY - efficient Finger Tree algorithm for arrays - prof:variables() outputs list of currently bound variables - new higher-order functions: hof:scan-left, hof:take-while WEB APPLICATIONS - the Web Module offers convenience functions for building web apps - RESTXQ: %input annotation; input-specific content-type parameters OPTIONS - RESTPATH: specify server path for queries and command scripts - IGNORECERT: ignore untrusted certificates when connecting to servers COMMAND-LINE - Bind input strings to the query context with -I You find the new release at http://basex.org. We are looking forward to your feedback, Christian BaseX Team

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Performance related query.
by ankit kumar 27 Mar '15

27 Mar '15

Hi, I am getting performance issue while using my own xquery library. I have written an xquery module which contains a single function which return all the categories belong to a set of products as given below. Also there is one constrain that i cannot pass all the category to the getCategory() function as argument. I have to take only products as input. I tried to take /products/p:category directly instead of $lib:category variable. but it is showing root not found. So i have to defined it as global variable. =====XQUERY MODULE====product_library.xq module namespace lib = "product_library"; declare namespace p="a:b:c"; declare variable $lib:category := /products/p:category; declare function lib:getCategory($products){ let $catRefs := distinct-values($products/@catid) return $lib:category[@id = $catRefs] }; Then i am including this library in another file, where i am invoking getCategory() function of the module. My code for that is given below. ======Client Code ====== product_client.xq import module 'product_library' at 'file:///C:/Users/ankumar/Desktop/product_library.xq'; declare namespace lib ="product_library"; declare namespace p="a:b:c"; let $products := /products/*[@catid] return count(lib:getCategory($products)) Executing the above code is taking too long. So, I stopped that and write the same logic of getCategory() function of module in the same Client file as given below. =====Changed Client Code========== import module 'product_library' at 'file:///C:/Users/ankumar/Desktop/product_library.xq'; declare namespace lib ="product_library"; declare namespace p="a:b:c"; let $products := /products/*[@catid] (: return count(lib:getCategory($products)) :) let $catRefs := distinct-values($products/@catid) return count(/products/p:category[@id = $catRefs]) It is executing very fast, and giving me the desired result with a second. I don't know why it is happening. My whole module is written in that way only. If you have any idea, why it is happening and how can i make this efficient then share with me. I am attaching my module file, client file,the xml instance file and the query info for with module and without module file with the mail. Is there anything to do with query optimization ?. large.xml <https://docs.google.com/file/d/0B_pB7l14skhVMkxzVjZpRWJ3blU/edit?usp=drive_…>

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memory usage when writing files
by Lars Johnsen 27 Mar '15

27 Mar '15

Hi all Here is code that gradually eats up memory, whether run in GUI or as command. All it does is creating temporary collections out of folders, and writing them to file. Is there a simple way to avoid this code to eat up memory? It runs out of memory (set at 12GB for command, 18GB in GUI) after 300 folders or so, and it has to process 20 000 of them. Best Lars G Johnsen Norwegian National Library Here is the actual code (: process list of folders :) for $collections in file:list($digibooks) let $html := $htmlfiles || substring-before($collections, "_ocr") || ".html" return (: code is rerun so check if files exist :) if (not(file:exists($html))) then try { (: create a temporary collection of the files and write result to disk :) file:write( $html, db:digibok-to-html( collection($digibooks || $collections)) ) } catch * { $err:code } else ()

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DITA for Small Teams Git-to-BaseX Hooks
by Eliot Kimber 26 Mar '15

26 Mar '15

I think I have my git hooks for loading XML into BaseX working well enough (there's more refinement to do but the minimum functionality is there). The code is available here: https://github.com/dita-for-small-teams/dfst-git-commit-hooks/tree/develop (That's on the develop branch) The functionality works as follows: - On checkout of a branch, see if a corresponding database is in BaseX, if not, create the database (named for the repo directory and branch), load all XML files (*.xml,*.dita,*.ditamap), and capture the git branch name and commit hash. If the database exists and the commit is not the current commit, reflect changes from the DB's commit and the branch's commit. - On commit or merge, update the database to reflect the changes between HEAD and HEAD^ I do not react (yet) to branch delete, but BaseX database maintenance is easy enough that it would be hard (e.g., just drop the database for that branch). I think this set hooks is sufficient to ensure that the BaseX databases will always be in sync with the git repo. I'm using the approach of one database per branch so that I can then implement branch-aware queries in the repo. This is essential for link management where you want to be able to view the documents through specific branch such that non-version-specific links will resolve to the version visible on that branch (this approach doesn't handle being able to resolve to older versions--that would require maintaining per-commit databases, although that might be necessary for certain use cases, hmmm). Thanks for all the help here, especially Charles Duffy's help with bash script coding. Cheers, E. ————— Eliot Kimber, Owner Contrext, LLC http://contrext.com

