BaseX-Talk

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1 participants
5252 discussions

concurrent performance issues?
by Michael Perkonigg 08 Apr '19

08 Apr '19

Hallo, ich versuche gerade, BaseX hier für eine zentrale XML-DB zu evaluieren. Die DB ist read-only. Wir haben also keinerlei Updates. Wir haben verschiedene XQuery-Queries(?), die abgesetzt werden, dabei ist aufgefallen, dass wenn ich mehrere Queries parallel starte die Antwortzeiten unverhätnismässig steigen. Einzeln: Query1: 500ms Query2: 1200ms Parallel brauchen beide zusammen dann zwischen 3 und 5 Sekunden. Erstaunlicherweise sind die Antwortzeiten mit der Option PARALLEL=1 am geringsten, d.h. bei der Defaulteinstellung PARALLEL=8 (und auch schon bei PARALLEL=2) steigen die Antwortzeiten. Ich frage mich nun, ob BaseX als Datenbank für eine verteilte Applikation mit zentraler DB überhaupt geeignet ist und ob ich vielleicht mit irgendwelchen Optionen BaseX für meine Zwecke optimieren kann. Ganz theoretisch könnte die DB ja mit hundert parallelen Anfragen belastet werden. -- mit freundlichen Grüßen

3 2

Two questions on use of the serialize function and character maps
by Martin Honnen 08 Apr '19

08 Apr '19

I am struggling to use the "serialize" XPath 3.1 function as specified by the W3C with BaseX 9.1.2: 1) Is there any way to provide the "use-character-maps" parameter supplied the XPath 3.1 way with a second argument to "serialize" as a map: serialize("a,b", map { 'method' : 'text', 'use-character-maps' : map { "'" : "&apos;" }}) I get an error saying [SEPM0017] Invalid 'use-character-maps' value 'map { "'": "&apos;" }'; must be a string. 2) When I try the XPath 3.0 way of providing the serialization parameters as an XML element I also get an error: When I run declare namespace output = "http://www.w3.org/2010/xslt-xquery-serialization"; declare option output:method "text"; serialize( ( <text>'</text>, "'", map { "Ä":"\'C4", "Ö":"\'D6", "Ü":"\'DC", "ß":"\'DF", "ä":"\'E4", "ö":"\'F6", "ü":"\'FC" } ), <output:serialization-parameters xmlns:output="http://www.w3.org/2010/xslt-xquery-serialization"> <output:method value="adaptive"/> <output:use-character-maps> <output:character-map character="'" map-string="&apos;"/> </output:use-character-maps> </output:serialization-parameters> ) in BaseX it tells me [SEPM0017] Character map 'character-map=,' is not defined. Saxon 9.9 and Altova 2018 run that example without giving an error (although not with the same serialization result, but that is a different issue).

2 7

BigInteger
by Andre Bovy 05 Apr '19

05 Apr '19

Hi Chistian, I am trying to use a very Big Integer in BaseX (9.1.2) With this value : declare namespace BigInteger = "java:java.math.BigInteger"; BigInteger:new("12345678901234567890”) I received : Cannot convert xs:string to xs:integer: "12345678901234567890”. The java method that I used returns a BigInteger, but I just need the value as a String. I tried : BigInteger:toString(BigInteger:new("12345678901234567890”)) without success (same error) Is there a workaround to this behaviour ? without writing a Java class. Thank you in advance André

3 5

jobs:eval as a service, "no variables allowed"
by Zimmel, Daniel 03 Apr '19

03 Apr '19

Hi, when I try to register jobs:eval as a service, BaseX 9.2 says: "no variables allowed". Is it not possible to register a service with a variable? Not working: jobs:eval("declare variable $xml external; $xml", map { 'xml': 'XML' }, map { 'id':'TEST', 'start':'11:31:50', 'interval':'P1D', 'service': true() }) working: jobs:eval("declare variable $xml external; $xml", map { 'xml': 'XML' }, map { 'id':'TEST', 'start':'11:31:50', 'interval':'P1D', 'service': false() }) http://docs.basex.org/wiki/Jobs_Module#jobs:eval Thanks, Daniel

