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

possible bug - using inline functions in unit tests
by Jan Techter 25 Mar '14

25 Mar '14

Dear basex team, running the following unit test involving a simple anonymous function declare %unit:test function local:test-inline-function() { let $f := function($x) {$x+1} return unit:assert-equals( $f(5), 6) }; raises a java exception [exec] Improper use? Potential bug? Your feedback is welcome: [exec] Contact: basex-talk(a)mailman.uni-konstanz.de [exec] Version: BaseX 7.8 [exec] Java: Oracle Corporation, 1.7.0_51 [exec] OS: Linux, i386 [exec] Stack Trace: [exec] java.lang.ClassCastException: org.basex.query.value.type.AtomType cannot be cast to org.basex.query.value.type.FuncType [exec] at org.basex.query.func.InlineFunc.item(InlineFunc.java:261) [exec] at org.basex.query.func.InlineFunc.value(InlineFunc.java:280) [exec] at org.basex.query.QueryContext.value(QueryContext.java:367) [exec] at org.basex.query.gflwor.Let$LetEval.next(Let.java:230) [exec] at org.basex.query.gflwor.GFLWOR$2.next(GFLWOR.java:73) [exec] at org.basex.query.iter.Iter.value(Iter.java:64) [exec] at org.basex.query.expr.ParseExpr.value(ParseExpr.java:71) [exec] at org.basex.query.QueryContext.value(QueryContext.java:367) [exec] at org.basex.query.func.StaticFunc.invValue(StaticFunc.java:203) [exec] at org.basex.query.func.FuncCall.invoke(FuncCall.java:96) [exec] at org.basex.query.func.FuncCall.value(FuncCall.java:138) [exec] at org.basex.query.func.StaticFunc.invokeValue(StaticFunc.java:215) [exec] at org.basex.query.util.unit.Unit.eval(Unit.java:210) [exec] at org.basex.query.util.unit.Unit.test(Unit.java:127) [exec] at org.basex.query.util.unit.Unit.test(Unit.java:51) [exec] at org.basex.query.func.FNUnit.test(FNUnit.java:100) [exec] at org.basex.query.func.FNUnit.item(FNUnit.java:40) [exec] at org.basex.query.expr.ParseExpr.iter(ParseExpr.java:46) [exec] at org.basex.query.MainModule.iter(MainModule.java:96) [exec] at org.basex.query.QueryContext.iter(QueryContext.java:310) [exec] at org.basex.query.QueryProcessor.iter(QueryProcessor.java:81) [exec] at org.basex.core.cmd.AQuery.query(AQuery.java:89) [exec] at org.basex.core.cmd.XQuery.run(XQuery.java:22) [exec] at org.basex.core.Command.run(Command.java:329) [exec] at org.basex.core.Command.execute(Command.java:94) [exec] at org.basex.server.LocalSession.execute(LocalSession.java:121) [exec] at org.basex.server.Session.execute(Session.java:37) [exec] at org.basex.core.Main.execute(Main.java:146) [exec] at org.basex.BaseX.<init>(BaseX.java:119) [exec] at org.basex.BaseX.main(BaseX.java:38) [exec] updating to basex 7.8.1 didnt make any difference. Is this a bug? Best regards. Jan

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XML clob w/ SQL module
by Bednar, Scott E 25 Mar '14

25 Mar '14

I'm trying to extract XML stored in a CLOB from an oracle database using the sql module for BaseX. When I select the clob value, I get this sort of thing: <sql:column name="MSG">oracle.sql.CLOB@49458ef3</sql:column> I've tried casting it to XMLType (similar message) and to char (buffer size too small for the XML I'm dealing with). Is there a way of doing this short of creating a specialized Java module for it? Thanks, Scott

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Re: [basex-talk] multi-threaded XQueries
by Christian Grün 25 Mar '14

25 Mar '14

Hi Ying, > e.g. the dataset I use is DBLP, one of the example query is > > for $x in db:open('dblp_2013')/dblp/article[child::pages and child::title] > let $y := count($x/author) > return concat($y, "/t", db:node-id($x)) Yes, I agree there is not much that can be done to speed up this query. > It is true that these queries are competing for the same resource. > So you mean that each query causes a lot of disk I/O? Exactly. All DBLP articles need to be parsed by this query, and > 1 million result strings will be generated, resulting in a query time of appr. 0.005 ms per result. Hope this helps, Christian > However all these queries are read-only. It there any room to improve this? > -- > Regards > > Shanshan > > School of Computing > National University of Singapore