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Failure on Second Update to Database
by Eliot Kimber 26 Mar '15

26 Mar '15

I'm getting a failure on the second commit of XML data via the basexclient command (from my git hook code). I've created a gist here: https://gist.github.com/dc9f6d55d891b06ecae9.git with relevant logs and the data/ directory. The exception reported is: ================== Contrext01:dfst-sample-project ekimber$ git add .;git commit -m "updated test file" Running: basexclient -c CHECK\ dfst_master\;\ OPEN\ dfst_master\;\ REPLACE\ docs/topic-01.dita\ /Users/ekimber/workspace-dfst/dfst-sample-project/docs/topic-01.dita -U admin -P admin -p 1984 -n localhost Running: basexclient -c CHECK\ dfst_master\;\ OPEN\ dfst_master\;\ REPLACE\ dfst/metadata.xml\ \<dfst_metadata\>\<gitstate\>\<branch\>master\</branch\>\<commit\>8d264e1e7 3d5596758a069a4355920c448a5b41d\</commit\>\</gitstate\>\</dfst_metadata\> -U admin -P admin -p 1984 -n localhost Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk(a)mailman.uni-konstanz.de Version: BaseX 8.0.3 Java: Oracle Corporation, 1.7.0_65 OS: Mac OS X, x86_64 Stack Trace: java.lang.RuntimeException: Data Access out of bounds: - pre value: 21 - #used blocks: 1 - #total locks: 1 - access: 0 (1 > 0] at org.basex.util.Util.notExpected(Util.java:60) at org.basex.io.random.TableDiskAccess.cursor(TableDiskAccess.java:462) at org.basex.io.random.TableDiskAccess.read1(TableDiskAccess.java:148) at org.basex.data.Data.kind(Data.java:304) at org.basex.data.atomic.Replace.getInstance(Replace.java:42) at org.basex.data.atomic.AtomicUpdateCache.addReplace(AtomicUpdateCache.java:9 5) at org.basex.core.cmd.Replace.replace(Replace.java:95) at org.basex.core.cmd.Replace.run(Replace.java:57) at org.basex.core.Command.run(Command.java:379) at org.basex.core.Command.execute(Command.java:95) at org.basex.server.ClientListener.run(ClientListener.java:146) [master 8d264e1] updated test file 1 file changed, 1 insertion(+), 1 deletion(-) Contrext01:dfst-sample-project ekimber$ ================= The first update succeeds, the second one fails. The second one is committing literal XML on the command while the first is committing a file on the file system. This behavior is consistent: if I drop the database, restart the server, the repeat this test, I get the same failure. Is this my user error or a bug? Cheers, E. ————— Eliot Kimber, Owner Contrext, LLC http://contrext.com

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Configuration File for Basexclient Connection Details?
by Eliot Kimber 25 Mar '15

25 Mar '15

Looking through the docs and trying to tests locally, it appears that the basexclient command does not use the USER or PASSWORD fields in .basex when run. That is, given this in my ~/.basex file: USER = admin PASSWORD = admin The basexclient command still prompts me for my credentials. Is this correct or am I missing a configuration option somewhere? What I'm looking for is the ability to call the basexclient command from git hooks without those scripts having to maintain their own configuration file for the connection details. Thanks, Eliot ————— Eliot Kimber, Owner Contrext, LLC http://contrext.com

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Re: [basex-talk] Simple xQuery functions do not work as expected
by Goetz Heller 25 Mar '15

