Most simple way (URL?) to trigger SOLR commit of all pending docs?

THIS HOLDS FOR SOLR VERSIONS < 5.0

Try [solr url]/update?commit=true

For example, with an URL like the SOLR example defaults, from the same machine, http://localhost:8983/solr/update?commit=true should do it.

FOR SOLR VERSIONS >= 5.0
http://localhost:8983/solr/[collection_name]/update?commit=true