In {HEAD ~ some embodiments}, the sub strings associated with the indices are created based on a historical analysis of queries received from {TAIL ~ database users} 
In { HEAD ~ some embodiments } , the sub strings associated with the indices are created based on a historical analysis of queries received from { TAIL ~ database users }
OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL