If a statement entry with identical text is found in the cache, then the stored set of compilation environment data for the statement is searched for a match between the stored compilation data and the compilation environment for {HEAD ~ the statement entry} of {TAIL ~ the new SQL request} 
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If a statement entry with identical text is found in the cache , then the stored set of compilation environment data for the statement is searched for a match between the stored compilation data and the compilation environment for { HEAD ~ the statement entry } of { TAIL ~ the new SQL request }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL