Failure of conditional combination index in eXist-db range index - exist-db

Question

I encountered the following problems in eXist-db configuring range indexes to specify attributes that are worth indexing.
<collection xmlns="http://exist-db.org/collection-config/1.0" xmlns:xs="http://www.w3.org/2001/XMLSchema">
<index>
<range>
<create qname="tei:term">
<condition attribute="type" value="main"/>
<field name="mainTerm" type="xs:string"/>
</create>
</range>
</index></collection>
Error occurred:"/db/system/config/db/range/collection.xconf cvc-complex-type.2.4.a: Invalid content was found starting with element 'condition'. One of '{"http://exist-db.org/collection-config/1.0":field}' is expected."
Please help me.

Answer 1

The error you are getting is a schema validation error, triggered by the presence of the <condition> element used by the recently introduced conditional combined index feature.
I've submitted a fix to the error, and for now, you can ignore the error. The schema validation error will not have any effect on the functionality.

Answer 2

General Configuration Structure and Syntax
Index configuration collection.xconf files are standard XML documents that have their elements and attributes defined by the eXist-db namespace http://exist-db.org/collection-config/1.0. The following example shows a configuration example:
<collection xmlns="http://exist-db.org/collection-config/1.0">
<index>
<!-- Full text index based on Lucene -->
<lucene>
<text qname="SPEECH">
<ignore qname="SPEAKER"/>
</text>
<text qname="TITLE"/>
</lucene>
<!-- Range indexes -->
<range>
<create qname="title" type="xs:string"/>
<create qname="author" type="xs:string"/>
<create qname="year" type="xs:integer"/>
</range>
<!-- N-gram indexes -->
<ngram qname="author"/>
<ngram qname="title"/>
</index>
</collection>
To use the new range index, wrap the range index definitions into a range element:
<collection xmlns="http://exist-db.org/collection-config/1.0">
<!--from Tamboti-->
<index xmlns:mods="http://www.loc.gov/mods/v3">
<lucene>
<text qname="mods:title"/>
</lucene>
<!-- Range indexes -->
<range>
<create qname="mods:namePart" type="xs:string" case="no"/>
<create qname="mods:dateIssued" type="xs:string"/>
<create qname="#ID" type="xs:string"/>
</range>
</index>
</collection>
Conditional combined indexes
For combined indexes, you can specify conditions to restrict the values being indexed to those contained in elements that have an attribute meeting certain criteria:
<range>
<create qname="tei:term">
<condition attribute="type" value="main"/>
<field name="mainTerm" type="xs:string"/>
</create>
</range>
This will only index the value of the tei:term element if it has an attribute named type with the value main. Multiple conditions can be specified in an index definition, in which case all conditions need to match in order for the value to be indexed.
Make sure you have a valid xml. For further details, you can read the documentation here: https://exist-db.org/exist/apps/doc/newrangeindex.xml