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

limit on number of attributes
by C. M. Sperberg-McQueen 10 Mar '11

10 Mar '11

Trying to use BaseX to index the XML version of the Unicode Database, I got a message saying an element had been encountered with too many attributes (more than 32). Is there a way to lift this limit for a particular database? If one wants to work with the Unicode database in XML (and let's face it, it will be a lot nicer in XML than in the semicolon-delimited form of the early Unicode releases), then one is going to have to work with elements which have a lot of attributes (haven't counted, probably fewer than a hundred). -- C. M. Sperberg-McQueen **************************************************************** * C. M. Sperberg-McQueen, Black Mesa Technologies LLC * http://www.blackmesatech.com * http://cmsmcq.com/mib * http://balisage.net ****************************************************************

2 2

renaming a database
by Godmar Back 09 Mar '11

09 Mar '11

Last year [1], the functionality to rename a database was requested. We need this functionality as well. The option to rename the folder would require shutting down, and restarting, the BaseX server, which is not a good idea. The other alternative would be to retrieve the entire XML content of the source db, then create the target db with that content; this is wasteful and inefficient for large db. Please add a db rename functionality to the Java client binding. - Godmar [1] https://mailman.uni-konstanz.de/pipermail/basex-talk/2010-May/000298.html

4 5

Re: [basex-talk] How to delete a node with PHP?
by Christian Grün 08 Mar '11

08 Mar '11

Dear Yoann Maingon, your code snippet looks fine to me. I would assume that a third command won't return any results, as they should have been deleted from your database: print $session->execute(“XQUERY //definition/item[@type=’test’]”); If that's not the case, or if I didn't answer your question, feel free to give us more details on your problem. Christian On Tue, Mar 8, 2011 at 12:46 AM, Yoann Maingon <yoann.maingon(a)prodeos.com> wrote: > > Hi, > > I’ve started using BaseX as a database for a PHP project. I can open the database and add nodes but I can’t delete nodes. > I’ve tested the XQUERY on the GUI and it works just fine. Any clue? > > Here is the xquery: > > Here is the php code: > […] > $session->execute(“OPEN data”); > $session->execute(“XQUERY delete nodes (//definition/item[@type=’test’])”); > > I’ve tried without “XQUERY” but gives the same result. > > Would be nice to have a working example of such use. > > Best Regards, > Yoann Maingon > > --------------------------------------- > Yoann Maingon > Prodeos > +33 6.64.32.49.66 > yoann.maingon(a)prodeos.com > www.prodeos.com

2 1

How to delete a node with PHP?
by Yoann Maingon 08 Mar '11

08 Mar '11

Hi, I've started using BaseX as a database for a PHP project. I can open the database and add nodes but I can't delete nodes. I've tested the XQUERY on the GUI and it works just fine. Any clue? Here is the xquery: Here is the php code: [.] $session->execute("OPEN data"); $session->execute("XQUERY delete nodes (//definition/item[@type='test'])"); I've tried without "XQUERY" but gives the same result. Would be nice to have a working example of such use. Best Regards, Yoann Maingon --------------------------------------- Yoann Maingon Prodeos +33 6.64.32.49.66 <mailto:yoann.maingon@prodeos.com> yoann.maingon(a)prodeos.com LOGO_14032009_OnWhite_Signature www.prodeos.com

1 0

Problem with Wikipedia database (or a more general namespace efficiency problem?)
by NewIntellectual 01 Mar '11

01 Mar '11

As both a stress test and to experiment, I created a database using a recent complete (current page) dump of English Wikipedia, a hefty file of 30.5 GB. I don't have enough memory apparently to create a full-text index of all of that text, so I created the DB without one. My first testing came up empty until I realized that I needed to deal with the namespace (ugh). Then I tried: declare default element namespace "http://www.mediawiki.org/xml/export-0.4/ "; //siteinfo This contains a small amount of data and occurs only once in the document (at /mediawiki/siteinfo). However, it's extremely slow (~33 seconds on my system). The query plan is: <IterPath> <Root/> <IterStep axis="child" test="*:mediawiki"/> <IterStep axis="child" test="*:siteinfo"/> </IterPath> Timing: - Parsing: 0.35 ms - Compiling: 0.22 ms - Evaluating: 33316.32 ms - Printing: 0.3 ms - Total Time: 33317.19 ms My surmise is that millions of node names are being checked rather than a path index being used to rapidly access the appropriate node(s). I don't think such a simple query should fail to be properly optimized. Another surmise is that it's related to namespaces not being indexed (?). While personally I very much dislike namespaces, they are common, and they have to be efficiently handled. To see if it made a difference, I also tried an explicitly named namespace test: declare namespace w="http://www.mediawiki.org/xml/export-0.4/"; //w:siteinfo This results in: <IterPath> <Root/> <IterStep axis="descendant" test="w:siteinfo"/> </IterPath> Timing: - Parsing: 0.33 ms - Compiling: 0.07 ms - Evaluating: 54288.51 ms - Printing: 0.3 ms - Total Time: 54289.23 ms So performance is even worse.

