: That was exactly it. I added the following line to schema.xml and it now works. : : <field name="_version_" type="long" indexed="true" stored="true"/>
Just to be clear: how exactly did you "upgraded to solr 4.0 from solr 3.5" -- did you throw out your old solrconfig.xml and use the example solrconfig.xml from 4.0, but keep your 3.5 schema.xml? Do you in fact have an <updateLog ... /> in your solrconfig.xml? (if so: then this is all known as part of SOLR-3432, and won't affect any users of 4.0-final -- but i want to be absolutely sure there isn't some other edge case of this bug) -Hoss
