BaseX-Talk

basex-talk@mailman.uni-konstanz.de

1 participants
5252 discussions

BaseX start up questions
by Erik F. Andersen 24 Mar '13

24 Mar '13

Hello all, first of all I'm sorry if this become a repost but I don't think that my mail made it the first time... I'm considering BaseX for a project of mine but before I go any further I have a few questions. First some facts: - I need to store up to perhaps 50.000 documents in each database (collection) at about 1MB in average size. - One database will be queried of up to 5 users at a time on average, each one issuing 50 times more reads than writes. I would say perhaps 50 rather simple reads (queries) a minute (most queries will be done against a single document at a time). - Ideally each server should host up to 50 such databases. Now to my questions: 1) Will the number of databases have a performance hit (degredation) on the system as a whole other than that caused be the extra number of concurrent users? 2) Can I expect a performance hit on a given database related to the number of concurrent users on that database, even if those users are mostly quering different documents? 3) Will the number of documents in a given database have a performance hit on queries done against that database? 4) Are there any limitations in BaseX that I should possibly be aware of? I would also like to know what my options are for backing up the databases (preferably while in use), and what I can do to repair a database if a document somehow become corrupted due to a software malfunction? Finally I would like to hear if BaseX is being used for other critical applications other than mine where stability and fast response times is essential? Thank you for your time, Regards Erik

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Re: [basex-talk] Out of Main Memory
by Hans-Juergen Rennau 22 Mar '13

22 Mar '13

Dear Fabrice, thank you for your response! The crash happened during db creation (using db:create). Interesting idea to disable indexes - I will try this out. Hans-Juergen ________________________________ Von: Fabrice Etanchaud <fetanchaud(a)questel.com> An: Hans-Juergen Rennau <hrennau(a)yahoo.de> Gesendet: 14:08 Freitag, 22.März 2013 Betreff: RE: [basex-talk] Out of Main Memory Dear Hans-Juergen, Did it happen during db creation, or during index creation (in that case, the collection is available and can be opened) ? With big collections like this, I usually disable indices before creation, and create them later. Best, Fabrice

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Out of Main Memory
by Hans-Juergen Rennau 22 Mar '13

22 Mar '13

Dear BaseX team, trying to create a database from a document with a size of 6.5 GB I get this error: "Out of Main Memory". Using the latest snapshot. Could this be expected? I suppose that data loading is done in a streaming fashion? Is there something I can do to upload a doc of that size? Thank you very much for hints, Hans-Juergen

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Using BaseX in Java - doc?
by Florent Georges 22 Mar '13

22 Mar '13

Hi, I was looking on http://docs.basex.org/ after documentation on integrating BaseX within a Java application, but couldn't find any. Did I miss them? In a few words, I have a Java webapp running in Tomcat, and I'd like to use a BaseX database for the storage. Can I embed it completely? Do I have to start a server as a completely separate process? Regards, -- Florent Georges http://fgeorges.org/ http://h2oconsulting.be/

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reverse proxy basex behind nginx
by pw＠themail.co.uk 21 Mar '13

21 Mar '13

Hello List I have basex 7.7 beta running in http server mode with httplocal = false. Access and searches either with the client direct to the BaseX server, or via restxq called directly on the server are a few tens of milliseconds. I have the BaseX httpserver accessible to the external network through a nginx reverse proxy. traceroute shows that a call gets to the machine in about 120ms. However, access and searches of the Basex database from the network are in the order of tens of seconds. I would appreciate details of more successful proxying, and also any hints on the nginx - basex coupling. Many thanks Peter

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store results of a query in a new database
by Cerstin Elisabeth Mahlow 21 Mar '13

21 Mar '13

Hi, I would like to store the results of an xquery extracting some nodes from an existing database into a new database. So I have the DB 'collect' open and then do: db:create('annotate-abcdef') and then for $i at $p in //entry[phraseme[text() = "abcdef"] and selected[text() = "yes"]] let $query := $i/query let $nodeid := $i/node let $node := db:open-id('TG-DTA-GerManC-stemming-ws', $nodeid) let $nodename := name($node) let $nodecontent := string($node) return insert node <div>{$nodeid} {$query} {element {$nodename} {$nodecontent}} </div> as last into db:open('annotate-abcdef') However, the error message is [XUDY0027] Insert target must not be empty. How would I add a root element to the new DB, as I don't wan't to link it to an existing document? All nodes added to the DB are only results from queries over an existing DB. All I can see from the Wiki is using a document as initial data for the DB. How do I set UPDINDEX ON for the new DB? I will later update the information added in the first place by other queries. To be able to use ft:mark, I would have to optimize the DB with db:optimize() after having added nodes, is this correct? Thanks in advance and best regards Cerstin -- Dr. phil. Cerstin Mahlow Universität Basel Departement Sprach- und Literaturwissenschaften Fachbereich Deutsche Sprach- und Literaturwissenschaft Nadelberg 4 4051 Basel Schweiz Tel: +41 61 267 07 65 Fax: +41 61 267 34 40 Mail: cerstin.mahlow(a)unibas.ch Web: http://www.oldphras.net

