BaseX-Talk

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5252 discussions

concurrent issues with 7.5 - OverlappingFileLockException
by Srinivasan Muthu 18 Nov '12

18 Nov '12

Hi, We started having some thread hanging issues when concurrent calls were being made to our basex 7.3 database (client-server mode) from java 6 web app on Mac (less prominent in Windows). We extracted the code into a simple java app to test this in two threads executing a simple doc('blah') command several times and were able to reproduce the thread hanging issue easily in basex 7.3. After Christian's suggestion in another forum conversation to use 7.5, we tried with 7.5, now the code does not hang but it throws java.nio.channels.OverlappingFileLockException frequently for some of the db requests. I am attaching the sample java program here as a jar file (source code inside as well). Here is a sample output of this program: Srini-MacBook-Pro:Downloads srini$ java -jar BasexTest.jar the time the xxxxxxxx 1 time the time the xxxxxxxx 2 time . . (some output lines hidden here for brevity) . the time the xxxxxxxx 30 time the time the xxxxxxxx 31 time java.io.IOException: java.nio.channels.OverlappingFileLockException at com.vmware.gts.vha.basex.BaseXClient$Query.exec(BaseXClient.java:446) at com.vmware.gts.vha.basex.BaseXClient$Query.execute(BaseXClient.java:405) at com.vmware.gts.vha.test.ParallelExecution.runXQuery(ParallelExecution.java:33) at com.vmware.gts.vha.test.ParallelExecution.access$0(ParallelExecution.java:30) at com.vmware.gts.vha.test.ParallelExecution$SampleRunnable.run(ParallelExecution.java:13) at java.lang.Thread.run(Thread.java:680) Is this a potential bug in BaseX 7.5? This issue is more prominent (happens frequently) in Mac than Windows. We tried with both DBLocking=true and false and the issue remains. Thanks, Srini

2 4

Re: [basex-talk] BUG# Multiple Thread try to execute some Query
by Samuel Lacmene 18 Nov '12

18 Nov '12

2 1

udpindex
by Mahlow Cerstin 17 Nov '12

17 Nov '12

Hi, as far as I can see, UPDINDEX cannot be set in the GUI when creating a database. Is this correct? So how would I proceed to change my existing database created without this option and updated and queried by users constantly into an database with this option to make retrieval faster? Is it correct that with UPDINDEX true there is no need anymore to "optimize" the index from time to time? Initially I thought of exporting the existing DB as XML and then using this as source for a new DB with UPDINDEX set true. How do I do this without the GUI? Oh, and could you please make it possible to choose UPDINDEX as an option in the GUI? Best regards Cerstin -- Dr. phil. Cerstin Mahlow Universität Basel Deutsches Seminar 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

3 2

Updating single database locks entire server
by Srinivasan Muthu 17 Nov '12

17 Nov '12

First of all, great work you guys, thanks much. We use BaseX 7.3 in client/server mode for concurrency purposes and have several databases. We have an updating function which updates the XML database after the initial creation to make sure the attributes are setup for faster querying. Here is the function: declare updating function local:processVMs($dbName as xs:string){ let $doc := doc($dbName) let $vms := $doc/root/proj/VM return if (empty($vms/@desktopId)=true()) then ( for $vm in $vms let $desktopId := local:get-desktop-id-from-vm($vm) (: function not provided here:) return insert node (attribute {'desktopId'} {string($desktopId)}, 'text', <VM/>) into $vm) else () }; This function takes a minute to run when there are about 3000 objects. While this query runs, BaseX queues all other xqueries (including read xqueries on other databases too) and thereby rendering the server unresponsive until this update query is done. Due to this even the queries that are running on other databases become unresponsive and our application looks frozen until this update query is done.From reading old email archives here, I see that BaseX transaction monitor will queue all requests when update query is processed as multiple dbs can be updated using one xQuery. Is this really true and is there any way to hint transaction monitor to lock only the database that is being updated and not the entire server? Thanks, Srini

2 5

performance and collections
by pw＠themail.co.uk 15 Nov '12

15 Nov '12

dear list I have a web-based database (basex 7.5 running on tomcat) in which I have a collection with about 3000 files in various sizes from about 1k to 40k. Would I get better performance by splitting these files across several collections? what are the rules of thumb here? many thanks Pete

2 1

XQuery web app authentication - best practices?
by Daniel Kvasnička 15 Nov '12

15 Nov '12

Hi folks, I'd like to write an app using RESTXQ and I'd like to auth users using a regular form-based authentication and then on some XQuery functions check for an existing user session (and possibly user roles). I'd also like to add some social media login using OAuth (later). My question is - is it somehow possible to do this in a declarative way? For example custom annotations on XQuery handlers? Something like %auth:roles-allowed("admin") I definetly don't want to "if" at the beginning of every function that should be protected. No problem with implementing this in Java or XQuery. Just tell me how to approach this orthogonal concern in a reasonable way... Or should I equal app users to BaseX users and leverage Basex auth? Any tips appreciated (yes, you can even tell me BaseX RESTXQ is not a good tool for that). Daniel -- danielkvasnicka.net

