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

Large text files
by Tim Thompson 25 Nov '16

25 Nov '16

Hello, I have a large file[1] (3.5G unzipped) in the n-triples RDF format that I would like to work with in BaseX. When I try to read in the file using file:read-text(), I get the following error: Error: Version: BaseX 8.6 beta 8fa97ca Java: Oracle Corporation, 1.8.0_73 OS: Linux, amd64 Stack Trace: java.lang.NegativeArraySizeException at java.util.Arrays.copyOf(Arrays.java:3236) at org.basex.util.TokenBuilder.addByte(TokenBuilder.java:247) at org.basex.util.TokenBuilder.add(TokenBuilder.java:176) at org.basex.io.in.TextInput.cache(TextInput.java:143) at org.basex.io.in.TextInput.content(TextInput.java:132) at org.basex.query.value.item.StrStream.materialize(StrStream.java:71) at org.basex.query.value.item.StrStream.string(StrStream.java:44) at org.basex.query.expr.ParseExpr.toToken(ParseExpr.java:273) at org.basex.query.expr.ParseExpr.toEmptyToken(ParseExpr.java:261) at org.basex.query.func.fn.FnSubstring.item(FnSubstring.java:22) at org.basex.query.expr.ParseExpr.iter(ParseExpr.java:44) at org.basex.query.expr.gflwor.GFLWOR$1.next(GFLWOR.java:99) at org.basex.query.scope.MainModule$1.next(MainModule.java:122) at org.basex.query.QueryContext.cache(QueryContext.java:648) at org.basex.query.QueryProcessor.cache(QueryProcessor.java:116) at org.basex.core.cmd.AQuery.query(AQuery.java:87) at org.basex.core.cmd.XQuery.run(XQuery.java:22) at org.basex.core.Command.run(Command.java:255) at org.basex.core.Command.execute(Command.java:93) at org.basex.gui.GUI.exec(GUI.java:479) at org.basex.gui.GUI.access$3(GUI.java:433) at org.basex.gui.GUI$7.run(GUI.java:421) When I try to create a text database using the GUI, I get an error stating that the file could not be parsed. Is it possible to work with text files that are this large using BaseX? Thank you, Tim [1] Available for download here: http://www.bne.es/es/Inicio/Perfiles/Bibliotecarios/DatosEnlazados/Descarga… (http://datos.bne.es/datadumps/autoridades.nt.bz2) -- Tim A. Thompson Metadata Librarian (Spanish/Portuguese Specialty) Princeton University Library

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Re: [basex-talk] questions webfrontend icw BaseX-queryserver bachend
by Christian Grün 25 Nov '16

25 Nov '16

Hi Rob (cc to the list), > Thanx fort the quick reply. It sure helps but the db:output suggestion is not doing what I have in mind. > > - rest versus restxq. In that case I'll use the rest namespace. > - so it is a matter of choice. "Separation of concerns" would be my guideline in this. > - Yep, I want to return the save data to the client as a confirmation of the data that has been stored. This data is also enriched with f.e. an unique code. My problem with "db:output" is that the argument of the function is evaluated before the pending updates have been processed and I would like this evaluation take place on the updated data, like some kind of "reread"-functionality. I could not make this work with db:output. Am I overlooking something here? You are completely right, it is not possible to access the result of an update within the same query (because the pending updates will always be executed after query evaluation). This is what can be done instead: • You can use db:output(web:redirect(...)) to call another RESTXQ function that will generate the user feedback. This pattern is a good one for web applications anyway, because the result URL will be different from the updating URL. • An alternative is to create the result in main-memory and then a) write it to the database and b) pass it on to the client. Here is an arbitrary example: declare %updating %rest:POST %rest:path('/city/$city/$population') function local:update($city, $population) { let $city := db:open('factbook')//city[name = $city] let $updated-city := $city update { replace value of node population with $population } return ( replace node $city with $updated-city, db:output($updated-city) ) }; Does this help? Christian

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questions webfrontend icw BaseX-queryserver bachend
by Rob Stapper 24 Nov '16

24 Nov '16

Hi, I'm working on this POC of a XML-database application with a web based frontend in Basex. I have a few questions: - what is the difference between the rest- and the restxq- prefix? Do they refer to different namespaces? - should I call database-functions in the backend- server through a client-server connection? If I call the database functions directly from my restxq-functions it just works. But is this a correct configuration in a multi-user environment? - in case of adding or changing data in the database, is it possible to retrieve the saved data form the dababase in the same session and return it to the webpage? The saved data is enriched with f.e. an unique identification that I want to return to the webpage. TIA for yout reply. Rob Stapper

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"No function found that matches the request, " basexhttp, OS X El Capitan, and brew
by lambert strether 20 Nov '16

20 Nov '16

I first installed basex using the brew script recommended under "Other Distributions" here: http://basex.org/products/download/all-downloads/ basexgui worked fine, but when I ran basexhttp and went to localhost:8984 (and 127.0.0.1:8984) I got the following error: "No function found that matches the request" Rather than debug that, I uninstalled the brew installation and downloaded the BaseX 8.5.3.zip to my Home directory (/Users/...). Everything worked flawlessly out of the box, including basexhttp. Mac users: Don't worry about no *.dmg file. In my experience, the zip file should be fine (assuming your system requirements are fine, like an up-to-date Java). * * * Every communication from this account is off the record, unless explicitly put on the record.