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BaseX: Upcoming Features
by Christian Grün 24 Mar '14

24 Mar '14

Dear BaseX aficionados, An upcoming version of our software (7.9 or 8.0) will make it much easier to perform updates and return items at the same time [1]. It will also contain an xquery:update function and will bring xquery:eval and xquery:evaluate together again [2] Another exciting and sophisticated feature we are working on is query precompilation [3], which will particularly speed up large XQuery applications and allow for more request-specific optimizations. Next, we are working on a Database Administration interface based on RESTXQ, and we will also drop out the confusing client/server dialog from the GUI. Feature 1 and 2 are already available via a feature branch [4]. If you are working with the git sources, we are excited to get your feedback! Christian [1] https://github.com/BaseXdb/basex/issues/873 [2] https://github.com/BaseXdb/basex/issues/878 [3] https://github.com/BaseXdb/basex/issues/874 [4] https://github.com/BaseXdb/basex/tree/issue873

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multi-threaded XQueries
by Ying Shanshan 23 Mar '14

23 Mar '14

Hi All, I created one database of 1GB in size, and have a batch of *read-only*queries to be performed. Each query is quite simple, so there is not much room to improve. All the queries are executed through *XQJ api.* If these queries are sequentially executed, it costs 5~8 seconds per query. To speed it up, I tried to executed it in a multi-thread way. But turns out to be much slower than the sequential one. This is what I wrote for each thread: public void run() { try { XQConnection conn = ds.getConnection(); XQSequence rs = conn.prepareExpression(input) .executeQuery(); //process the query result conn.close(); } } catch (Throwable e) { e.printStackTrace(); } } Anyone has the idea on how to improve the batch of queries. Thanks, -- Regards Shanshan School of Computing National University of Singapore

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Confusing error using GROUP BY
by Charles Duffy 23 Mar '14

23 Mar '14

Howdy -- I've run into a somewhat confusing error message using GROUP BY in BaseX 7.8.1, while trying to answer a question on StackOverflow ( http://stackoverflow.com/questions/22585865/grouping-with-counts-in-xquery) Against the database at http://www.ibiblio.org/xml/examples/shakespeare/hamlet.xml, I'm running the following query: for $line in //SPEECH/LINE let $speaker := $line/../SPEAKER/text()[1] group by $speaker return <speaker name="{$speaker}" count="{count($line)}"/> ...and receiving the error: [XPTY0004] Single item expected, (db:open-pre("hamlet",748), db:open-pre("hamlet",750)) found. I've gone over the GROUP BY docs several times, and not seeing my error in the above. Could someone enlighten?

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Re: [basex-talk] pearl pigments
by tony-zhao＠vip.188.com 22 Mar '14

22 Mar '14

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Traling empty nodes in csv:serialize
by Lars Johnsen 22 Mar '14

22 Mar '14

Hi all I have a question about csv:serialize and blank nodes. Trailing blanks are indicated with a separator, but those in the middle are. csv:serialize( <rows> <row> <f>1</f> <s>2</s> <t>3</t></row> <row> <f></f> <s></s> <t>3</t></row> <row> <f>1</f> <s></s> <t>3</t></row> <row> <f>1</f> <s></s> <t></t></row> <row> <f>1</f> <s>2</s> <t></t></row> </rows>) Here is the output (BaseX 7.8.1) , where line 4 and 5 are missing trailing separators: 1,2,3 ,,3 1,,3 1 1,2 Could this be fixed, or is it a feature? All the best Lars G Johnsen National Library of Norway

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Re: [basex-talk] Bug (?) - trailing whitespace in text nodes
by Hans-Juergen Rennau 21 Mar '14

