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