2 2

Tumbling window
by Giuseppe G. A. Celano 03 Apr '19

03 Apr '19

I have written the following code: for tumbling window $s in ("this", "is", "an", "example", "." , "this", "is", "another", "[", "example", ".", "]", "Another", "example", ".") start $a when fn:true() end $b next $r when ($b = "." and $r = "]") or $b = "." return <s>{$s}</s> which returns: <s>this is an example .</s> <s>this is another [ example .</s> <s>] Another example .</s> but I am looking for <s>this is an example .</s> <s>this is another [ example . ]</s> <s>Another example .</s> I am playing around with if-clauses, but I am wondering whether there is a more direct way to force the end of a sentence at "]" when it is preceded by "." or at "." when there is no following "]". Thanks. Ciao, Giuseppe

2 2

Hitting the Tail Recursion wall
by Andreas Mixich 02 Apr '19

02 Apr '19

Hi, I am trying to implement the algorithm outlined at https://tools.ietf.org/html/rfc3986#section-5.2.4 (Two other implementations are at [1] and [2]) The following function is my work in progress. It seems, all goes fine, till the last `else`, which is commented with `(: E :)`. I hit the tail recursion barrier and I do not see why. The function may not (yet) make sense, since I am still experimenting. `local:remove-dot-segments("/a/b/c/./../../g",[])` ``` (:~ Remove dot segments from a URI path component according to RFC 3986 Section 5.2.4 @param $path the path component of an URL @param $out an empty (!) array @return the path component with the relative part (dot segments) removed and resolved to the absolute path. @see https://tools.ietf.org/html/rfc3986#section-5.2.4 :) declare function local:remove-dot-segments( $path as xs:string, $out as array(*)) as item()* { concat("in: ", $path, " out: ", string-join(array:flatten($out))), if (not(contains($path, "."))) then $path else if (string-length($path) > 0) then (: A :) if (substring($path,1,3) = "../") then local:remove-dot-segments(substring($path, 4), $out) else if (substring($path, 1, 2) = "./") then local:remove-dot-segments(substring($path, 3), $out) else (: B :) if (substring($path,1,3) = "/./") then local:remove-dot-segments(concat("/", substring($path, 4)), $out) else if (substring($path, 1, 2) = "/.") then local:remove-dot-segments(concat("/", substring($path, 3)), $out) else (: C :) if (substring($path, 1, 4) = "/../") then let $ret := array:remove($out, array:size($out)) return local:remove-dot-segments(concat("/", substring($path, 5)), $ret) else if (substring($path, 1, 3) = "/..") then let $ret := array:remove($out, array:size($out)) return local:remove-dot-segments(concat("/", substring($path, 4)), $ret) else (: D :) if ($path = ".." or $path = ".") then local:remove-dot-segments(concat(substring((), 4), ""), $out) else (: E :) let $ret := if (starts-with($path, "/")) then array:append($out, concat("/", substring-before(substring($path,2), "/"))) else array:append($out, substring-before(substring($path,1), "/")) return local:remove-dot-segments($path, $ret) else $path }; ``` Sorry for throwing such a big function at you, but I do not find the place, where the stack overflow gets triggered. It does not happen, if I return an empty sequence at `else (: E :)`. If I replace that part (after `else (: E :)`) with `local:remove-dot-segments($path, $out)` I get the stack overflow as well, which is, what confuses me the most. [1]https://github.com/ariutta/remove-dot-segments/blob/master/index.js [2] https://gist.github.com/rdlowrey/5f56cc540099de9d5006 -- Goody Bye, Minden jót, Mit freundlichen Grüßen, Andreas Mixich

2 4

Using local xqj
by Gardner, Arthur 01 Apr '19

01 Apr '19

Hi! I've downloaded BaseX 9.2 (Windows distro). One thing I want to try is the xqj implementation, running locally on the server. I found the class net.xqj.basex.local.BaseXXQDataSource But when I try getConnection() on an instance of this, I get the following: java.lang.NoClassDefFoundError: org/basex/core/Proc I've searched for this class, but without success. Any ideas out there? Arthur Gardner | Infosys Ltd MetLife | Clarks Summit, PA Office 570-587-6898 | Mobile 262-442-7472 The information contained in this message may be CONFIDENTIAL and is for the intended addressee only. Any unauthorized use, dissemination of the information, or copying of this message is prohibited. If you are not the intended addressee, please notify the sender immediately and delete this message.

