BaseX-Talk April 2012

basex-talk@mailman.uni-konstanz.de

38 participants
48 discussions

Database opened by another process while using REST interface
by Seenivasan Gunabalan 11 Apr '12

11 Apr '12

Hi All, I am getting "[BASX0020] Database 'db' is opened by another process." whenever I am trying to PUT / Store new record in to the database using the REST. I havn't kept the database open from anyother client. May I know what is the issue here? Thanks.

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Javadoc for XML:DB BaseX implementation
by Isidre Guixà 11 Apr '12

11 Apr '12

Hi Where can I found the Javadoc for XML:DB BaseX implementation? I see BaseX - XML:DB provides services that are not defined in official XML: DB and I would like to have the documentation. Thanks! Isidre Guixà

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fn:collection
by Róbert Kohányi 09 Apr '12

09 Apr '12

BaseX's documentation and the following (an excerpt from an email on the mailing list[1]) says this on the fn:collection function: fn:collection() either returns documents of a database or of the specified > location >From this it seems that it can return the documents of a specified location (without ever creating a database), however the following query: collection("<xml-dir>") reports the following error (using both the GUI and the command-line): [FODC0004] File or directory "File or directory "<basex>" not found." not > found. (Using Windows 7) I passed several kind of path to the collection function ("c:/xml-dir", "file:///c:/xml-dir", ...), but none of them works. Also, the actual path of "<basex>" in the error depends on whether I start the GUI (<basex>/BaseX.jar) or the command-line (<basex>/bin/basex.bat); the respective paths in these two cases are "<basex>" and "<basex>/bin". (Issuing something like doc("<xml-dir>/<xml-file>") works.) Is this the expected behavior? If yes, is that means that using BaseX one can only query multiple XML files after creating a database for them? If not, ... is this a bug? (I highly doubt.) (On a side note: something like DataDirect - supposedly - can do[2] would be awesome in BaseX. Was this ever considered to include in BaseX?) My reason for doing a query like this is: I've just tried to ran it and it didn't work, so I'm here. Thanks! Regards, Kohányi Róbert [1]: https://mailman.uni-konstanz.de/pipermail/basex-talk/2011-November/002213.h… [2]: http://www.xquery.com/tips_and_tricks/querying_multiple_documents.html

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Detecting abandoned locks
by Charles Duffy 09 Apr '12

09 Apr '12

Howdy -- I have a BaseX database with a pin-* file in its directory, reporting as locked and unavailable. However, OS-level tools such as fuser report that no programs have open file handles for any processes in this directory. What mechanism does BaseX use for detecting abandoned locks? It would be nice to use OS-level advisory locking where available, such that the lock is automatically released whenever the program holding it exits (or otherwise ceases to hold a handle on the file).

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Re: [basex-talk] basex 7.2.1 html5 serialization
by Andy Bunce 09 Apr '12

09 Apr '12

Ahh, yes it works for me too when I remember to deploy the code. Thanks /Andy On Mon, Apr 9, 2012 at 5:19 PM, Christian Grün <christian.gruen(a)gmail.com>wrote: > > My use is really with RESTXQ and following[1] I tried > > declare %rest:path("snipsnapx") %output:method("html") > > %output:doctype-system("about:legacy-compat") > > Thanks for the helpful link. With the following RESTXQ module.. > > module namespace rest = 'http://exquery.org/ns/restxq'; > declare %rest:path("") %output:method("html") > %output:doctype-system("about:legacy-compat") > function rest:start() { <html/> }; > > ..and the following request.. > > curl "http://admin:admin@localhost:8984/restxq" > > ..I get the following result.. > > <!DOCTYPE html SYSTEM "about:legacy-compat"> > <html></html> > > ..so all serializations options should also be supported by RESTXQ. > Which result would you expect? > Christian > > > > > > On Mon, Apr 9, 2012 at 1:52 PM, Christian Grün < > christian.gruen(a)gmail.com> > > wrote: > >> > >> Hi Andy, > >> > >> > The html5 serialization adds a doctype <!DOCTYPE html> but unlike > >> > method > >> > "html" it outputs empty tags for script. > >> > >> our announcement for announcing HTML5 was probably a little bit bold. > >> The sections for HTML5 support in the W3 XQuery Serialization > >> Specification [1] are still work in progress and not online yet, which > >> is why it may take a while until we will support all details of the > >> specification. > >> > >> > Also I cant get the REST eval to work. This url , for example, > >> > http://localhost:8984/rest/listman/add.xq always downloads rather > than > >> > executes, even though http://localhost:8984/rest/listman > >> > >> As there were numerous open issues related to the evaluation of XQuery > >> files located in database (such as the correct path resolution of > >> modules to be imported, and the fact that the evaluation of queries is > >> not very RESTful), we decided to get rid of this feature. Instead, > >> we'll soon be adding a richer framework (basex-web) to evaluate > >> queries server-side. In the meanwhile, you can use the RUN command to > >> evaluated queries located in the HTTP directory. > >> > >> Hope this helps, > >> Christian > >> > >> [1] http://www.w3.org/TR/xslt-xquery-serialization-30/ > >> ___________________________ > >> > >> On Mon, Apr 9, 2012 at 1:15 AM, Andy Bunce <bunce.andy(a)gmail.com> > wrote: > >> > Hi, > >> > Looks wrong to me. example below > >> > > >> > gives.. > >> > <rest:database name="listman" resources="1"><rest:resource type="raw" > >> > content-type="application/xquery" > >> > size="22">add.xq</rest:resource></rest:database> > >> > > >> > /Andy > >> > > >> > (: test html serialization :) > >> > declare option output:method "html5"; > >> > <html> > >> > <head> > >> > <script src="jquery-1.7.1.min.js" type="text/javascript"/> > >> > </head> > >> > </html> > >> > > >> > _______________________________________________ > >> > BaseX-Talk mailing list > >> > BaseX-Talk(a)mailman.uni-konstanz.de > >> > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > >> > > > > > >

