How-to get date of indexing process

[Miguel]

Hi everybody

   I am looking for the way to get date of last indexing process or 
commit event that it happened in my Solr server.
I found a possible solution to add timestamp field , for example:
|<field name="timestamp"  type="date"  indexed="true"  stored="true"  default="NOW"  
multiValued="false"/>|


But, I would like a solution without modify the schema of Solr server.
I checked statistics page but I not found a useful date.

Any ideas.

Thanks