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Re: [basex-talk] Restxq handling accept-encoding
by Kendall Shaw 18 Nov '16

18 Nov '16

I should clarify that I’m asking about content negotiation. %rest:produces is described as constraining based on the Accept header. Should I explicitly look for Accept-Encoding and produce binary data that is in one of the requested compressed formats, or is there something in basex’s restxq implementation that does this? Kendall From: <basex-talk-bounces(a)mailman.uni-konstanz.de> on behalf of Kendall Shaw <kendall.shaw(a)workday.com> Date: Tuesday, November 15, 2016 at 4:58 PM To: BaseX <basex-talk(a)mailman.uni-konstanz.de> Subject: [basex-talk] Restxq handling accept-encoding To return compressed text data, should I explicitly look for Accept-Encoding and use java to deflate or gzip output of convert:binary-to-string(db:retrieve(…))? Kendall

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Restxq handling accept-encoding
by Kendall Shaw 16 Nov '16

16 Nov '16

To return compressed text data, should I explicitly look for Accept-Encoding and use java to deflate or gzip output of convert:binary-to-string(db:retrieve(…))? Kendall

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Testing one data directory per tenant
by Maximilian Gärber 14 Nov '16

14 Nov '16

Hi, I am testing how to change DBPATH dynamically to enable a simple form of multi tenancy (running one basex instance with separated data directories, so locking for example does not affect all tenants). Basically, I just keep/reuse several Context objects which have other options set [1] String dbpath = ctx.soptions.get(StaticOptions.DBPATH); String userDbPath = dbpath + "\\" + usr; ctx.soptions.put(StaticOptions.DBPATH, userDbPath); So far, I did not experience any issues, anything that speaks against doing this? Regards, Max [1] https://github.com/axxepta/basex-multitenant/blob/master/src/test/java/de/a…

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Exporting large table from RDBMS
by Marco Lettere 14 Nov '16

14 Nov '16

Hi all, I'm currently facing the issue of exporting a large table stored in a MySQL instance to a csv that has then to be zipped and served through a web service. I'd love to use XQuery and the Basex functionality for doing it because it feels perfectly natural. The problem is that the XQuery script that performs the SQL Query and transformation to CSV crashes with an Out of Memory exception. I know how to increase memory and so on but I'd like to find a stable solution that is as less as possible dependent from the system requirements. Currently the only idea is to page the operation and (maybe exploiting parallel execution) build an intermediate result on disk files that will be assembled before delivery. Isn't there any more elegant solution based somehow on the streaming functionality or anything like this? Thanks for any advice you can provide. Regards, Marco.

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xquery result limit
by George Sofianos 12 Nov '16

12 Nov '16

Hi, I've found this very good answer to limiting results in xquery. http://stackoverflow.com/a/8900472/1951487 I like that it works, but I was wondering if you can explain what happens in the background? Thanks, George

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error when caling http service with latest Basex version ( Basex 8.6 beta baadd29)
by Rob Stapper 12 Nov '16

12 Nov '16

When calling the http-srvice through my browser with: http://robstapper.ddns.net:8984, I get an error-message from the service, see below, with the latest Basex version: Basex 8.6 beta baadd29. HTTP ERROR 500 Problem accessing /. Reason: Server Error Caused by: java.lang.NoSuchMethodError: org.basex.query.QueryContext.parse(Ljava/lang/String;Ljava/lang/String;Lorg/ basex/query/StaticContext;)Lorg/basex/query/Module; at org.basex.http.restxq.RestXqModule.qc(RestXqModule.java:120) at org.basex.http.restxq.RestXqModule.parse(RestXqModule.java:49) at org.basex.http.restxq.RestXqModules.cache(RestXqModules.java:189) at org.basex.http.restxq.RestXqModules.cache(RestXqModules.java:175) at org.basex.http.restxq.RestXqModules.cache(RestXqModules.java:175) at org.basex.http.restxq.RestXqModules.cache(RestXqModules.java:151) at org.basex.http.restxq.RestXqModules.find(RestXqModules.java:65) at org.basex.http.restxq.RestXqServlet.run(RestXqServlet.java:39) at org.basex.http.BaseXServlet.service(BaseXServlet.java:65) at javax.servlet.http.HttpServlet.service(HttpServlet.java:848) at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:684) at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:503) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:137 ) at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:557) at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java :231) at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java :1086) at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:429) at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java: 193) at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java: 1020) at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:135 ) at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:1 16) at org.eclipse.jetty.server.Server.handle(Server.java:370) at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpCo nnection.java:494) at org.eclipse.jetty.server.AbstractHttpConnection.headerComplete(AbstractHttpC onnection.java:971) at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.headerComplet e(AbstractHttpConnection.java:1033) at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:640) at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:231) at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java :82) at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint. java:696) at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.j ava:53) at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java: 608) at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:5 43) at java.lang.Thread.run(Unknown Source) _____ Powered by Jetty://

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