25 Mar '15

Hi Christian, the issue showed up again, this time outside of a function. The computer was only moderately charged, but the change of behavior occurred after I loaded a 25MB text file into Notepad++. Should I change something in the JVM settings? Kind regards, Goetz -----Ursprüngliche Nachricht----- Von: Christian Grün [mailto:christian.gruen@gmail.com] Gesendet: Mittwoch, 25. März 2015 11:27 An: Goetz Heller Betreff: Re: [basex-talk] Simple xQuery functions do not work as expected > P.S.: Please make sure that our conversation appears at BaseX-Talk since I'm receiving mails from other members of the community who do appear to not be informed about the current status. I continued to write directly to you, because your second e-mail was not directed to the list anymore. It makes perfectly sense to include the list as well. > > > -----Ursprüngliche Nachricht----- > Von: Christian Grün [mailto:christian.gruen@gmail.com] > Gesendet: Mittwoch, 25. März 2015 09:38 > An: Goetz Heller > Betreff: Re: [basex-talk] Simple xQuery functions do not work as > expected > >> However, I would not consider this issue as resolved. > > Obviously yes. > >> For me it is a hint that under heavy load (memory), such misbehavior might occur, and therefore some investigations make sense in my opinion. > > I was surprised to hear that a restart of your machine solved the problem, because the GUI is nothing else than a plain JVM instance with a low memory footprint (at least for queries like the one you sent to me). > > As I cannot remember to have encountered a similar problem, we rely on your feedback. Feel free to send us some more examples if the problem should decide to haunt you. > > Best, > Christian > > >> >> Kind regards, >> >> Goetz >> >> -----Ursprüngliche Nachricht----- >> Von: Christian Grün [mailto:christian.gruen@gmail.com] >> Gesendet: Dienstag, 24. März 2015 17:12 >> An: Goetz Heller >> Betreff: Re: [basex-talk] Simple xQuery functions do not work as >> expected >> >> I am using Windows as well. >> >> Does the problem also happen with the latest snapshot? Could you try the zip distribution? >> >> http://files.basex.org/releases/latest/ >> >> >> >> On Tue, Mar 24, 2015 at 5:07 PM, Goetz Heller <heller(a)hellerim.de> wrote: >>> Did you try it on the Windows platform already? Maybe there was a mistake when packaging. >>> >>> Kind regards, >>> >>> Goetz >>> >>> -----Ursprüngliche Nachricht----- >>> Von: Christian Grün [mailto:christian.gruen@gmail.com] >>> Gesendet: Dienstag, 24. März 2015 16:50 >>> An: Goetz Heller >>> Betreff: Re: [basex-talk] Simple xQuery functions do not work as >>> expected >>> >>> Strange. Do you possibly have an empty or out-dated database named "labels"? If yes, could you try to back up and delete it, and run the query again? >>> >>> >>> On Tue, Mar 24, 2015 at 4:45 PM, Goetz Heller <heller(a)hellerim.de> wrote: >>>> Hi Christian, >>>> >>>> here ist he complete output. Apparently, it's over-optimized: >>>> >>>> Result: >>>> >>>> <r>et | </r> >>>> >>>> >>>> Compiling: >>>> - pre-evaluating doc("C:\test\labels.xml") >>>> - applying attribute index for $key_0 >>>> - applying attribute index for "_and" >>>> - inlining local:getLabel#2 >>>> - removing redundant $key_4 as xs:string* cast. >>>> - removing redundant $lang_5 as xs:string* cast. >>>> - inlining $key_4 >>>> - inlining $lang_5 >>>> - removing unknown element/attribute TERM >>>> - pre-evaluating db:attribute("Labels", >>>> "_and")/self::*:label/parent::*:LABEL/()/text() >>>> - pre-evaluating ((: xs:string*, true :) ()) >>>> - simplifying flwor expression >>>> - inlining $retVal1_2 >>>> - inlining $retVal2_3 >>>> - simplifying flwor expression >>>> >>>> >>>> >>>> Query: >>>> declare variable $labels := doc('C:\test\labels.xml'); declare >>>> function local:getLabel( $key as xs:string*, $lang as xs:string* ) >>>> as >>>> xs:string* { $labels/LABELS/LABEL[@label = $key]/TERM[@LG = >>>> $lang]/text() }; let $retVal1 := $labels/LABELS/LABEL[@label = >>>> '_and']/TERM[@LG = 'FR']/text() let $retVal2 := >>>> local:getLabel('_and', >>>> 'FR') return <r>{$retVal1} | {$retVal2}</r> >>>> >>>> >>>> >>>> Optimized Query: >>>> element r { (db:attribute("Labels", >>>> "_and")/self::*:label/parent::*:LABEL/*:TERM[(@*:LG = "FR")]/text(), " >>>> | ", ()) } >>>> >>>> >>>> Result: >>>> - Hit(s): 1 Item >>>> - Updated: 0 Items >>>> - Printed: 12 Bytes >>>> - Read Locking: global >>>> - Write Locking: none >>>> >>>> >>>> Timing: >>>> - Parsing: 1.32 ms >>>> - Compiling: 154.5 ms >>>> - Evaluating: 0.43 ms >>>> - Printing: 0.01 ms >>>> - Total Time: 156.26 ms >>>> >>>> >>>> Query plan: >>>> <QueryPlan compiled="true"> >>>> <CElem> >>>> <QNm value="r" type="xs:QName"/> >>>> <IterPath> >>>> <ValueAccess data="Labels" type="ATTRIBUTE"> >>>> <Str value="_and" type="xs:string"/> >>>> </ValueAccess> >>>> <IterStep axis="self" test="*:label"/> >>>> <IterStep axis="parent" test="*:LABEL"/> >>>> <IterStep axis="child" test="*:TERM"> >>>> <CmpG op="="> >>>> <CachedPath> >>>> <IterStep axis="attribute" test="*:LG"/> >>>> </CachedPath> >>>> <Str value="FR" type="xs:string"/> >>>> </CmpG> >>>> </IterStep> >>>> <IterStep axis="child" test="text()"/> >>>> </IterPath> >>>> <Str value=" | " type="xs:string"/> >>>> <Empty size="0"/> >>>> </CElem> >>>> </QueryPlan> >>>> >>>> Kind regards, >>>> >>>> Goetz >>>> >>> >> >

