BaseX-Talk December 2021

basex-talk@mailman.uni-konstanz.de

20 participants
26 discussions

BaseX 9.6: The Summer Edition
by Christian Grün 28 Nov '24

28 Nov '24

Dear all, We provide you with a new and fresh version of BaseX, our open source XML framework, database system and XQuery 3.1 processor: https://basex.org/ Apart from our main focus (query rewritings and optimizations), we have added the following enhancements: XQUERY: MODULES, FEATURES - Archive Module, archive:write: stream large archives to file - SQL Module: support for more SQL types - Full-Text Module, ft:thesaurus: perform Thesaurus queries - Fulltext, fuzzy search: specify … [View More]

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recursively used variables
by Rob Stapper 12 Aug '24

12 Aug '24

Hi, The code[1] below and send as attachment generates a error message: “Static variable depends on itself: $Q{http://www.w3.org/2005/xquery-local-functions}test”. I use these variables to refer to my private functions in my modules so I can easyly refer to them in a inheritance situation. It’s not a big problem for me but I was wondering if the error-triggering is justified or that it should work. [1]=========================================== declare variable $local:test := local:test#1 ; … [View More]

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User group meeting in Prague?
by Imsieke, Gerrit, le-tex 10 Apr '22

10 Apr '22

Fellow BaseX Users! You might have heard that XML Prague 2022 will take place in June. (Unless the then-prevalent Greek letter makes it impossible even in that time of year, of course.) I asked Christian whether the BaseX team will organize a user group meeting after it had not happened for years now. Christian didn’t seem to be very fond of organizing such a meeting. I asked him whether he would be available to present new features, the roadmap, and for a Q&A session if the users … [View More]

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Questions about the performance of bulk string matching
by Zimmel, Daniel 18 Jan '22

18 Jan '22

Hi, recently I ran into serious (as in SERIOUS) performance trouble regarding expensive regexes, and no wonder why. Here is my scenario: * XML text documents with a total of 1m text nodes * A regex search string, including a huge string dictionary list of 50.000 strings (some of them containing 50 words each) * a match must be wrapped in an element (= create a link) I could drink many cups of tea while waiting for the regex to complete... hours... I ran out of tea! Then I found the 2021 … [View More]Balisage paper from Mary Holstege titled "Fast Bulk String Matching" [1] in which she explores the Aho-Corasick algorithm, implementing it with XQuery - marvellous! Following this, while I can build a data structure which gives me fast results, building the same structure is still very slow due to the amount of text to build from. So this was not fast enough for my use case - or I may simply not be smart enough to apply it correctly :-| So, I tried tinkering with maps which turned out to give me extraordinary performance gains: * build a map from the string dictionary * walk through all text nodes one by one * for each text node, put any combination of words in the text node in word order (I need to find strings, not words) into another map * strip punctuation (for word boundaries) and do some normalization of whitespaces in both maps * compare the keys of both maps * give the new reduced string dictionary to the regular regex search While comparing the maps, I do not know where in the text my strings are, but at least I know if they are in there - to find out where exactly (and how do they fit my other regex context) I can then use a massively reduced regular regex search. Fast! I am quite happy BUT I still cannot understand why this is so much faster for my sample data: * plain method : 51323.72ms * maps method: 597.94ms(!) Is this due to any optimizations done by BaseX or have I simply discovered the power of maps? How would you do it? Is there still room for improvement? Why does Aho-Corasick not help much with this scenario? Is it because the list of strings is simply too massive? Why is this so much faster with text-splitting-to-map? See below for the query examples to better understand what I am trying to do (bulk data not included) [2],[3] There is no normalization of punctuation in the examples but that is only necessary for completeness. Best, Daniel [1] http://www.balisage.net/Proceedings/vol26/print/Holstege01/BalisageVol26-Ho… [2] plain method let $textnodes := fetch:xml(file:base-dir()||file:dir-separator()||'example.xml')//text() let $strings := file:read-text(file:base-dir()||file:dir-separator()||'strings.txt') let $regex := $strings for $textnode in $textnodes where matches($textnode,$regex) = true() return $textnode [3] maps method (:~ : Create map from string : Tokenization : : @param $strings : @return Map :) declare function local:createMapFromString ( $string as xs:string ) as map(*) { let $map_words := map:merge( for $string in tokenize($string,'\|') let $key := $string let $val := $string return map:entry($key,$val), map { 'duplicates': 'use-first' }) return $map_words }; (:~ : Create map from text nodes : Write any combination of words in document order to the map : : @param $textnodes : @return Map :) declare function local:createMapFromTextnodes ( $textnodes as xs:string+ ) as map(*) { map:merge( for $node in $textnodes let $text := normalize-space($node) let $tokens := tokenize($text,' ') let $map_nodes := map:merge( for $start in 1 to fn:count($tokens) for $length in 1 to fn:count($tokens) - $start + 1 return map:entry(fn:string-join(fn:subsequence($tokens, $start, $length), ' '),'x') ) return $map_nodes) }; (:~ : Compare two maps : : @param $map1 : @param $map2 : @return xs:string* :) declare function local:reduceMaps ( $map1 as map(*), $map2 as map(*) ) as xs:string* { for $key in map:keys($map1) where map:contains($map2,$key) let $value := map:get($map1,$key) return $value }; let $textnodes := fetch:xml(file:base-dir()||file:dir-separator()||'example.xml')//text() let $strings := file:read-text(file:base-dir()||file:dir-separator()||'strings.txt') let $map_words := local:createMapFromString($strings) let $map_textnodes := local:createMapFromTextnodes($textnodes) let $matches := local:reduceMaps($map_words,$map_textnodes) let $regex := string-join(for $match in $matches group by $match return $match,'|') for $textnode in $textnodes where matches($textnode,$regex) = true() return $textnode [View Less]