21 Mar '14

Mm, the documentation says: "Chops all leading and trailing whitespaces from text nodes while building a database, and discards empty text nodes. By default, this option is set to true, as it often reduces the database size by up to 50%. It can also be turned off on command line via -w." The text states clearly that chopping affects only text nodes stored into a database. At any rate - the problem remains, whether or not I use option -w, and whether or not I use prolog option db:chop. (Side remark: it would be a serious issue if the prolog option were required, as this would imply that standard conformant behaviour could only be achieved by making the code unportable.) Kind regards, Hans-Juergen -------------------------------------------- Dirk Kirsten <dk(a)basex.org> schrieb am Do, 20.3.2014: Betreff: Re: [basex-talk] Bug (?) - trailing whitespace in text nodes An: "Hans-Juergen Rennau" <hrennau(a)yahoo.de>, "basex-talk(a)mailman.uni-konstanz.de" <basex-talk(a)mailman.uni-konstanz.de> Datum: Donnerstag, 20. März, 2014 18:28 Uhr Dear Hans-Jürgen, I am not quite sure it is intended that the CHOP option is applied to text nodes. At least the wording in the documentation ("while building a database") does not indicate it, while I think it actually does make sense. Christian will have to answer whether this works as is intended behavior. However, you can set the chop option to false within your XQuery by declaring it declare option db:chop "false"; and this should also affect reading in files from the file system. At least this works for me. Cheers, Dirk On 20/03/14 17:47, Hans-Juergen Rennau wrote: > My understanding is that it only affects database documents, and I used file input. > > Nevertheless, I also tried option -w, but always got the same result. > > Kind regards, > Hans-Jürgen > > > > > > Hans-Juergen Rennau <hrennau(a)yahoo.de> schrieb am 17:45 Donnerstag, 20.März 2014: > > Dear Dirk, thank you. > > But this is strange - I ran the query using a file as input - not a database document. > > I tried two versions: > BaseX 7.8.2 beta f505185 [Standalone] > BaseX 8.0 beta 606f18b [Standalone] > > OS is Windows 7. > > I always get this result: > <para>xxx<emphasis role="italic">abc</emphasis>yyy.</para> > > Using a different XQuery processor, I get this result, as expected: > <para>xxx <emphasis role="italic">abc</emphasis> yyy.</para> > > Kind regards, > Hans-Jürgen > > > > > > Dirk Kirsten <dk(a)basex.org> schrieb am 17:10 Donnerstag, 20.März 2014: > > Dear Hans-Jürgen, > > When running local:edit() on an in-memory node I get the expected and > correct result, including whitespaces. > > I guess that you run this command on a database node and the XML > documents were parsed with CHOP being true (which is the default), this > would explain the behavior and would be as expected. If you do not want > this you might consider setting the CHOP option (see > https://docs.basex.org/wiki/Options#CHOP) to false. > > Cheers, > Dirk > > > On 20/03/14 16:57, Hans-Juergen Rennau wrote: >> Dear BaseX team, >> >> I think I observed a bug concerning trailing whitespace in text nodes. >> >> Please consider this input document: >> >> <para>xxx <emphasis role="italic">abc</emphasis> yyy.</para> >> >> >> [Note the blanks between xxx and <emphasis>.] >> >> The result of the following "null-transformation" >> >> ======================= >> >> declare function > local:edit($n as node()) >> as node()? { >> typeswitch($n) >> case document-node() return >> document {for $c in $n/node() return local:edit($c)} >> case element() return >> element {node-name($n)} >> {for $ac in $n/(@*, node()) return local:edit($ac)} >> default return $n >> }; >> local:edit(.) >> ======================= >> >> should be identical, but what I get is this: >> >> <para>xxx<emphasis role="italic">abc</emphasis>yyy.</para> >> >> The > blanks after "xxx" are gone! >> >> >> When transforming mixed content like docbook, this can have awkware consequences. >> >> Kind regards, >> Hans-Jürgen >> >> >> >> _______________________________________________ >> BaseX-Talk mailing list >> BaseX-Talk(a)mailman.uni-konstanz.de >> https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk >> > -- Dirk Kirsten, BaseX GmbH, http://basex.org |-- Firmensitz: Blarerstrasse 56, 78462 Konstanz |-- Registergericht Freiburg, HRB: 708285, Geschäftsführer: | Dr. Christian Grün, Dr. Alexander Holupirek, Michael Seiferle `-- Phone: 0049 7531 28 28 676, Fax: 0049 7531 20 05 22

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feature's requests and not publicly released features
by Fabrice Etanchaud 21 Mar '14

21 Mar '14

Dear all, First of all, BaseX is just fantastic ! Could you please tell me if you may release the following features in near future ? 1. User defined indexes Let's consider you have to index multi lingual documents. Currently, one have to partition each document in mono-lingual documents, and add them in separate collections because there can be only one fulltext index per collection, and because all text() nodes will be indexed. Are others BaseX users interested with user defined indexes (attribute, text, and fulltext) ? Wouldn't user defined indexes dramatically improve performance (during requests, and optimization) ? 2. Break current collection limitation on the maximum number of nodes. 3. Possibility to store millions of small documents, and do efficient 'db:replaces' or 'db:delete'. Last, How does BaseX team provide non-open-source features ? Best regards, Fabrice Etanchaud Questel/Orbit

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