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

27 May 2011


      I am having issue with "group by" operator.
If I use it within  another "group by", nested "group by" won't work as the
following. $propvals in nested "group by" won't include grouped values.
let $list := for $p in $prods//RECORD
                                let $cid := $p/PROP[@NAME eq
"SubCategoryId"]/PVAL
                                let $allprops := $p/PROPGROUP/PROP
                                let $propgprs := for $prop in $allprops
                                                                      let
$propname := $prop/@NAME
                                                                      let
$propvals := $prop/PVAL
                                                                      group
by $propname
                                                                      order
by $propname
return  <PROPVALS name="{$propname}">{$propvals}</PROPVALS>
group by $cid
                                order by $cid
                                return <CID cidid="{$cid}">{$propgprs}</CID>
Thanks
On Fri, May 13, 2011 at 9:08 AM, Erol Akarsu eakarsu@gmail.com wrote:
...
Is there a way Basex server can send us JSON output instead of xml?
Thanks
On Wed, May 11, 2011 at 10:28 AM, Erol Akarsu eakarsu@gmail.com wrote:
...
I am filtering one big xml db that 800Mb stored into basex db already.
When I write filtered data into a file, I am getting out of memory.
I know basex is generating result filtered document in memory before
writing and facing memory error.
Can basex write results block by block?
Thanks
On Wed, May 4, 2011 at 9:38 AM, Erol Akarsu eakarsu@gmail.com wrote:
...
I tried to delete some nodes with "delete nodes .." xquery update
command. It actually did what was requested.
I checked the database size that is still same as previous one. I know
the nodes deleted has a lot of data and I think database indexes would be
adjusted accordingly.
Then, I exported database as xml file and recreated db. I can see it has
real size.
My question is why DB is not adjusting indexes when nodes deleted?
Thanks
Erol Akarsu
On Fri, Apr 29, 2011 at 9:23 AM, Erol Akarsu eakarsu@gmail.com wrote:
...
Hi,
Have we thought on clustering basex servers so we can partition xml
documents?
Here, I am only interested in a global partitioning:
Let's say if we have xml document like this, I would like to partition
RECORDS content so that each host will have equal number of RECORD elements.
Then, we need to aggregate results of individual hosts.
Can we implement this simple clustering framework with Basex?
<RECORDS>
   <RECORD>
.....
  </RECORD>
<RECORD>
.....
  </RECORD>
</RECORDS>
On Mon, Apr 11, 2011 at 12:35 PM, Erol Akarsu eakarsu@gmail.comwrote:
...
Ok,
I was able to run full text search with another XML Database.
I am primarily interested in how Basex will play with big XML file
Wikipedia.
Actually, Database create of wikipedia is fine. But when I add full tet
search and indexes for it, it always throws out of memory exception error.
I have changed -Xmx with 6GB that is still not enough to generate
indexes for Wikipedia.
Can you help me on how to generate indexes with a machine that case
6GB for Basex process?
Thanks
Erol Akarsu
On Sun, Apr 10, 2011 at 4:07 AM, Andreas Weiler <
andreas.weiler@uni-konstanz.de> wrote:
...
Hi,
the following query could work for you:
declare namespace w="http://www.mediawiki.org/xml/export-0.5/";
for $i in doc("enwiki-latest-pages-articles")//w:sitename
return $i[. contains text "Wikipedia"]/..
-- Andreas
Am 09.04.2011 um 20:43 schrieb Erol Akarsu:
Hi
I am having difficulty in running full text operators. This script
gives siteinfo below
declare namespace w="http://www.mediawiki.org/xml/export-0.5/";
 let $d :=  fn:doc ("enwiki-latest-pages-articles")
return ($d//w:siteinfo)[1]
But  return $d//w:siteinfo[w:sitename contains text 'Wikipedia'] does
NOT give same node
Why "contains" ft operator behave incorrectly? I remember it was
working fine. I just dropped and recreated database and turn all indexes.
Can you help me?
Query info is here:
Query: declare namespace w="http://www.mediawiki.org/xml/export-0.5/
";
Compiling:

pre-evaluating fn:doc("enwiki-latest-pages-articles")
adding text() step
optimizing descendant-or-self step(s)
removing path with no index results
pre-evaluating (())[1]
binding static variable $res
pre-evaluating fn:doc("enwiki-latest-pages-articles")
binding static variable $d
adding text() step
optimizing descendant-or-self step(s)
removing path with no index results
simplifying flwor expression

Result: ()
Timing:

Parsing:  0.46 ms
Compiling:  0.42 ms
Evaluating:  0.17 ms
Printing:  0.1 ms
Total Time:  1.15 ms