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[UPDINDEX] db:add bug
by Fabrice Etanchaud 21 Mar '13

21 Mar '13

Dear all, The following list of commands/queries lead to a bug report : Set updindex true Create db mydb db:add('mydb',<root/>,'mydb.xml') Error: Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk(a)mailman.uni-konstanz.de Version: BaseX 7.7 beta Java: Oracle Corporation, 1.7.0_15 OS: Windows 7, amd64 Stack Trace: java.lang.NullPointerException org.basex.data.Data.insert(Data.java:840) org.basex.query.up.primitives.DBNew.addDocs(DBNew.java:57) org.basex.query.up.primitives.DBAdd.prepare(DBAdd.java:49) org.basex.query.up.DatabaseUpdates.check(DatabaseUpdates.java:109) org.basex.query.up.ContextModifier.apply(ContextModifier.java:89) org.basex.query.up.Updates.apply(Updates.java:120) org.basex.query.QueryContext.update(QueryContext.java:281) org.basex.query.QueryContext.value(QueryContext.java:265) org.basex.query.QueryContext.iter(QueryContext.java:250) org.basex.query.QueryContext.execute(QueryContext.java:499) org.basex.query.QueryProcessor.execute(QueryProcessor.java:96) org.basex.core.cmd.AQuery.query(AQuery.java:77) org.basex.core.cmd.XQuery.run(XQuery.java:22) org.basex.core.Command.run(Command.java:342) org.basex.core.Command.exec(Command.java:321) org.basex.core.Command.execute(Command.java:78) org.basex.gui.GUI.exec(GUI.java:397) org.basex.gui.GUI$7.run(GUI.java:349) Query plan: <QueryPlan> <FNDb name="add(database,input[,path])"> <Str value="mydb" type="xs:string"/> <CElem> <QNm value="root" type="xs:QName"/> </CElem> <Str value="mydb.xml" type="xs:string"/> </FNDb> </QueryPlan> Have a nice week-end. Fabrice

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some stackrelated questions
by Rob Stapper 18 Mar '13

18 Mar '13

Hi, My recursive query gives a stackoverflow: [XQDY0054] Stack Overflow: circular variable declaration? I use the standard, standalone BaseX-software. I'm almost certain it isn't a circular variable declaration because this recursive query can go pretty deep, probably more than a hundred levels and maybe even more. It works on smaller files but it gives this message on the biggest files with the deepest nestinglevel. How deep is the nestinglevel of recursive-queries in BaseX? How can the the max. nestinglevel be increased? Thnx in advance for your reply. Sincerely Rob Stapper

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Re: [basex-talk] seeking for a document in a collection with a million documents is very slow
by Fabrice Etanchaud 18 Mar '13

18 Mar '13

Dear all, >From what I read in the documentation, My problem seems to be related to the update of the resource index. Is this index updated after each add/replace/delete command, Or at the end of the commands' list ? Last, could you please tell me if replace is equivalent to delete+add ? Best, Fabrice De : Fabrice Etanchaud Envoyé : vendredi 15 mars 2013 14:18 À : 'basex-talk(a)mailman.uni-konstanz.de' Objet : seeking for a document in a collection with a million documents is very slow Dear all, Does the document index rely on text or attribute index ? One can experiment very slow response time when looking for a specific document name in an optimized collection of a million documents (in dynamic execution, without optimizations, for example within a loop with a name being the concatenation of string values). Is there a way to speed things up ? Best regards, Fabrice Etanchaud Questel-orbit

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Copy Command
by John Best 18 Mar '13

18 Mar '13

Hi there, I am trying to Copy the "Doc" DB using following piece of code - try{ ....... new Copy("Doc", "Doc1").execute(CONTEXT); ....... ....... } catch(........ .......................... I am expecting another copy of Doc db as Doc1 db... Am I right..? But can't see "Doc1" anywhere... No error mesg... !! -- Have a nice day JBest

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