alex, thank you for the link.
i enabled the trace for 'org.apache.solr.handler.dataimport' and it
seems as if the database is only called once:
2013-03-21T09:40:43
1363855243889
50
org.apache.solr.handler.dataimport.JdbcDataSource
FINE
org.apache.solr.handler.dataimport.JdbcDataSou
There was something like this on Stack Overflow:
http://stackoverflow.com/questions/15164166/solr-filelistentityprocessor-is-executing-sub-entities-multiple-times
Upgrading Solr helped partially, but the conclusion was not fully
satisfactory.
Regards,
Alex.
Personal blog: http://blog.outerth