Query plan:
<sequence size="0"/>
<siteinfo xmlns="http://www.mediawiki.org/xml/export-0.5/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <sitename>Wikipedia</sitename>
  <base>http://en.wikipedia.org/wiki/Main_Page</base>
  <generator>MediaWiki 1.17wmf1</generator>
  <case>first-letter</case>
  <namespaces>
    <namespace key="-2" case="first-letter">Media</namespace>
    <namespace key="-1" case="first-letter">Special</namespace>
    <namespace key="0" case="first-letter"/>
    <namespace key="1" case="first-letter">Talk</namespace>
    <namespace key="2" case="first-letter">User</namespace>
    <namespace key="3" case="first-letter">User talk</namespace>
    <namespace key="4" case="first-letter">Wikipedia</namespace>
    <namespace key="5" case="first-letter">Wikipedia talk</namespace>
    <namespace key="6" case="first-letter">File</namespace>
    <namespace key="7" case="first-letter">File talk</namespace>
    <namespace key="8" case="first-letter">MediaWiki</namespace>
    <namespace key="9" case="first-letter">MediaWiki talk</namespace>
    <namespace key="10" case="first-letter">Template</namespace>
    <namespace key="11" case="first-letter">Template talk</namespace>
    <namespace key="12" case="first-letter">Help</namespace>
    <namespace key="13" case="first-letter">Help talk</namespace>
    <namespace key="14" case="first-letter">Category</namespace>
    <namespace key="15" case="first-letter">Category talk</namespace>
    <namespace key="100" case="first-letter">Portal</namespace>
    <namespace key="101" case="first-letter">Portal talk</namespace>
    <namespace key="108" case="first-letter">Book</namespace>
    <namespace key="109" case="first-letter">Book talk</namespace>
  </namespaces>
</siteinfo>
On Mon, Apr 4, 2011 at 7:31 AM, Erol Akarsu eakarsu@gmail.comwrote:
> I imported  wikipedia xml into basex and tried to search it.
>
> But searching it takes longer.
>
> I tried to search one element that is first child of whole document
> and it took 52 sec.
> I know the XML file is very big 31GB. How can I optimize the search?
>
> declare namespace w="http://www.mediawiki.org/xml/export-0.5/";
>
> let $d := fn:doc ("enwiki-latest-pages-articles")//w:siteinfo
> return $d
>
> Database info:
>
> > open enwiki-latest-pages-articles
> Database 'enwiki-latest-pages-articles' opened in 778.49 ms.
> > info database
> Database Properties
>  Name: enwiki-latest-pages-articles
>  Size: 23356 MB
>  Nodes: 228090153
>  Height: 6
>
> Database Creation
>  Path: /mnt/hgfs/C/tmp/enwiki-latest-pages-articles.xml
>  Time Stamp: 03.04.2011 12:29:15
>  Input Size: 30025 MB
>  Encoding: UTF-8
>  Documents: 1
>  Whitespace Chopping: ON
>  Entity Parsing: OFF
>
> Indexes
>  Up-to-date: true
>  Path Summary: ON
>  Text Index: ON
>  Attribute Index: ON
>  Full-Text Index: OFF
> >
>
>
> Timing info:
>
> Query: declare namespace w="http://www.mediawiki.org/xml/export-0.5/
> ";
> Compiling:
> - pre-evaluating fn:doc("enwiki-latest-pages-articles")
> - optimizing descendant-or-self step(s)
> - binding static variable $d
> - removing variable $d
> - simplifying flwor expression
> Result: element siteinfo { ... }
> Timing:
>  - Parsing:  1.4 ms
>  - Compiling:  52599.0 ms
>  - Evaluating:  0.28 ms
>  - Printing:  0.62 ms
>  - Total Time:  52601.32 ms
> Query plan:
> <DBNode name="enwiki-latest-pages-articles" pre="5"/>
>
>
>
> Result of query:
>
> <siteinfo xmlns="http://www.mediawiki.org/xml/export-0.5/"
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance%22%3E
>   <sitename>Wikipedia</sitename>
>   <base>http://en.wikipedia.org/wiki/Main_Page</base>
>   <generator>MediaWiki 1.17wmf1</generator>
>   <case>first-letter</case>
>   <namespaces>
>     <namespace key="-2" case="first-letter">Media</namespace>
>     <namespace key="-1" case="first-letter">Special</namespace>
>     <namespace key="0" case="first-letter"/>
>     <namespace key="1" case="first-letter">Talk</namespace>
>     <namespace key="2" case="first-letter">User</namespace>
>     <namespace key="3" case="first-letter">User talk</namespace>
>     <namespace key="4" case="first-letter">Wikipedia</namespace>
>     <namespace key="5" case="first-letter">Wikipedia talk</namespace>
>     <namespace key="6" case="first-letter">File</namespace>
>     <namespace key="7" case="first-letter">File talk</namespace>
>     <namespace key="8" case="first-letter">MediaWiki</namespace>
>     <namespace key="9" case="first-letter">MediaWiki talk</namespace>
>     <namespace key="10" case="first-letter">Template</namespace>
>     <namespace key="11" case="first-letter">Template talk</namespace>
>     <namespace key="12" case="first-letter">Help</namespace>
>     <namespace key="13" case="first-letter">Help talk</namespace>
>     <namespace key="14" case="first-letter">Category</namespace>
>     <namespace key="15" case="first-letter">Category talk</namespace>
>     <namespace key="100" case="first-letter">Portal</namespace>
>     <namespace key="101" case="first-letter">Portal talk</namespace>
>     <namespace key="108" case="first-letter">Book</namespace>
>     <namespace key="109" case="first-letter">Book talk</namespace>
>   </namespaces>
> </siteinfo>
>
>
>
> Thanks
>
> Erol Akarsu
>
>
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