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