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basex 7.2.1 html5 serialization
by Andy Bunce 09 Apr '12

09 Apr '12

Hi, The html5 serialization adds a doctype <!DOCTYPE html> but unlike method "html" it outputs empty tags for script. Looks wrong to me. example below Also I cant get the REST eval to work. This url , for example, http://localhost:8984/rest/listman/add.xq always downloads rather than executes, even though http://localhost:8984/rest/listman gives.. <rest:database name="listman" resources="1"><rest:resource type="raw" content-type="application/xquery" size="22">add.xq</rest:resource></rest:database> /Andy (: test html serialization :) declare option output:method "html5"; <html> <head> <script src="jquery-1.7.1.min.js" type="text/javascript"/> </head> </html>

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Module versioning for new packaging system
by Charles Duffy 08 Apr '12

08 Apr '12

Howdy -- For the most part, I'm glad to have the non-EXPath packaging mechanism introduced for 7.2.1 -- particularly given how the EXPath implementation in BaseX has some unintended side effects (ie. loading all modules when only one is referenced). However, I wonder if perhaps the current implementation could stand to be fleshed out a bit: - No mechanism for atomically upgrading a module exists; it must be uninstalled, then installed again, leaving an intermediate period in which the module is unavailable. - No mechanism for attaching a version to a module exists, making it impossible to determine whether an upgrade is necessary. The combination of these two factors is particularly unfortunate -- meaning that uninstallation/reinstallation is necessary when there is any conceivable possibility that a module may have changed (given the lack of a version registry), but not providing any means of performing such reinstallation without possible service disruption. With respect to versioning mechanism -- perhaps an optional pragma embedded in the module text, or an optional argument to 'REPO INSTALL'?

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Error: Improper use? Potential bug?
by Yves Roos 06 Apr '12

06 Apr '12

Query: for $n in //items/* let $p := $n/@publisher let $a := $n/@edition | $n/@label return if ($p) then delete nodes $a else if ($a) then ( rename node $a[1] as "publisher" , delete node $a[2]) else () Error: Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk(a)mailman.uni-konstanz.de Version: BaseX 7.2 Java: Apple Inc., 1.6.0_31 OS: Mac OS X, x86_64 Stack Trace: java.lang.ArrayIndexOutOfBoundsException: 2147483647 org.basex.io.random.TableDiskAccess.cursor(TableDiskAccess.java:401) org.basex.io.random.TableDiskAccess.read1(TableDiskAccess.java:115) org.basex.data.Data.kind(Data.java:309) org.basex.data.Data.delete(Data.java:659) org.basex.query.up.primitives.DeleteNode.apply(DeleteNode.java:35) org.basex.query.up.NodeUpdates.makePrimitivesEffective(NodeUpdates.java:216) org.basex.query.up.DatabaseUpdates.apply(DatabaseUpdates.java:148) org.basex.query.up.ContextModifier.applyUpdates(ContextModifier.java:58) org.basex.query.up.Updates.apply(Updates.java:188) org.basex.query.QueryContext.value(QueryContext.java:259) org.basex.query.QueryContext.iter(QueryContext.java:243) org.basex.query.QueryContext.execute(QueryContext.java:432) org.basex.query.QueryProcessor.execute(QueryProcessor.java:97) org.basex.core.cmd.AQuery.query(AQuery.java:91) org.basex.core.cmd.XQuery.run(XQuery.java:20) org.basex.core.Command.run(Command.java:345) org.basex.core.Command.exec(Command.java:324) org.basex.core.Command.execute(Command.java:76) org.basex.gui.GUI.exec(GUI.java:404) org.basex.gui.GUI$6.run(GUI.java:355) -- Yves Roos www.lifl.fr/~yroos

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Concurrency, maximum number of concurrent users / queries
by Peter Oostwoud-Sibiryak 05 Apr '12

05 Apr '12

Dear readers, I have a question about concurrency. In the documentation I read that the default amount of concurrent reads is 8. But as it seems quite low, is this "just a number", or is BaseX limited on this aspect? How many concurrent readers / writers does BaseX support? Would it be possible to use BaseX as a search system for a high visitor website, for example like Amazon? I read the documentation for a commercial supplier of XML database solutions EMC, and they have a nice document on this for their solution. http://www.emc.com/collateral/software/white-papers/h4662-xdb-performance-w… Thanks in advance for your answers. Best regards, Peter

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Exhausting PermGen space when using xar extensions w/ Java modules?
by Charles Duffy 05 Apr '12

05 Apr '12

Howdy -- I'm occasionally getting the following after a BaseX instance has been up and accepting queries for some time: [XPST0017] Class cannot be initialized: PermGen space. As I understand it, PermGen space is used during classloading. I'm using a Java extension (packaged in a xar); as BaseX has a fair bit of custom code around classloading, this seems the obvious first place to start looking. That said -- has anyone already seen this? (By the way -- without looking at the code, I would expect new classloading to only happen if the repo holding this plugin is being uninstalled and reinstalled; is this expectation accurate, or are plugins reloaded within a running instance more frequently?)

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BaseX-Talk April 2012