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9.6 on Docker Hub
by Johannes Bauer 10 Jan '22

10 Jan '22

Hi, I cannot find the latest BaseX release on Docker Hub (only the 9.5 branch). Is this still planned? Thank you. Best Regards Johannes

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Re: [basex-talk] Copy data from MariaDB into BaseX
by Christian Grün 23 Dec '21

23 Dec '21

Thanks. Does the query do what you are looking for? On Tue, Dec 21, 2021 at 12:47 PM <benengbers(a)dds.nl> wrote: > > Christian Grün schreef op 21-12-2021 10:18: > > Hi Ben, > > > return db:add($db, $doc, $table || '.xml') > > > > Could you give us little examples for <DB-name>, <DB-schema> and > > <table-name> ? > > > > Best, > > Christian > > To the best of my knowledge in MySQL and/or MariaDB DB-name and … [View More]

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Copy data from MariaDB into BaseX
by Ben Engbers 21 Dec '21

21 Dec '21

Hi, After completing my work on the R-client, I started working on a Prolog-client. Long ago I wrote an application in SWI-Prolog which operated on data from a MySQL-database. (In the meantime I changed from MySQL to MariaDb). My goal is to write a new version of that application but now based on data which is stored in Basex. In the basexgui, I created an empty database "MariaBases" The following code can be used to select data in MariaDb: sql:init("org.mariadb.jdbc.Driver"), let $con :=… [View More]

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BaseX 9.6.4: Tweaks, Fixes & Thank Yous
by Christian Grün 17 Dec '21

17 Dec '21

Dear all, We conclude this year with yet another release of BaseX, our XML framework, database and XQuery processor [1]. The new version contains new performance tweaks and minor bug fixes, the details of which can be examined on our GitHub page [2]. As we’ve got numerous inquiries regarding Log4j: I can comfort you that BaseX is not affected by the vulnerabilities. We have our own logging mechanism, which has no built-in code execution features. The same applies to the Jetty web server. … [View More]

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Email.jar module documentation
by Eliúd Santiago Meza y Rivera 16 Dec '21

16 Dec '21

Hi, Sorry for ask, but where I can find or read more about email.jar module documentation?, I'm working for a personal project and beside to send e-mail, I need to read some emails, or is there another options to do this task. Cheers. Eliud Meza

2 1

Log4j vulnerability CVE-2021-44228
by Marc Coenegracht 13 Dec '21

13 Dec '21

Does Basex (9.x or 8.x) use Log4j in any of its components? If not, should one still worry about the JRE? Regards, Marc

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BaseX-Talk December 2021