2 2

Quick Windows issue: Invalid reply on port 1984, works fine on port 8984
by Jim Salmons 01 Apr '19

01 Apr '19

Hello BaseX folk, I have just installed version 9.1.2 and am starting to learn BaseX in support of my post-cancer #PayItForward Bonus Round #CitizenScientist research in #DigitalHumanities and #MachineLearning. My goal is to "cut out the middleman" of writing intermediate JSON and XML fragment files in order to update the #MAGAZINEgts ground-truth storage file that I am developing for a digital collection of Softalk Apple magazine at the Internet Archive. With BaseX and its Python interface, I want to write new and updated document structure and content depiction metadata directly to a local copy of this ground-truth master file which will then be easily popped out of the database as an XML file for uploading to the Softalk Apple collection at the Internet Archive. I hit a bump, reported to the Github Issue queue, where my Windows 10 installation can not open the BaseX GUI exe launcher. The work-around, as noted in my issue report, is to use the Getting Started advice to execute the jar directly. By creating a desktop icon that launches the execuable jar in the installation folder, the GUI launches as expected. With that minor issue behind me, I am wondering why my attempts to connect to the server via localhost:1984 port does not work while everything is fine and dandy when hitting port 8984. Port 1984 returns an invalid HTTP response. (Note: Other ports that are not assigned to anything else return a connection refused, so this invalid response is not the same as the server not being there.) If I keep a Powershell window open with the server running, every once in a while (after several minutes or more) the server throws this error: java.lang.NullPointerException at org.basex.core.Context.perm(Context.java:252) at org.basex.core.Command.run(Command.java:250) at org.basex.core.Command.run(Command.java:143) at org.basex.core.cmd.Close.close(Close.java:54) at org.basex.server.ClientListener.close(ClientListener.java:232) at org.basex.BaseXServer$1.run(BaseXServer.java:157) at java.base/java.util.TimerThread.mainLoop(Timer.java:556) at java.base/java.util.TimerThread.run(Timer.java:506) which may be related to port 1984 not responding, a firewall issue perhaps? Honestly, I don't see anything that looks like a BaseX process or service running in Task Manager (other than a generic 'Java(TM) Platform SE binary' process, and there is nothing that looks related in the Windows Firewall entries. I'm still investigating this here, but if anyone knows what is akimbo, I would greatly appreciate your advice. Thank you... and looking forward to being a new BaseX community member. :-) Happy-Healthy Vibes, -: Jim Salmons :- Jim Salmons Twitter: @Jim_Salmons https://www.researchgate.net/profile/Jim_Salmons (my #CitizenScientist profile) www.medium.com/@Jim_Salmons/ (my mostly #DigitalHumanities writing)

3 4

Access variable database without locking all databases
by Leah Chatkeonopadol 29 Mar '19

29 Mar '19

Hi, I'm using BaseX as a database for a web application with RESTXQ API endpoints. Each endpoint has a database name specified as a path param, for example: declare %rest:GET %rest:path('data/{$database}/read') function readData($database as xs:string) { let $doc := fn:doc($database || '/data.xml') return $doc }; All of the queries inside the function are only run against a single database, but as described in the transaction management <http://docs.basex.org/wiki/Transaction_Management#Limitations> documentation, using fn:doc with a variable will lock all the databases. Is there any way around this? Any suggestions would be much appreciated. Thanks!

1 0

Higher order functions in XSLT
by nikos dimitrakas 28 Mar '19

28 Mar '19

Hi! Is there something in BaseX that prohibits using higher order functions in XSLT (called with xslt:transform)? for-each($somenodes, function($q) { string($q) }) and for-each($somenodes, string#1) both work in XQuery in BaseX, but when I use the same call in an XSLT that I call with xslt:transform, I get the following message XPST0003: Inline functions require support for higher-order-functions, which needs Saxon-PE or higher. I am using Saxon EE 9.9.1.2 (also tried PE 9.9.1.2) The XSLT works fine if I run it with Saxon directly without using BaseX and the function xslt:transform. Is there something I can do to get this to work, or is this out of my control? Regards /nikos

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