Hi Dimitar,

I have done the comparison between the function "contains" (without fulltext index) and "contains text" by using a 800 MB XML database. You can download the test data here: http://dl.dropbox.com/u/22427941/RootSearch.rar. 

1) Using a simple query:

+ declare default element namespace "http://iso.org/OTX";
for $pro in collection()//specification[text() contains text "Specification"]
return $pro

+ declare default element namespace "http://iso.org/OTX";
for $pro in collection()//specification[contains(text() ,"Specification")]
return $pro

The query with "contains text" ran a little bit faster than the query without full text index.

2) Using an complex query:

declare default element namespace "http://iso.org/OTX";

for $pro in collection()/otx/procedures/procedure
return for $hd in $pro/realisation/flow//handler
    where exists($hd/@*[contains(data(.),"Variable1")]) 
       or exists($hd/realisation/catch/exception//@*[contains(data(.),"Variable1")])
       or $hd/specification contains text "Specification" 
(:  or exists ($hd/specification[contains(data(.),"Specification")]   ):)
    return concat(data($pro/../../@package),":",data($pro/../../@name),":",data($pro/@name),":","handler",":",$hd/@id)

The variant with "contains text" ran much slower than the variant with "contains".

The indexes are used: path, text index, attribute index, full-text index (without any options)

Thanks for helping me.

Cheers,
An




On Fri, Nov 25, 2011 at 3:31 PM, Dimitar Popov <Dimitar.Popov@uni-konstanz.de> wrote:
Hi An,

Am Freitag, 25. November 2011, 11:30:00 schrieb Truong An Nguyen:
> Hi,
>
> I've two questions about the fulltext search.
>
> 1) I've created fulltext i for my  BaseX doesn't understand ftcontains.
> When I try a CONTAINS query in a 1 Gigabyte Database, using text index is
> slower than without text index. How can I use fulltext index rightly?

You can do several things:

1. Make sure that the full-text index is used, i.e. check the "query info" in
the GUI; it should contain "FTIndexAccess" similar to:

<FTIndexAccess data="factbook">
 <FTWords>
   <Item value="norway" type="xs:string"/>
 </FTWords>
</FTIndexAccess>

2a. If the full-text index is used, please send more details about your query
and data (e.g. what full-text options are used); it would be interesting to
see why the index query is slower.

2b. If the full-text index is NOT used, please check that the full-text
options you use in your query correspond to the options with which the full-
text index is created. For more information check our wiki page [1].

> 2) Does BaseX supports regular expression in the fulltext extension? If
> yes, could you please give me an example.

No, full blown regular expressions are not supported by XQuery Full-Text.
However, wild-cards are supported. For the correspond syntax and examples, you
can check the XQuery Full-Text specification [2].

> Thanks
>
> Cheers,
> An

Greetings,
Dimitar

[1] http://docs.basex.org/wiki/Full-Text
[2] http://www.w3.org/TR/xpath-full-text-10/#ftwildcardoption