4 11

EXPath ZIP Module
by Christian Grün 01 Mar '11

01 Mar '11

Dear all, BaseX now offers (slightly modified) support for the EXPath ZIP Module. This module allows everyone to extract files from ZIP archives, list its contents, create new archives, and update existing archives. As far as we know, our implementation is the first one which is simply usable out of the box, and may be the first complete implementation as well. The ZIP Module is included in our latest build, available at: http://files.basex.org/releases/latest/ Please have a look at our documentation to find more details and examples: http://docs.basex.org/wiki/ZIP_Functions All the best, Christian ___________________________ BaseX Christian Grün Uni KN, Box 188 78457 Konstanz, Germany http://www.inf.uni-konstanz.de/~gruen

1 0

FindBugs for BaseX
by Godmar Back 26 Feb '11

26 Feb '11

2011/2/26 Leonard Wörteler <leonard.woerteler(a)uni-konstanz.de>: > Hi Godmar, > > that bug was pretty easy to fix, and I have no idea how the superfluous > downcast passed all our tests. It was introduced in version 6.2.8. Generally, downcasts are bad software engineering practice and can and should be avoided or minimized by proper design. Either change the method signature to let the compiler flag attends at passing incompatible types, or add virtual methods to a superclass/interface, or (last resort) use instanceof. Findbugs is a tool that flags errors such as these; you may have heard of it. Running Findbugs over the current codebase yields 563 warnings, some of which are clear bugs. I recommend you do that. For example: void delete(final int pre, final int size) { NSNode nd = root.find(pre); if(nd.pre == pre) nd = nd.par; if(nd == null) root = rootDummy; while(!nd.equals(rootDummy)) { nd.delete(pre, size); nd = nd.par; } } if 'nd == null', 'nd.equals()' crashes. If it can't be null, then 'root = rootDummy' is bogus. Or: case GRANT: final CmdPerm perm = consume(CmdPerm.class, cmd); if(perm == null) help(null, cmd); final String db = key(ON, null) ? name(cmd) : null; key(TO, cmd); return db == null ? new Grant(perm, name(cmd)) : new Grant(perm, name(cmd), db); if 'perm' is null, you crash in the 'Grant' constructor when calling perm.toString(). If it can't be null, the check is bogus. Or: @Override public boolean uses(final Use u) { return u == Use.CTX && (def == FunDef.MB || def == FunDef.MB || def == FunDef.EVAL || def == FunDef.RUN) || super.uses(u); } Did you mean to check for two different values instead of FunDef.MB twice. Or: // [CG] XQuery/Formatter: calendars and places are ignored if(cal != null || plc != null); Did you mean to return if cal != null || plc != null rather than doing nothing? Or in FTWrods.java if(iat == null) { final FTLexer lex = new FTLexer(ftt.opt); /* elided */ if(iat == null) { iat = ia; tl = t; } else if(mode == FTMode.M_ALL || mode == FTMode.M_ALLWORDS) { iat = FTIndexIterator.intersect(ia, iat, 0); tl += t; } else { iat = FTIndexIterator.union(ia, iat); tl = Math.max(t, tl); } iat.tokenNum(++ctx.ftoknum); } return iat.more() ? new FTNode(iat.matches(), data, iat.next(), tl, iat.indexSize(), iat.score()) : null; } The code in the else branch is dead - iat is always null where you test it due to the dominating test on entry. The 'intersect' and 'union' call is never made. Etc. well worth the time fixing. - Godmar

