FTS config - cannot search substrings

[Shawn Heisey]

On 11/18/2021 4:43 PM, infoomatic wrote:
> sometimes ignoring the problem for a few moments and then starting over
> again helps ...
> 
> the solution was already solved here in a mail over 10 years ago -
> https://dovecot.org/list/dovecot/2011-May/059338.html
> 
> Thanks Daniel Miller!

There's something to keep in mind here.  This is the critical piece that 
makes the substring search work:

<filter class="solr.NGramFilterFactory" minGramSize="3" maxGramSize="15"/>

Because the minimum size is 3, that config means that it is impossible 
to search for one or two letter words -- terms shorter than minGramSize 
are dropped.  This could affect the quality of search results.

If you are running at least version 7.4.0 of Solr, you can add this to 
the config for that filter so that isn't a problem:

preserveOriginal="true"

https://javadoc.io/static/org.apache.lucene/lucene-analyzers-common/7.4.0/org/apache/lucene/analysis/ngram/NGramFilterFactory.html

Thanks,
Shawn