4 5

Options in Basex 7.5
by Andy Bunce 15 Nov '12

15 Nov '12

There are many ways to set options [1] but it is not clear to me which one wins in the case where different values are specified for the same option by the different ways. I guess it is the 1st one to be set. So SystemProperty, then command line, then .basex? I am often getting caught out by the fact that in recent 7.5 builds the http properties are ignored unless they are set by editing jetty.xml. I wonder if the supplied jetty.xml could use <SystemProperty>. Something like: <New class="org.eclipse.jetty.server.nio.SelectChannelConnector">  <Set name="host"><SystemProperty name="org.basex.serverhost" default=""/></Set> <Set name="port"><SystemProperty name="org.basex.serverport" default="8984"/></Set> <Set name="confidentialPort"><SystemProperty name="org.basex.??" default="??"/></Set> <Set name="maxIdleTime">60000</Set> <Set name="reuseAddress">false</Set> <Set name="Acceptors">2</Set> </New> /Andy [1] http://docs.basex.org/wiki/Options

2 3

for ... group by - minor bug
by Hans-Juergen Rennau 15 Nov '12

15 Nov '12

Hello, the support for XQuery 3.0 is really wonderful! Thank you. Just a trifle: I think there is a little bug concerning the "group by" clause and the case that a non-grouping variable is reused as grouping variable, but the shorthand notation for this is not used. According to the spec, these expressions should be equivalent: group by $x group by $x := $x I observed that in the shorthand notation $x references the grouping variable, that is, one value per group, as it should. But in the longhand notation, $x references the variable in the pre-grouping variable, and I suppose this should not be so. For a full example, see below. Kind regards, Hans-Juergen PS: Full example: Code: for $x in (1, 1, 2) group by $x := $x return <r x="{$x}"/> Output: <r x="1 1"/> <r x="2"/>

1 0

sql query result - formated xml from mysql database
by Jarosław Kowalewski 15 Nov '12

15 Nov '12

Hi, I've in my mysql database field with xml (formated xml). By using sql module i get something like that: <sql:column xmlns:sql="http://basex.org/modules/sql" name="xml"> <?xml version="1.0" encoding="UTF-8"?> <Document xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="wniosek.xsd"> </Document> and I can't query it like regular xml by xquery. It's possible to get only content of xml column? Or it's other way to query this content? Jarek

2 2

Re: [basex-talk] xquery sql module init driver
by Jarosław Kowalewski 15 Nov '12

15 Nov '12

Thanks a lot. That works!:) Mayby it's a good idea to write about that in manual or FAQ? Jarek 2012/11/15 <basex-talk-request(a)mailman.uni-konstanz.de>: > Message: 4 > Date: Wed, 14 Nov 2012 15:55:34 +0100 (CET) > From: Antoni Mylka <amy(a)basis06.ch> > To: basex-talk <basex-talk(a)mailman.uni-konstanz.de> > Subject: Re: [basex-talk] xquery sql module init driver > Message-ID: <701444465.74583.1352904934339.JavaMail.root(a)basis06.ch> > Content-Type: text/plain; charset=utf-8 > > Hi Jarek, > > And what about > > java -cp pathto/mysql-connector-java-5.1.21-bin.jar:BaseX73.jar org.basex.BaseXGUI > > ? > > quoting from: > > http://stackoverflow.com/questions/945962/java-problem-running-a-jar-file-i… > > "If you're running a jar file with java -jar, the -classpath argument is ignored." > > -- > Antoni My?ka > Software Engineer > > basis06 AG, Birkenweg 61, CH-3013 Bern - Fon +41 31 311 32 22 > http://www.basis06.ch - source of smart business > > ----- Urspr?ngliche Mail ----- > Von: "Jaros?aw Kowalewski" <jaroslaw.kowalewski(a)students.waw.pl> > An: basex-talk(a)mailman.uni-konstanz.de > Gesendet: Mittwoch, 14. November 2012 13:16:37 > Betreff: [basex-talk] xquery sql module init driver > > Hi, > I try to connect with my database directly by sql module. > > sql:init("com.mysql.jdbc.Driver"), > > let $conn := sql:connect("jdbc:mysql://dbhost:port/dbname") > return sql:execute($conn, "SELECT * FROM coffees WHERE price < 10") > > but I've problem with and I get error "[BXSQ0007] Could not initialize > specified driver: 'com.mysql.jdbc.Driver'" > > java -cp pathto/mysql-connector-java-5.1.21-bin.jar -jar BaseX73.jar > > Thanks for a help > > Jarek >

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