2 1

Options to generate JSON file
by Jan Vlčinský (CAD) 26 Feb '11

26 Feb '11

Hi I shall export JSON file based on XML structures I have in my XQuery. Here I found http://demo.exist-db.org/xquery/json-test.xql/source sample, how eXistDB can produce JSON data. It is like import module namespace json="http://www.json.org"; 04. 05.declare option exist:serialize "method=xhtml media-type=text/html"; let $xml1 := 08.<root> 09.<h1>H</h1> 10.<p/> 11.<p>some text</p> 12.<h2>HH</h2> 13.</root> <script type="text/javascript"> 43.var data1 = {json:xml-to-json($xml1)}; BaseX does not provide this and I wonder, what options I have and what would anyone recommend 1. building up plain text piece by piece by XQuery 2. using some Java lib for this (there are more, any practical experience welcome) 3. Some other trick, which lives hidden to me (I already queried BaseX wiki and no hit) Jan -- *Ing. Jan Vlčinský* CAD programy Slunečnicová 338/3, 734 01 Karviná Ráj, Czech Republic tel: +420-597 602 024; mob: +420-608 979 040 skype: janvlcinsky; GoogleTalk: jan.vlcinsky(a)gmail.com http://cz.linkedin.com/in/vlcinsky

3 3

Server Crash
by Sony Vijay 26 Feb '11

26 Feb '11

Hi, I am using BaseX 6.5. I am running into a server crash. Could you fix it ? I see the following error where I run my server: Exception in thread "Thread-4" java.lang.NullPointerException at org.basex.query.up.Updates.size(Updates.java:110) at org.basex.query.QueryProcessor.updates(QueryProcessor.java:234) at org.basex.server.QueryProcess.initInfo(QueryProcess.java:162) at org.basex.server.QueryProcess.close(QueryProcess.java:139) at org.basex.server.ServerProcess.query(ServerProcess.java:291) at org.basex.server.ServerProcess.run(ServerProcess.java:128) Also, please find attached a copy of the complete log file. Thanks, Sony

5 7

Re: [basex-talk] BaseX question - Enhancing JAX-RX interface
by Jan Vlčinský (CAD) 26 Feb '11

26 Feb '11

Hi Christian I did try to write my ideas, but landed at reading what is REST and what not - and run out of time. So here is draft of some of ideas - unfortunately without clear proposal for next action, but someone will probably take it over and move on. Jan JAX-RX and BaseX - Aim - Summarize ideas and requests regarding JAX-RX interface of BaseX database - Topics - Mixing commands and queries in one request - Get and relevant post implementation without breaking compatibility - Are we REST like and do we need it? - What processing context we need - Typical Use Cases - Add document(s) and optimize - why - Want to be sure, that indexes will be updated after collection has been modified and no one will have a chance to run a query on not optimized collection - Updating query and optimize - why - Want to be sure, that indexes will be updated after collection has been modified and no one will have a chance to run a query on not optimized collection - Query with client defined timeout - why - It is better to quit too long query then risking that one too expensive query would endanger overall server performance There is no need to get query results too late, when our http connection already timed out - Set of independent simple expression queries - Mix updating and simple expression queries - Set of independent commands - why - Needing to run a batch of tasks, which cannot be interrupted by other clients - Ideas - add timeout parameter to each request - check, what other timeout-like parameters we may need - introduce new request element for POST, mixing queries and commands - Possible problems - compatibility with existing design - wish to pass query result into next command/query 2011/2/24 Christian Grün <christian.gruen(a)gmail.com> > > OK, I understand, that REST allows to perform the (SET) command, but to > use > > it with a query, I have to send the query in another, following, request. > > Will this second request keep enough context at the server side to know, > it > > shall use that timeout? > > Just recently, I've thought about extending the JAX-RX Interface to > allow more than a single query or command, or to allow both commands > and queries; regarding the syntax, this could be easily realized for > the GET method: > > http://localhost:8984/basex/jax-rx/factbook?query=1&query=2 > > http://localhost:8984/basex/jax-rx/factbook?command=set+timeout+1&query=1&c… > > On the other hand, I haven't decided yet how to best realize it for > the POST method without giving up compatibility. One solution could be > to introduce alternative "request" root elements: > > <request xmlns="http://jax-rx.sourceforge.net"> > <command> > <text>set timeout 1</text> > </command> > <query> > <text>//name</text> > <parameter name="count" value="5"/> > </query> > </request> > > What does everyone think? > Christian > _______________________________________________ > BaseX-Talk mailing list > BaseX-Talk(a)mailman.uni-konstanz.de > https://mailman.uni-konstanz.de/mailman/listinfo/basex-talk > -- *Ing. Jan Vlčinský* CAD programy Slunečnicová 338/3, 734 01 Karviná Ráj, Czech Republic tel: +420-597 602 024; mob: +420-608 979 040 skype: janvlcinsky; GoogleTalk: jan.vlcinsky(a)gmail.com http://cz.linkedin.com/in/vlcinsky

2 6