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Facing Problem With Max()
by ankit kumar 25 Mar '15

25 Mar '15

Hi, I am trying to get max value for a sequence of nodes using max(). I have a query which gives me a set of element and after that i get its max value. let $elements := (<date>10-02-2012</date>,<date>12-02-2012<date>); return max($element) I am expecting that it gives me 10-02-2012, while it is giving error "cannot cast to double '10-02-2012'. Thanks Ankit

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Simple xQuery functions do not work as expected
by Goetz Heller 25 Mar '15

25 Mar '15

I tried to implement a simple Xml-based dictionary. Here is a fragment of the Xml data I’m using: <?xml version="1.0" encoding="utf-8"?> <LABELS> <LABEL label="_and"> <TERM LG="EN">and</TERM> <TERM LG="FR">et</TERM> <TERM LG="DE">und</TERM> <TERM LG="BG">и</TERM> <TERM LG="CS">a</TERM> <TERM LG="DA">og</TERM> <TERM LG="EL">και</TERM> <TERM LG="ES">y</TERM> <TERM LG="ET">ja</TERM> <TERM LG="FI">ja</TERM> <TERM LG="HU">és</TERM> <TERM LG="IT">e</TERM> <TERM LG="LT">ir</TERM> <TERM LG="LV">līdz</TERM> <TERM LG="MT">u</TERM> <TERM LG="NL">en</TERM> <TERM LG="PL">i</TERM> <TERM LG="PT">e</TERM> <TERM LG="RO">şi</TERM> <TERM LG="SK">a</TERM> <TERM LG="SL">in</TERM> <TERM LG="SV">och</TERM> </LABEL> </LABELS> Say it’s saved on C:\test\labels.xml. Now, I defined the following module: BEGIN_CODE>>> (:: default language:) declare variable $lang as xs:string := 'DE'; (:: dictionary :) declare variable $labels := doc('C:\test\Labels.xml'); (:: get localized label (default language) :) declare function local:getLabel( $key as xs:string* ) as xs:string* { $labels/LABELS/LABEL[compare(@label, $key) = 0]/TERM[compare(@LG, $lang) = 0]/text() }; (:: get localized label (specific language) :) declare function local:getLabel( $key as xs:string*, $lang as xs:string* ) as xs:string* { $labels/LABELS/LABEL[compare(@label, $key) = 0]/TERM[compare(@LG, $lang) = 0]/text() }; (:: get localized label (specific language) - debug version :) declare function local:getLabelDebug( $key as xs:string*, $lang as xs:string* ) { let $terms := $labels/LABELS/LABEL[compare(@label, $key) = 0]/TERM for $t in ($terms) return <t>{xs:string($t/@LG)}: {$t/text()} (comparison: {$t/@LG = $lang})</t> }; (: does not work as I expect: let $retVal := local:getLabel('_and', 'FR') because it returns nothing :) (: using "for $t in ($terms[compare(@LG, $lang) = 0])" yields empty result :) let $retVal := local:getLabelDebug('_and', 'FR') return <r>{$retVal}</r> <<<END_CODE The first function appears to work as expected. However, instead of “[@LG = $lang]” I had to use [compare(@LG, $lang) = 0]” – I don’t know why, but otherwise, it does not return any results. On the other hand, using “[@label = $key]” on the same line worked. The second function does not return anything at all. The debug version of the latter shows that all the needed information is in place. Obviously, usage of the same variable name globally and locally is not an issue (I’ve tried it out). What’s wrong with the code? Is there an issue with the current version (8.0.3)? My installation runs on a Windows 8.1 machine. Some help is appreciated. Kind regards, Goetz

3 2

GUI suggestion: no trace output when running tests
by Marc van Grootel 24 Mar '15

24 Mar '15

Hi, When running tests from the GUI I sometimes insert debugging code to figure out which tests fails or why. The current behavior of the GUI makes this impossible though because when tests are run this info is printed to the Query Info window but immediately after tests are run it prints the test summary overwriting the debugging info (such as trace output). Currently I then go to the command-line but it might be an idea to somehow keep the output generated during test run visible. Cheers, --Marc

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BaseX-Talk March 2015