BaseX-Talk May 2018

basex-talk@mailman.uni-konstanz.de

28 participants
38 discussions

Duplicate declaration of static variable
by Andreas Mixich 14 May '18

14 May '18

Hi, when loading my RESTXQ app I get this: Stopped at C:/Users/dev/.jetty/webapps/basex/fwdev/lib/account.xqm, 20/18: [XQST0049] Duplicate declaration of static variable $acc:last-visited. dev@mambo ~/.jetty/webapps/basex $ grep -R --include="*.*" "\$acc\:last-visited" . ./fwdev/lib/account.xqm:declare variable $acc:last-visited as xs:dateTime? external := (); As it seems, there is no other declaration of the variable in the whole project. What could that be? -- Goody Bye, Minden jót, Mit freundlichen Grüßen, Andreas Mixich

2 1

Re: [basex-talk] 9.0.1: High Memory Usage Loading Docs Via GUI
by Eliot Kimber 14 May '18

14 May '18

Follow up--I tried giving BaseX the full 16GB of RAM and it still ultimately locked up with the memory meter showing 13GB. I'm thinking this must be some kind of memory leak. I tried importing the DITA Open Toolkit's documentation source and that worked fine with the max memory being about 2.5GB, but it's only about 250 topics. Cheers, E. -- Eliot Kimber http://contrext.com On 5/3/18, 4:59 PM, "Eliot Kimber" <basex-talk-bounces(a)mailman.uni-konstanz.de on behalf of ekimber(a)contrext.com> wrote: In the context of trying to do fun things with DITA docs in BaseX I downloaded the latest BaseX (9.0.1) and tried creating a new database and loading docs into it using the BaseX GUI. This is on macOS 10.13.4 with 16GB of hardware RAM available. My corpus is about 4000 DITA topics totaling about 30MB on disk. They are all in a single directory (not my decision) if that matters. Using the "parse DTDs" option and default indexing options (no token or full text indexes) I'm finding that even with 12GB of RAM allocated to the JVM the memory usage during load will eventually go to 12GB, at which point the processing appears to stop (that is, whatever I set the max memory to, when it's reached, things stop but I only got out of memory errors when I had much lower settings, like the default 2GB). I'm currently running a test with 14GB allocated and it is continuing but it does go to 12GB occasionally (watching the memory display on the Add progress panel). No individual file is that big--the biggest is 150K and typical is 30K or smaller. I wouldn't expect BaseX to have this kind of memory problem so I'm wondering if maybe there's an issue with memory on macOS or with DITA documents in particular (the DITA DTDs are notoriously large)? Should I expect BaseX to be able to load this kind of corpus with 14GB of RAM? Cheers, E. -- Eliot Kimber http://contrext.com

2 7

Unexpected unary lookup result
by Sebastian Zimmer 14 May '18

14 May '18

Hi, I have this script where I use the lookup operator to perform a unary lookup: xquery version "3.1"; declare namespace array = "http://www.w3.org/2005/xpath-functions/array"; let $array := [] return ( empty($array!?*), (: returns false :) empty( for $i in 1 to array:size($array) return $array($i) ) (: returns true :) ) I'm curious that the first expression returns false even though it should be equivalent to the second expression, if I read the XQuery spec [1] right: If the context item is an array: If theKeySpecifier <https://www.w3.org/TR/2017/REC-xquery-31-20170321/#doc-xquery31-KeySpecifier>is a wildcard ("|*|"), theUnaryLookup <https://www.w3.org/TR/2017/REC-xquery-31-20170321/#doc-xquery31-UnaryLookup>operator is equivalent to the following expression: for $k in 1 to array:size(.) return .($k) But maybe I'm missing something. I'd be glad if you could help. Best regards, Sebastian Zimmer [1] https://www.w3.org/TR/2017/REC-xquery-31-20170321/#id-unary-lookup -- Sebastian Zimmer sebastian.zimmer(a)uni-koeln.de <mailto:sebastian.zimmer@uni-koeln.de> CCeH Logo <http://cceh.uni-koeln.de> Cologne Center for eHumanities <http://cceh.uni-koeln.de> DH Center at the University of Cologne Twitter Logo <https://twitter.com/CCeHum>@CCeHum <https://twitter.com/CCeHum>

3 6

BaseX weird error
by halit tiryaki 09 May '18

09 May '18

Hello, got a serious problem here. any ideas? thanks Improper use? Potential bug? Your feedback is welcome: Contact: basex-talk(a)mailman.uni-konstanz.de Version: BaseX 9.0.2 beta Java: Oracle Corporation, 1.8.0_151 OS: Linux, amd64 Stack Trace: java.lang.ArrayIndexOutOfBoundsException: 4288 at org.basex.io.random.TableDiskAccess.read1(TableDiskAccess.java:151) at org.basex.data.Data.kind(Data.java:294) at org.basex.query.value.node.DBNode$4.next(DBNode.java:332) at org.basex.query.value.node.DBNode$4.next(DBNode.java:323) at org.basex.query.expr.path.IterStep$1.next(IterStep.java:38) at org.basex.query.expr.path.IterStep$1.next(IterStep.java:32) at org.basex.query.QueryContext.next(QueryContext.java:392) at org.basex.query.expr.path.IterPath$1.next(IterPath.java:50) at org.basex.query.expr.path.IterPath$1.next(IterPath.java:34) at org.basex.query.expr.ParseExpr.item(ParseExpr.java:58) at org.basex.query.expr.ParseExpr.atomItem(ParseExpr.java:84) at org.basex.query.func.fn.FnConcat.item(FnConcat.java:20) at org.basex.query.expr.ParseExpr.value(ParseExpr.java:71) at org.basex.query.expr.gflwor.Let$LetEval.next(Let.java:177) at org.basex.query.expr.gflwor.GFLWOR.value(GFLWOR.java:72) at org.basex.query.expr.path.CachedPath.nodeIter(CachedPath.java:36) at org.basex.query.expr.path.AxisPath.iter(AxisPath.java:69) at org.basex.query.expr.gflwor.For$1.next(For.java:107) at org.basex.query.expr.gflwor.OrderBy$1.sort(OrderBy.java:73) at org.basex.query.expr.gflwor.OrderBy$1.next(OrderBy.java:54) at org.basex.query.expr.gflwor.GFLWOR.value(GFLWOR.java:72) at org.basex.query.expr.gflwor.Let$LetEval.next(Let.java:177) at org.basex.query.expr.gflwor.GFLWOR$1.next(GFLWOR.java:87) at org.basex.query.QueryContext.next(QueryContext.java:392) at org.basex.query.scope.MainModule$1.next(MainModule.java:122) at org.basex.core.cmd.AQuery.query(AQuery.java:94) at org.basex.core.cmd.XQuery.run(XQuery.java:22) at org.basex.core.Command.run(Command.java:257) at org.basex.core.Command.execute(Command.java:93) at org.basex.server.ClientListener.run(ClientListener.java:140)

2 1

Distributed XML processing on Apache Spark
by Andrey Yatsuk 08 May '18

08 May '18

Hello. Briefing: I want to implement distributed work with BaseX in Hadoop using Apache Spark. Data processing will be divided into the following stages: 1) Splitting XML into chunks 2) Parallel parsing and filling the database 3) Executing queries to make the table (Apache Spark Dataset<Row>) Stage 1 is a simple algorithmic problem. It will compose a HashMap of (ChunkNumber -> List<Xml_Path>). Each chunk contains no more than 128 MB of data. Step 2. On each node of the cluster will initialized a standalone instance of BaseX. Every instance of BaseX will recieve files / lines from HDFS to the input. A xml database of each chunk as result will be serialized to HDFS. Stage 3. When the request of a query is received, each xml database will be sequentially deserialized to apply the query. A table will be composed from the result. Questions: 1) Send data from HDFS to embedded BaseX: 1.1) Does BaseX support reading data by schemed URI, e.g. `hdfs://home/user/file.xml`? 1.2) Can I send XML from RAM to BaseX? 1.3) Can I send XML lines (line by line) to BaseX? 2) Can I get a database in ram to serialize it in HDFS? 3.1) Do I need to store XML in a persistent path to query it in the future? 3.2) When executing a query on XML in HDFS, can I read it line by line if BaseX does not know how to work with it directly? Best regards, Andrei Iatsuk.

2 1

How to export a database containing xi:include to multiple files
by Marco Randazzo 07 May '18

07 May '18

Hello, I used baseX gui to create a database from the following test file: <main xmlns:xi="http://www.w3.org/2001/XInclude"> <xi:include href="folder1/file1.xml" /> <xi:include href="folder2/file1.xml" /> </main> The Result of the baseX gui is correct: <main xmlns:xi="http://www.w3.org/2001/XInclude"> <data xml:base="folder1/file1.xml">5555</data> <data xml:base="folder2/file1.xml">6666</data> </main> Now, after editing the values, I would like to export the contents of the database to xml files, recreating the same folders and files (I see this information stored in the value of xml:base) However, using the export function available in the GUI, I am able only to obtain a single file containing the Result shown above. What should I do? Thank you Cheers Marco Randazzo

2 1

9.0.1: High Memory Usage Loading Docs Via GUI
by Eliot Kimber 03 May '18

03 May '18

In the context of trying to do fun things with DITA docs in BaseX I downloaded the latest BaseX (9.0.1) and tried creating a new database and loading docs into it using the BaseX GUI. This is on macOS 10.13.4 with 16GB of hardware RAM available. My corpus is about 4000 DITA topics totaling about 30MB on disk. They are all in a single directory (not my decision) if that matters. Using the "parse DTDs" option and default indexing options (no token or full text indexes) I'm finding that even with 12GB of RAM allocated to the JVM the memory usage during load will eventually go to 12GB, at which point the processing appears to stop (that is, whatever I set the max memory to, when it's reached, things stop but I only got out of memory errors when I had much lower settings, like the default 2GB). I'm currently running a test with 14GB allocated and it is continuing but it does go to 12GB occasionally (watching the memory display on the Add progress panel). No individual file is that big--the biggest is 150K and typical is 30K or smaller. I wouldn't expect BaseX to have this kind of memory problem so I'm wondering if maybe there's an issue with memory on macOS or with DITA documents in particular (the DITA DTDs are notoriously large)? Should I expect BaseX to be able to load this kind of corpus with 14GB of RAM? Cheers, E. -- Eliot Kimber http://contrext.com

1 0

XInclude and Catalog resolution
by Andreas Mixich 02 May '18

02 May '18

Hello, am I right, that both XML catalogs and XIncludes get only evaluated at document import, not at XQuery execution? If I do declare base-uri "http://example.com/restxq-framework/src/"; let $file := doc("fragments/xhtml5-page.xhtml") return $file and I have an XML Catalog entry like this: <uri id="RESTXQ-Famework" name="http://example.com/restxq-framework/src/" uri="file:///S:/projects/restxqfr/src/"/> or this: <rewriteSystem id="RESTXQ-Famework" systemIdStartString="http://example.com/restxq-framework/src/" rewritePrefix="file:///S:/projects/restxqfr/src/" /> BaseX tries to load the 'fragments/xhtml5-page.xhtml' from 'example.com/restxq-framework/src/' -- Goody Bye, Minden jót, Mit freundlichen Grüßen, Andreas Mixich

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BaseX-Talk May 2018